4L60E Overrun Clutches in OD (3,2,1)?
TECH Enthusiast
Joined: Jan 2019
Posts: 677
Likes: 490
From: Roxana, IL
I am looking at my GM technician guide, pg. 51 that shows just the reverse diagram. It is in a PDF format. I have been trying to copy and paste the image, but it won't let me. I only have Adobe reader and not the full version. It will allow me to copy and paste the written portion of the page and I listed that below. Who knows vorteciroc may have been the guy that wrote it. LOL
You are correct that 12B feeds 12C,12D & 12E. Nether page 51 or 82 (the full diagram) really say much about circuit 12 @ the Manual valve. However you can determine that 12A,12B, 12C, 12D & 12E are passages transitioning PR oil from the VB to the case and back, which eventual becomes 12E. Here is the snag...
Follow me here
A) Line pressure feeds the manual valve and becomes PR oil & branches 3 ways.
1) goes back to the manual valve. from there it becomes 12A
2) goes to the low overrun valve, From there it turns into L/R oil and feeds the L/R side of the clutch
3) goes to the reverse input clutch.
remember PR oil is only supplied for garage shift feel and to dual feed the clutch itself. It will still get applied from the L/R side, even if it doesn't have PR oil. (don't leave out the Low overrun valve, then you won't have reverse. I did and did not have reverse on a 2003 KCD unit.)
"1 PRESSURE REGULATION
1a Manual Valve:
With the manual valve in the reverse position, line pressure
is directed into the reverse fluid circuit from the PR fluid
circuit already pressurized in Park.
1b Pressure Regulator and Reverse Boost Valves:
Reverse input fluid at the reverse boost valve boosts line
pressure for the additional torque requirements in Reverse.
Torque signal fluid pressure from the pressure control (PC)
solenoid acting on the reverse boost valve also helps
determine line pressure in Reverse depending on throttle
position and other PCM input signals. Reverse input fluid is
also routed through the reverse boost valve and seats the air
bleed ball check valve located in the fluid pump.
1c Transmission Fluid Pressure (TFP) Manual Valve
Position Switch:
Reverse input fluid is routed to the TFP manual valve position
switch. The TFP manual valve position switch signals the
PCM that the transmission is in Reverse.
2 LOW AND REVERSE CLUTCH APPLIES
2a #3 Ball Check Valve:
Reverse fluid seats the reverse input ball check valve (#3)
and is orificed into the reverse input fluid circuit. This
orifice (#17) controls the reverse input clutch apply when
engine speed is approximately at idle.
Note: Remember that the function of an orifice is to control the
flow rate of fluid and rate of apply or release of a clutch or band.
2b Reverse Abuse Valve:
When engine speed is above idle, reverse fluid acts on the
reverse abuse valve to move the valve against spring force.
This allows reverse fluid to feed the reverse input fluid
circuit quickly, bypassing the control of orifice #17.
2c Reverse Input Clutch:
Reverse input fluid is then routed to the reverse input clutch
piston to apply the reverse input clutch plates to obtain
reverse gear.
3 FLUID PRESSURE DIRECTED IN PREPARATION
FOR A SHIFT
3a 1-2 Shift Solenoid (SS) Valve:
The 1-2 SS valve remains energized (ON). 1-2 signal fluid
pressure is high with the 1-2 SS valve energized and keeps
the 1-2 shift valve in the downshifted position against spring
force. 1-2 signal fluid is also routed to the 3-4 shift valve.
3b 2-3 Shift Solenoid (SS) Valve:
The 2-3 SS valve remains energized (ON). 2-3 signal fluid
is high with the 2-3 SS valve energized and keeps the 2-3
shift valve and the 2-3 shuttle valve in the downshifted
position."
You are correct that 12B feeds 12C,12D & 12E. Nether page 51 or 82 (the full diagram) really say much about circuit 12 @ the Manual valve. However you can determine that 12A,12B, 12C, 12D & 12E are passages transitioning PR oil from the VB to the case and back, which eventual becomes 12E. Here is the snag...
Follow me here
A) Line pressure feeds the manual valve and becomes PR oil & branches 3 ways.
1) goes back to the manual valve. from there it becomes 12A
2) goes to the low overrun valve, From there it turns into L/R oil and feeds the L/R side of the clutch
3) goes to the reverse input clutch.
remember PR oil is only supplied for garage shift feel and to dual feed the clutch itself. It will still get applied from the L/R side, even if it doesn't have PR oil. (don't leave out the Low overrun valve, then you won't have reverse. I did and did not have reverse on a 2003 KCD unit.)
"1 PRESSURE REGULATION
1a Manual Valve:
With the manual valve in the reverse position, line pressure
is directed into the reverse fluid circuit from the PR fluid
circuit already pressurized in Park.
1b Pressure Regulator and Reverse Boost Valves:
Reverse input fluid at the reverse boost valve boosts line
pressure for the additional torque requirements in Reverse.
Torque signal fluid pressure from the pressure control (PC)
solenoid acting on the reverse boost valve also helps
determine line pressure in Reverse depending on throttle
position and other PCM input signals. Reverse input fluid is
also routed through the reverse boost valve and seats the air
bleed ball check valve located in the fluid pump.
1c Transmission Fluid Pressure (TFP) Manual Valve
Position Switch:
Reverse input fluid is routed to the TFP manual valve position
switch. The TFP manual valve position switch signals the
PCM that the transmission is in Reverse.
2 LOW AND REVERSE CLUTCH APPLIES
2a #3 Ball Check Valve:
Reverse fluid seats the reverse input ball check valve (#3)
and is orificed into the reverse input fluid circuit. This
orifice (#17) controls the reverse input clutch apply when
engine speed is approximately at idle.
Note: Remember that the function of an orifice is to control the
flow rate of fluid and rate of apply or release of a clutch or band.
2b Reverse Abuse Valve:
When engine speed is above idle, reverse fluid acts on the
reverse abuse valve to move the valve against spring force.
This allows reverse fluid to feed the reverse input fluid
circuit quickly, bypassing the control of orifice #17.
2c Reverse Input Clutch:
Reverse input fluid is then routed to the reverse input clutch
piston to apply the reverse input clutch plates to obtain
reverse gear.
3 FLUID PRESSURE DIRECTED IN PREPARATION
FOR A SHIFT
3a 1-2 Shift Solenoid (SS) Valve:
The 1-2 SS valve remains energized (ON). 1-2 signal fluid
pressure is high with the 1-2 SS valve energized and keeps
the 1-2 shift valve in the downshifted position against spring
force. 1-2 signal fluid is also routed to the 3-4 shift valve.
3b 2-3 Shift Solenoid (SS) Valve:
The 2-3 SS valve remains energized (ON). 2-3 signal fluid
is high with the 2-3 SS valve energized and keeps the 2-3
shift valve and the 2-3 shuttle valve in the downshifted
position."
TECH Enthusiast
Joined: Jan 2019
Posts: 677
Likes: 490
From: Roxana, IL
I have never been a automatic transmission "GURU", but I am a very good part's changer. 
LOL I can't hold a candle to the way engineer's like MaroonMonster or Vorteciroc think. I looked at Sonnax's product sheet. It explain's that they still use the HD 2-3 shift valve on the GM054-HD valve body.
As @vorteciroc explained...
"The Sonnax HD 2-3 Shift Valve keeps that Connection permanently Closed. And instead has a Hole Drilled (Cross-Leak Created) that allows D3 Fluid to enter the Overrun Circuit all the time (except in the D4/ OD Position)."
I've done some studying on this.
@MaroonMonsterLS1 gave a hint.... "study the 4-3 sequence valve"
So I'm going to throw this out here.
The 4-3 Sequence valve will exhaust overrun oil in 4th gear. Could it be as simple as introducing D4 oil from a passage next to the #5 or # 6 check ball.
My GM tech guide show's their function as
#5 OVERRUN CLUTCH FEED
Located in the valve body, it routes either overrun fluid or D2 fluid into the overrun clutch feed fluid circuit while blocking the other fluid circuit. Overrun clutch feed fluid feeds the overrun clutch fluid circuit in the Manual gear ranges to apply the overrun clutch.
#6 OVERRUN CLUTCH CONTROL
Located in the valve body, the #6 ball check valve helps control the overrun clutch apply rate. Overrun clutch feed fluid pressure seats the ball and is forced through orifice #20. This orifice slows the flow of overrun fluid to cushion the overrun clutch apply. When the overrun clutch releases, overrun clutch feed fluid unseats the ball for a quick exhaust.
Between the OE D2 feed, HD shift valve & this modification. That gives the overrun clutch D2, D3 & D4 oil.
If I'm wrong help me understand why...
LOL I can't hold a candle to the way engineer's like MaroonMonster or Vorteciroc think. I looked at Sonnax's product sheet. It explain's that they still use the HD 2-3 shift valve on the GM054-HD valve body.As @vorteciroc explained...
"The Sonnax HD 2-3 Shift Valve keeps that Connection permanently Closed. And instead has a Hole Drilled (Cross-Leak Created) that allows D3 Fluid to enter the Overrun Circuit all the time (except in the D4/ OD Position)."
I've done some studying on this.
@MaroonMonsterLS1 gave a hint.... "study the 4-3 sequence valve"
So I'm going to throw this out here.
The 4-3 Sequence valve will exhaust overrun oil in 4th gear. Could it be as simple as introducing D4 oil from a passage next to the #5 or # 6 check ball.
My GM tech guide show's their function as
#5 OVERRUN CLUTCH FEED
Located in the valve body, it routes either overrun fluid or D2 fluid into the overrun clutch feed fluid circuit while blocking the other fluid circuit. Overrun clutch feed fluid feeds the overrun clutch fluid circuit in the Manual gear ranges to apply the overrun clutch.
#6 OVERRUN CLUTCH CONTROL
Located in the valve body, the #6 ball check valve helps control the overrun clutch apply rate. Overrun clutch feed fluid pressure seats the ball and is forced through orifice #20. This orifice slows the flow of overrun fluid to cushion the overrun clutch apply. When the overrun clutch releases, overrun clutch feed fluid unseats the ball for a quick exhaust.
Between the OE D2 feed, HD shift valve & this modification. That gives the overrun clutch D2, D3 & D4 oil.
If I'm wrong help me understand why...
TECH Junkie
Joined: Jun 2008
Posts: 3,193
Likes: 1,376
From: Nitro Alley
I have not seen the Sonnax GM054-HD as of yet...
So I do not know for certain, how they set things up (I believe I Know what they are doing, but not certain).
I do this differently from Sonnax for sure.
The way in which I allow the Overrun Clutch to be on in all Gears except 4th-Gear (in all Gear Positions: D4, D3, D2, D1) does not use the Sonnax 2-3 HD Valve.
It is easier to just plug Separator-Plate Holes... Or in my case, make a Separator Plate.
#5 and #6 Check-***** are also removed.
That's enough for now, LOL!
So I do not know for certain, how they set things up (I believe I Know what they are doing, but not certain).
I do this differently from Sonnax for sure.
The way in which I allow the Overrun Clutch to be on in all Gears except 4th-Gear (in all Gear Positions: D4, D3, D2, D1) does not use the Sonnax 2-3 HD Valve.
It is easier to just plug Separator-Plate Holes... Or in my case, make a Separator Plate.
#5 and #6 Check-***** are also removed.
That's enough for now, LOL!
TECH Regular
Joined: Jan 2013
Posts: 463
Likes: 179
I am looking at my GM technician guide, pg. 51 that shows just the reverse diagram. It is in a PDF format. I have been trying to copy and paste the image, but it won't let me. I only have Adobe reader and not the full version. It will allow me to copy and paste the written portion of the page and I listed that below. Who knows vorteciroc may have been the guy that wrote it. LOL
You are correct that 12B feeds 12C,12D & 12E. Nether page 51 or 82 (the full diagram) really say much about circuit 12 @ the Manual valve. However you can determine that 12A,12B, 12C, 12D & 12E are passages transitioning PR oil from the VB to the case and back, which eventual becomes 12E. Here is the snag...
Follow me here
A) Line pressure feeds the manual valve and becomes PR oil & branches 3 ways.
1) goes back to the manual valve. from there it becomes 12A
2) goes to the low overrun valve, From there it turns into L/R oil and feeds the L/R side of the clutch
3) goes to the reverse input clutch.
remember PR oil is only supplied for garage shift feel and to dual feed the clutch itself. It will still get applied from the L/R side, even if it doesn't have PR oil. (don't leave out the Low overrun valve, then you won't have reverse. I did and did not have reverse on a 2003 KCD unit.)
"1 PRESSURE REGULATION
1a Manual Valve:
With the manual valve in the reverse position, line pressure
is directed into the reverse fluid circuit from the PR fluid
circuit already pressurized in Park.
1b Pressure Regulator and Reverse Boost Valves:
Reverse input fluid at the reverse boost valve boosts line
pressure for the additional torque requirements in Reverse.
Torque signal fluid pressure from the pressure control (PC)
solenoid acting on the reverse boost valve also helps
determine line pressure in Reverse depending on throttle
position and other PCM input signals. Reverse input fluid is
also routed through the reverse boost valve and seats the air
bleed ball check valve located in the fluid pump.
1c Transmission Fluid Pressure (TFP) Manual Valve
Position Switch:
Reverse input fluid is routed to the TFP manual valve position
switch. The TFP manual valve position switch signals the
PCM that the transmission is in Reverse.
2 LOW AND REVERSE CLUTCH APPLIES
2a #3 Ball Check Valve:
Reverse fluid seats the reverse input ball check valve (#3)
and is orificed into the reverse input fluid circuit. This
orifice (#17) controls the reverse input clutch apply when
engine speed is approximately at idle.
Note: Remember that the function of an orifice is to control the
flow rate of fluid and rate of apply or release of a clutch or band.
2b Reverse Abuse Valve:
When engine speed is above idle, reverse fluid acts on the
reverse abuse valve to move the valve against spring force.
This allows reverse fluid to feed the reverse input fluid
circuit quickly, bypassing the control of orifice #17.
2c Reverse Input Clutch:
Reverse input fluid is then routed to the reverse input clutch
piston to apply the reverse input clutch plates to obtain
reverse gear.
3 FLUID PRESSURE DIRECTED IN PREPARATION
FOR A SHIFT
3a 1-2 Shift Solenoid (SS) Valve:
The 1-2 SS valve remains energized (ON). 1-2 signal fluid
pressure is high with the 1-2 SS valve energized and keeps
the 1-2 shift valve in the downshifted position against spring
force. 1-2 signal fluid is also routed to the 3-4 shift valve.
3b 2-3 Shift Solenoid (SS) Valve:
The 2-3 SS valve remains energized (ON). 2-3 signal fluid
is high with the 2-3 SS valve energized and keeps the 2-3
shift valve and the 2-3 shuttle valve in the downshifted
position."
You are correct that 12B feeds 12C,12D & 12E. Nether page 51 or 82 (the full diagram) really say much about circuit 12 @ the Manual valve. However you can determine that 12A,12B, 12C, 12D & 12E are passages transitioning PR oil from the VB to the case and back, which eventual becomes 12E. Here is the snag...
Follow me here
A) Line pressure feeds the manual valve and becomes PR oil & branches 3 ways.
1) goes back to the manual valve. from there it becomes 12A
2) goes to the low overrun valve, From there it turns into L/R oil and feeds the L/R side of the clutch
3) goes to the reverse input clutch.
remember PR oil is only supplied for garage shift feel and to dual feed the clutch itself. It will still get applied from the L/R side, even if it doesn't have PR oil. (don't leave out the Low overrun valve, then you won't have reverse. I did and did not have reverse on a 2003 KCD unit.)
"1 PRESSURE REGULATION
1a Manual Valve:
With the manual valve in the reverse position, line pressure
is directed into the reverse fluid circuit from the PR fluid
circuit already pressurized in Park.
1b Pressure Regulator and Reverse Boost Valves:
Reverse input fluid at the reverse boost valve boosts line
pressure for the additional torque requirements in Reverse.
Torque signal fluid pressure from the pressure control (PC)
solenoid acting on the reverse boost valve also helps
determine line pressure in Reverse depending on throttle
position and other PCM input signals. Reverse input fluid is
also routed through the reverse boost valve and seats the air
bleed ball check valve located in the fluid pump.
1c Transmission Fluid Pressure (TFP) Manual Valve
Position Switch:
Reverse input fluid is routed to the TFP manual valve position
switch. The TFP manual valve position switch signals the
PCM that the transmission is in Reverse.
2 LOW AND REVERSE CLUTCH APPLIES
2a #3 Ball Check Valve:
Reverse fluid seats the reverse input ball check valve (#3)
and is orificed into the reverse input fluid circuit. This
orifice (#17) controls the reverse input clutch apply when
engine speed is approximately at idle.
Note: Remember that the function of an orifice is to control the
flow rate of fluid and rate of apply or release of a clutch or band.
2b Reverse Abuse Valve:
When engine speed is above idle, reverse fluid acts on the
reverse abuse valve to move the valve against spring force.
This allows reverse fluid to feed the reverse input fluid
circuit quickly, bypassing the control of orifice #17.
2c Reverse Input Clutch:
Reverse input fluid is then routed to the reverse input clutch
piston to apply the reverse input clutch plates to obtain
reverse gear.
3 FLUID PRESSURE DIRECTED IN PREPARATION
FOR A SHIFT
3a 1-2 Shift Solenoid (SS) Valve:
The 1-2 SS valve remains energized (ON). 1-2 signal fluid
pressure is high with the 1-2 SS valve energized and keeps
the 1-2 shift valve in the downshifted position against spring
force. 1-2 signal fluid is also routed to the 3-4 shift valve.
3b 2-3 Shift Solenoid (SS) Valve:
The 2-3 SS valve remains energized (ON). 2-3 signal fluid
is high with the 2-3 SS valve energized and keeps the 2-3
shift valve and the 2-3 shuttle valve in the downshifted
position."
Also missing from the plate is 35c and 35a. This essentially deletes the connection between checkball #5 & #6 and also blocks off the orificed D2 to checkball #5. There is also a NEW hole above 34e. I THINK this new hole is D3 oil from the 2-3 shift valve and fills cavity 35 which would feed 35e, the the 3/4 sequencer and then apply the overrun clutch? I do not have a valve body infront of me so tracing this via the manual is difficult, but I think this allows the overrun clutch to be applied in any gear with the shifter lever in D....
Last edited by tayto; Aug 3, 2022 at 09:21 PM.
TECH Regular
Joined: Jan 2013
Posts: 463
Likes: 179
This stuff is really not difficult if you take the time to look at it.
I do not want people to be afraid of it...
Give it a try, if you don't quite get it (understand it), who cares? ...it can't do you any harm!
Maroon Monster (who is excellent at all of this now) picked up all this stuff in very little time, with no formal Training/ Education.
He has a BS or MS in Engineering or Science, and taught Himself in a few Years!!!
Many of these Hydraulic Modifications were first realized by looking at a Transmission that was Malfunctioning from a Cross-Leak.
Kind of Happy Accidental Discoveries.
If you look at what the Sonnax HD 2-3 Shift Valve actually is...
It just removes one function of the Valve, leaving the rest intact/ identical to the OEM Valve.
It blocks off a Connection between 2 Passages; the D3 Circuit into the Valve Bore...
and the Overrun Circuit out of the Valve Bore.
The OEM Valve Opens this Connection if the Gear-Selector (Manual Valve) is in the D3/ M3 Position, operating in 3RD-Gear ONLY (NO 1st or 2nd).
Which is the complaint with the Original Design/ Function of this Transmission.
The Sonnax HD 2-3 Shift Valve keeps that Connection permanently Closed.
And instead has a Hole Drilled (Cross-Leak Created) that allows D3 Fluid to enter the Overrun Circuit all the time (except in the D4/ OD Position).
The Sonnax GM054-HD Valve-Body changes things so that the Overrun Clutch is always ON except when the Transmission is operating in 4th-Gear
(Regardless of the Gear-Selector Position: D4, D3, D2, or D1).
Here is another Hint:
If you look at the Separator Plate, it will show you that D4 Fluid and Overrun Fluid are right next to each other in different places.
There is more to it, such as releasing the Overrun Clutch...
But that should get you started.
I do not want people (or Memebers) thinking that this is all Voo-Doo Pseudo-Science.
I do not want people to be afraid of it...
Give it a try, if you don't quite get it (understand it), who cares? ...it can't do you any harm!
Maroon Monster (who is excellent at all of this now) picked up all this stuff in very little time, with no formal Training/ Education.
He has a BS or MS in Engineering or Science, and taught Himself in a few Years!!!
Many of these Hydraulic Modifications were first realized by looking at a Transmission that was Malfunctioning from a Cross-Leak.
Kind of Happy Accidental Discoveries.
If you look at what the Sonnax HD 2-3 Shift Valve actually is...
It just removes one function of the Valve, leaving the rest intact/ identical to the OEM Valve.
It blocks off a Connection between 2 Passages; the D3 Circuit into the Valve Bore...
and the Overrun Circuit out of the Valve Bore.
The OEM Valve Opens this Connection if the Gear-Selector (Manual Valve) is in the D3/ M3 Position, operating in 3RD-Gear ONLY (NO 1st or 2nd).
Which is the complaint with the Original Design/ Function of this Transmission.
The Sonnax HD 2-3 Shift Valve keeps that Connection permanently Closed.
And instead has a Hole Drilled (Cross-Leak Created) that allows D3 Fluid to enter the Overrun Circuit all the time (except in the D4/ OD Position).
The Sonnax GM054-HD Valve-Body changes things so that the Overrun Clutch is always ON except when the Transmission is operating in 4th-Gear
(Regardless of the Gear-Selector Position: D4, D3, D2, or D1).
Here is another Hint:
If you look at the Separator Plate, it will show you that D4 Fluid and Overrun Fluid are right next to each other in different places.
There is more to it, such as releasing the Overrun Clutch...
But that should get you started.
I do not want people (or Memebers) thinking that this is all Voo-Doo Pseudo-Science.
TECH Enthusiast
Joined: Jan 2019
Posts: 677
Likes: 490
From: Roxana, IL
Won't the 4-3 sequence valve dump the Overrun oil in 4th???
Last edited by Tranzman; Aug 4, 2022 at 10:16 PM. Reason: added ??
TECH Junkie
Joined: Jun 2008
Posts: 3,193
Likes: 1,376
From: Nitro Alley
It's Funny how Both the THM700-R4 and 4L60E share the same type of
.............Redacted............. Circuits ..............Redacted.............
that can be used to help other Circuits via Cross-Leaks.
.............Redacted............. Circuits ..............Redacted.............
that can be used to help other Circuits via Cross-Leaks.
Last edited by vorteciroc; Aug 5, 2022 at 06:11 PM.
TECH Regular
Joined: Jan 2013
Posts: 463
Likes: 179
thank you to maroon & vortec for leaving a bread crumb trail. could you also drill between the 2 cavities in the valve body? i guess if it's done by separator plate then a valve body can easily be put back to "stock".
also, was I on the right path with the corvette separator plate?
also, was I on the right path with the corvette separator plate?
On The Tree
Joined: Apr 2021
Posts: 187
Likes: 23
From: Israel
After carefully reading this thread, I am sure that football player if we've all been sitting in one class...
Too bad i cant grab Tranzman and punch him in the face screaming : WHAT I HAVE TO DO TO MAKE THE OVERRUNS WORK?!
Im too dumb to figure out these hydroalics by myself. This is sure a lot of information and years of learning.
I think the proper thing to do here is to credit Maroon and Vortec for all what they learned and share here.
You guys make the LS1Tech Tranny forums the best one of all of them out there.
I will apply this mod, even tho my TB is a stock one. Too bad i didnt know this earlier.
Thanks for your info.
Too bad i cant grab Tranzman and punch him in the face screaming : WHAT I HAVE TO DO TO MAKE THE OVERRUNS WORK?!
Im too dumb to figure out these hydroalics by myself. This is sure a lot of information and years of learning.
I think the proper thing to do here is to credit Maroon and Vortec for all what they learned and share here.
You guys make the LS1Tech Tranny forums the best one of all of them out there.
I will apply this mod, even tho my TB is a stock one. Too bad i didnt know this earlier.
Thanks for your info.
TECH Regular
Joined: Jan 2013
Posts: 463
Likes: 179
After carefully reading this thread, I am sure that football player if we've all been sitting in one class...
Too bad i cant grab Tranzman and punch him in the face screaming : WHAT I HAVE TO DO TO MAKE THE OVERRUNS WORK?!
Im too dumb to figure out these hydroalics by myself. This is sure a lot of information and years of learning.
I think the proper thing to do here is to credit Maroon and Vortec for all what they learned and share here.
You guys make the LS1Tech Tranny forums the best one of all of them out there.
I will apply this mod, even tho my TB is a stock one. Too bad i didnt know this earlier.
Thanks for your info.
Too bad i cant grab Tranzman and punch him in the face screaming : WHAT I HAVE TO DO TO MAKE THE OVERRUNS WORK?!
Im too dumb to figure out these hydroalics by myself. This is sure a lot of information and years of learning.
I think the proper thing to do here is to credit Maroon and Vortec for all what they learned and share here.
You guys make the LS1Tech Tranny forums the best one of all of them out there.
I will apply this mod, even tho my TB is a stock one. Too bad i didnt know this earlier.
Thanks for your info.
TECH Enthusiast
Joined: Jan 2019
Posts: 677
Likes: 490
From: Roxana, IL
After carefully reading this thread, I am sure that football player if we've all been sitting in one class...
Too bad i cant grab Tranzman and punch him in the face screaming : WHAT I HAVE TO DO TO MAKE THE OVERRUNS WORK?!
Im too dumb to figure out these hydroalics by myself. This is sure a lot of information and years of learning.
I think the proper thing to do here is to credit Maroon and Vortec for all what they learned and share here.
You guys make the LS1Tech Tranny forums the best one of all of them out there.
I will apply this mod, even tho my TB is a stock one. Too bad i didnt know this earlier.
Thanks for your info.
Too bad i cant grab Tranzman and punch him in the face screaming : WHAT I HAVE TO DO TO MAKE THE OVERRUNS WORK?!
Im too dumb to figure out these hydroalics by myself. This is sure a lot of information and years of learning.
I think the proper thing to do here is to credit Maroon and Vortec for all what they learned and share here.
You guys make the LS1Tech Tranny forums the best one of all of them out there.
I will apply this mod, even tho my TB is a stock one. Too bad i didnt know this earlier.
Thanks for your info.
This post is not about just making the overrun clutch work. Because it works as the manufacturer wanted it too without any modification.
This post identified a NEW AVAILABLE part that gave a full time feed of the overrun clutch for $500.00 plus. They were also comparing the current Sonnax overrun modification allowing it to come on in M1, M2 & M3.
Maroonmonsterls1 & vorteciroc threw out a CHALLANGE to all of us to figure out on our OWN. Maroonmonsterls1 said that he has had that information since 2017. Both Maroonmonsterls1 & vorteciroc gave some hints to figure it. Then once figured out, share it themselves.
The information that I shared so far had nothing to do with the OD overrun modification that the original poster asked about. Someone shared that a corvette plate eliminated a PR feed and said the because of that reverse would not apply. What I shared supported that even though that port was eliminated, that reverse would still apply. That person since shared that they were mistaken in the hole # that was eliminated.
So far if you want to do any sort of overrun modification you have 2 options as others have already pointed out.
1) buy the Sonnax HD 2-3 shift valve. part # 77754-41
2) buy either the GM053-HD or the GM054-HD valve body.
On The Tree
Joined: Apr 2021
Posts: 187
Likes: 23
From: Israel
Punching me in the face screaming that, won't get you anywhere. Because I don't know how to do it either. After several days and several hours of studying circuits, I do have a theory, but right now it's just a theory.
This post is not about just making the overrun clutch work. Because it works as the manufacturer wanted it too without any modification.
This post identified a NEW AVAILABLE part that gave a full time feed of the overrun clutch for $500.00 plus. They were also comparing the current Sonnax overrun modification allowing it to come on in M1, M2 & M3.
Maroonmonsterls1 & vorteciroc threw out a CHALLANGE to all of us to figure out on our OWN. Maroonmonsterls1 said that he has had that information since 2017. Both Maroonmonsterls1 & vorteciroc gave some hints to figure it. Then once figured out, share it themselves.
The information that I shared so far had nothing to do with the OD overrun modification that the original poster asked about. Someone shared that a corvette plate eliminated a PR feed and said the because of that reverse would not apply. What I shared supported that even though that port was eliminated, that reverse would still apply. That person since shared that they were mistaken in the hole # that was eliminated.
So far if you want to do any sort of overrun modification you have 2 options as others have already pointed out.
1) buy the Sonnax HD 2-3 shift valve. part # 77754-41
2) buy either the GM053-HD or the GM054-HD valve body.
This post is not about just making the overrun clutch work. Because it works as the manufacturer wanted it too without any modification.
This post identified a NEW AVAILABLE part that gave a full time feed of the overrun clutch for $500.00 plus. They were also comparing the current Sonnax overrun modification allowing it to come on in M1, M2 & M3.
Maroonmonsterls1 & vorteciroc threw out a CHALLANGE to all of us to figure out on our OWN. Maroonmonsterls1 said that he has had that information since 2017. Both Maroonmonsterls1 & vorteciroc gave some hints to figure it. Then once figured out, share it themselves.
The information that I shared so far had nothing to do with the OD overrun modification that the original poster asked about. Someone shared that a corvette plate eliminated a PR feed and said the because of that reverse would not apply. What I shared supported that even though that port was eliminated, that reverse would still apply. That person since shared that they were mistaken in the hole # that was eliminated.
So far if you want to do any sort of overrun modification you have 2 options as others have already pointed out.
1) buy the Sonnax HD 2-3 shift valve. part # 77754-41
2) buy either the GM053-HD or the GM054-HD valve body.
The 3-4 sequence valve train can feed overrun and there seems like a place to block 4th but im not sure.
Tomorrow, i'll take a valve body and a sep plate. Print page 66A and 58A and compare them.
I think Vortec and Maroon gave not what so called hints, it's almost a complete solution and all what we have to find is where to drill and what to plug. If we throw away CB#5, that means our drill size is going to matter too. only 2 actions with removing 5/6 CB's.. I will feel guilty if i dont figure this out, because even Sonnax did.
I'll post what i've found tomorrow and lets see what our gurus says about what i've found.
TECH Enthusiast
Joined: Jan 2019
Posts: 677
Likes: 490
From: Roxana, IL
So here is my theory for @MaroonMonsterLS1 & @vorteciroc to critique. I do see a possible issue i shared later.
Full time overrun clutch (except 4th)
1. Drill/feed circuit 35c with D4 oil from 17F at #5 check ball. (This feeds the overrun clutch from 36/36a to 37a at the 4-3 sequence instead of 35B or 39.)
2. Block separator plate holes 35B & 39. (by blocking 35B & 39 you will not be back feeding the D2 & overrun circuit)
3. Remove check ball #5
4. Remove check ball #6 (optional, overrun clutch feed has an OE orificed apply, leaving the check-ball in makes use of the orifice)
New oil circuit layout all modes
OD mode
· 1st, 2nd, 3rd 35c to 35e/36 to 36a to (4-3 sequence) 37a to overrun clutch.
· 4th 1-2 signal oil moves the 3-4 shift valve. 3-4 signal oil becomes 4th signal oil and moves the 3-4 relay/4-3 sequence valve and D4 oil feeding the overrun clutch gets exhausted. The only issue I see is in 4th you are exhausting D4 oil which starts out as line. Will this be enough of a leak to lower overall line pressure in 4th gear?
· 4-3 downshift, the 1-2 shift solenoid is turned off eliminating 1-2 signal oil allowing the 3-4 shift valve to move to the 3rd gear position. This allows the 3-4 relay/4-3 sequence to supply overrun oil to the overrun clutch.
· 3-2 downshift like the OD 1st, 2nd or 3rd.
M3
· OE supplies D3 oil to the 2-3 shift valve which dead ends at the blocked 35b. The new drilled hole feeds 35c that supplies 35d,35e & 36. 36 supplies 36a (overrun clutch feed) which turns into overrun oil at the 4-3 sequence valve. D3 oil can still supply the PSM it’s signal. D3 oil still dead ends at the spring side of the 3-4 shift valve.
M2
· OE feeds overruns via the 4-3 sequence valve. The new feed is the same except it is fed from D4 oil being introduced the 35c instead. D3, D2 oil is still able to feed the PSM signal. D3 oil still dead ends at the spring side of the 3-4 shift valve & the 2-3 shift valve. D2 oil dead ends at the blocked 39 plate hole & 2-3 shuttle valve & 2-3 shift valve.
M1
· There is no real change here from the M2 feed. M1 just adds Low oil to the low reverse circuit for clutch apply.
Full time overrun clutch (except 4th)
1. Drill/feed circuit 35c with D4 oil from 17F at #5 check ball. (This feeds the overrun clutch from 36/36a to 37a at the 4-3 sequence instead of 35B or 39.)
2. Block separator plate holes 35B & 39. (by blocking 35B & 39 you will not be back feeding the D2 & overrun circuit)
3. Remove check ball #5
4. Remove check ball #6 (optional, overrun clutch feed has an OE orificed apply, leaving the check-ball in makes use of the orifice)
New oil circuit layout all modes
OD mode
· 1st, 2nd, 3rd 35c to 35e/36 to 36a to (4-3 sequence) 37a to overrun clutch.
· 4th 1-2 signal oil moves the 3-4 shift valve. 3-4 signal oil becomes 4th signal oil and moves the 3-4 relay/4-3 sequence valve and D4 oil feeding the overrun clutch gets exhausted. The only issue I see is in 4th you are exhausting D4 oil which starts out as line. Will this be enough of a leak to lower overall line pressure in 4th gear?
· 4-3 downshift, the 1-2 shift solenoid is turned off eliminating 1-2 signal oil allowing the 3-4 shift valve to move to the 3rd gear position. This allows the 3-4 relay/4-3 sequence to supply overrun oil to the overrun clutch.
· 3-2 downshift like the OD 1st, 2nd or 3rd.
M3
· OE supplies D3 oil to the 2-3 shift valve which dead ends at the blocked 35b. The new drilled hole feeds 35c that supplies 35d,35e & 36. 36 supplies 36a (overrun clutch feed) which turns into overrun oil at the 4-3 sequence valve. D3 oil can still supply the PSM it’s signal. D3 oil still dead ends at the spring side of the 3-4 shift valve.
M2
· OE feeds overruns via the 4-3 sequence valve. The new feed is the same except it is fed from D4 oil being introduced the 35c instead. D3, D2 oil is still able to feed the PSM signal. D3 oil still dead ends at the spring side of the 3-4 shift valve & the 2-3 shift valve. D2 oil dead ends at the blocked 39 plate hole & 2-3 shuttle valve & 2-3 shift valve.
M1
· There is no real change here from the M2 feed. M1 just adds Low oil to the low reverse circuit for clutch apply.
Last edited by Tranzman; Aug 8, 2022 at 06:56 PM. Reason: grammer
TECH Junkie
Joined: Jun 2008
Posts: 3,193
Likes: 1,376
From: Nitro Alley
Guys, there are several ways to accomplish the same goal...
If you guys want to do this without drilling into any Aluminum, that is up to you.
I have NOT seen the Sonnax Valve-Body... did they drill through the Accumulator Valve Bore?
I don't know!
But you guys can make this work, regardless of the way I do it, or MaroonMonster does it, or even Sonnax does it.
That is whats FUN!
Do it your own way... if it still accomplishes the same end result, then GREAT!
If you guys want to do this without drilling into any Aluminum, that is up to you.
I have NOT seen the Sonnax Valve-Body... did they drill through the Accumulator Valve Bore?
I don't know!
But you guys can make this work, regardless of the way I do it, or MaroonMonster does it, or even Sonnax does it.
That is whats FUN!
Do it your own way... if it still accomplishes the same end result, then GREAT!