Sonnax HD 2-3 Shift valve install question
Thread Starter
Staging Lane
Joined: May 2012
Posts: 54
Likes: 0
Sonnax HD 2-3 Shift valve install question Can any of the pros explain how they modify the valve body?
After reading instructions,, it says to use an 1/ 8th inch drill bit, but not clear if you drill a hole through one of the vb walls at an angle, or notch the top of the wall.
Mentions cutting plate gasket as an alternate option, but this seems like it would not allow proper fluid flow?
What is best method on a. 4L60e?
After reading instructions,, it says to use an 1/ 8th inch drill bit, but not clear if you drill a hole through one of the vb walls at an angle, or notch the top of the wall.
Mentions cutting plate gasket as an alternate option, but this seems like it would not allow proper fluid flow?
What is best method on a. 4L60e?
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
I'm certainly not a pro, but this is what I did. Since I didn't want drill shavings in the valve body, I used wire cutters to notch a "V" into the wall. I compared the size to a 1/8" drill to make sure it was big enough. I've done this to several transmission that I tested and it worked. You can tell that the 2-3 shift valve is installed because with the shifter in [D3], the 3-2 downshift is quite abrupt since the overrun clutch stays engaged.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
It makes no difference in [D4] and therefore does not affect normal driving in any way.
As I understand it, when in [D3] it keeps the overrun clutch engaged in all gears to reduce strain on the forward sprag. So yes, in [D3] you feel a slightly annoying jerk when the car downshifts from 3rd to 2rd, but since I only drive in [D3] at the track, that is a non-issue.
As I understand it, when in [D3] it keeps the overrun clutch engaged in all gears to reduce strain on the forward sprag. So yes, in [D3] you feel a slightly annoying jerk when the car downshifts from 3rd to 2rd, but since I only drive in [D3] at the track, that is a non-issue.
TECH Resident
Joined: May 2006
Posts: 969
Likes: 119
It keeps the overrun clutches on all the time when in "1", "2", or "D" just the same as the 700R4. This will help the 3-4 clutch pack live longer when in the "D" shifter position, when compared to a stock 4L60E setup. Makes no difference in "OD" shifter position. The downshifts are more pronounced. You could add the 4 slots in the steel cover that holds the cushion spring to the Corvette servo. TransGo does this modification in their regular shift kit. I always do this when adding the Sonnax HD 2-3 shift valve to a 4L60E, just the same as with all 700R4's
Thread Starter
Staging Lane
Joined: May 2012
Posts: 54
Likes: 0
I bought this valve today. The trans shop showed me how they drilled the vb wall at an angle to connect the passages.
Dana,
Could you explin how to modify the servo steel? I assume this is the flat steel cover that houses the cushion springs.
Is it really necessary?
The reason I am installing the valve is because my 2.59 rear gear makes 4=2 freeway downshifts the norm. I read some older posts that stated this will roll the sprag. I have not had this problem in over 50 k miles, but figured I would install the valve, manually downshift to 3rd and let the computer decide on going to 2nd or not.
My 3-2 down shift has always had a slightly sloppy small flare at lighter throttle. 3-2 is solid at WOT and 4-2 WOT is solid.
Dana,
Could you explin how to modify the servo steel? I assume this is the flat steel cover that houses the cushion springs.
Is it really necessary?
The reason I am installing the valve is because my 2.59 rear gear makes 4=2 freeway downshifts the norm. I read some older posts that stated this will roll the sprag. I have not had this problem in over 50 k miles, but figured I would install the valve, manually downshift to 3rd and let the computer decide on going to 2nd or not.
My 3-2 down shift has always had a slightly sloppy small flare at lighter throttle. 3-2 is solid at WOT and 4-2 WOT is solid.
On The Tree
Joined: Jun 2015
Posts: 113
Likes: 12
From: Hopewell Junction NY
I'm certainly not a pro, but this is what I did. Since I didn't want drill shavings in the valve body, I used wire cutters to notch a "V" into the wall. I compared the size to a 1/8" drill to make sure it was big enough. I've done this to several transmission that I tested and it worked. You can tell that the 2-3 shift valve is installed because with the shifter in [D3], the 3-2 downshift is quite abrupt since the overrun clutch stays engaged.
I know its an old thread. Just wanted to ask a question? I installed the 2-3 valve but opted to cut the vb gasket between passages instead of drilling, for the same reason, didnt want filings in the passages. Sonnax gives you the option to do either in the directions. So Im not getting that abrupt 3-2 downshift in D3 feeling as you describe. When I downshift it manually from D3 to D2 I feel it! But in D3 when it downshifts it feels just like it would if the car were in OD. I hope I dont have to drop this VB to do this again! Is this similar to any others experiences? Thanks
Trending Topics
You wont notice a very abrupt downshift if this is your only mod. With the Transgo HD-2 Kit it is noticeable. You wont get as much flow modifying the gasket compared to drilling the whole, but it wont make much of a difference. As long as you cut the gasket as described in the installation instructions you should be fine. The Sonnax HD 2-3 Shift Valve is definitely a great mod for the 4L60E trans.
To clarify what PBA stated. This has no change on transmission operation when the gear selector is in the "D" position. It only applies the overrun clutches in "1" "2" and "3" gear selection. It also has absolutely no affect on the 3-4 Clutch pack since those clutches only engage in OD, or when the "D" is selected on the gear selector. If you did want to prolong the 3-4 clutches, the Sonnax Billet 4th Gear Super Hold Dual Servo is a easy mod to install and one of the best 3-4 Clutch mods to do. It allows for faster 3-4 clutch engagement (Less slipping) and 40% more holding pressure. I would also do the Vette servo since you are already in there installing the other servo.
To clarify what PBA stated. This has no change on transmission operation when the gear selector is in the "D" position. It only applies the overrun clutches in "1" "2" and "3" gear selection. It also has absolutely no affect on the 3-4 Clutch pack since those clutches only engage in OD, or when the "D" is selected on the gear selector. If you did want to prolong the 3-4 clutches, the Sonnax Billet 4th Gear Super Hold Dual Servo is a easy mod to install and one of the best 3-4 Clutch mods to do. It allows for faster 3-4 clutch engagement (Less slipping) and 40% more holding pressure. I would also do the Vette servo since you are already in there installing the other servo.
Last edited by 07NBSChevy; Apr 25, 2017 at 04:52 AM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo On The Tree
Joined: Jun 2015
Posts: 113
Likes: 12
From: Hopewell Junction NY
You wont notice a very abrupt downshift if this is your only mod. With the Transgo HD-2 Kit it is noticeable. You wont get as much flow modifying the gasket compared to drilling the whole, but it wont make much of a difference. As long as you cut the gasket as described in the installation instructions you should be fine. The Sonnax HD 2-3 Shift
Valve is definitely a great mod for the 4L60E trans.
To clarify what PBA stated. This has no change on transmission operation when the gear selector is in the "D" position. It only applies the overrun clutches in "1" "2" and "3" gear selection. It also has absolutely no affect on the 3-4 Clutch pack since those clutches only engage in OD, or when the "D" is selected on the gear selector. If you did want to prolong the 3-4 clutches, the Sonnax Billet 4th Gear Super Hold Dual Servo is a easy mod to install and one of the best 3-4 Clutch mods to do. It allows for faster 3-4 clutch engagement (Less slipping) and 40% more holding pressure. I would also do the Vette servo since you are already in there installing the other servo.
Valve is definitely a great mod for the 4L60E trans.
To clarify what PBA stated. This has no change on transmission operation when the gear selector is in the "D" position. It only applies the overrun clutches in "1" "2" and "3" gear selection. It also has absolutely no affect on the 3-4 Clutch pack since those clutches only engage in OD, or when the "D" is selected on the gear selector. If you did want to prolong the 3-4 clutches, the Sonnax Billet 4th Gear Super Hold Dual Servo is a easy mod to install and one of the best 3-4 Clutch mods to do. It allows for faster 3-4 clutch engagement (Less slipping) and 40% more holding pressure. I would also do the Vette servo since you are already in there installing the other servo.
Teching In
Joined: Apr 2017
Posts: 47
Likes: 1
From: Oregon
It keeps the overrun clutches on all the time when in "1", "2", or "D" just the same as the 700R4. This will help the 3-4 clutch pack live longer when in the "D" shifter position, when compared to a stock 4L60E setup. Makes no difference in "OD" shifter position. The downshifts are more pronounced. You could add the 4 slots in the steel cover that holds the cushion spring to the Corvette servo. TransGo does this modification in their regular shift kit. I always do this when adding the Sonnax HD 2-3 shift valve to a 4L60E, just the same as with all 700R4's
For a heavy, low horsepower van used for towing about 4500 lbs, would the sonnax shift valve and the slotted cover modification be helpful (in addition to the more common upgrades discussed on the forum) or is this recommended more for high horsepower use instead of HD?
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
The Sonnax HD 2-3 shift valve does actually help the 3/4 clutch live longer as long as you race in [D3].
If your race in [D3] without the shift valve, then during the 2->3 shift the overrun clutches are applied and this diverts some fluid/pressure away from the 3/4 clutch which is also being applied.
With the valve you should race in [D3]. Since the overrun clutches are applied in all gears, there is no diversion of fluid away from the 3/4 clutch during the 2->3 shift.
Having the overrun clutches applied helps reduce the load on the forward sprag.
So this shift valve helps in two ways.
If your race in [D3] without the shift valve, then during the 2->3 shift the overrun clutches are applied and this diverts some fluid/pressure away from the 3/4 clutch which is also being applied.
With the valve you should race in [D3]. Since the overrun clutches are applied in all gears, there is no diversion of fluid away from the 3/4 clutch during the 2->3 shift.
Having the overrun clutches applied helps reduce the load on the forward sprag.
So this shift valve helps in two ways.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
...
If you did want to prolong the 3-4 clutches, the Sonnax Billet 4th Gear Super Hold Dual Servo is a easy mod to install and one of the best 3-4 Clutch mods to do. It allows for faster 3-4 clutch engagement (Less slipping) and 40% more holding pressure. I would also do the Vette servo since you are already in there installing the other servo.
If you did want to prolong the 3-4 clutches, the Sonnax Billet 4th Gear Super Hold Dual Servo is a easy mod to install and one of the best 3-4 Clutch mods to do. It allows for faster 3-4 clutch engagement (Less slipping) and 40% more holding pressure. I would also do the Vette servo since you are already in there installing the other servo.
The Sonnax Billet 4th Gear Servo (or equivalent) helps with the 3->4 shift to reduce slippage of the band. It is also recommended for towing vehicles to reduce band slippage under heavy towing at highway speeds.
It has absolutely no effect on the 3/4 clutch.
Here is Sonnax's doco on it:
http://www.sonnax.com/parts/2473-4th...dual-servo-kit
By stating "poor 3-4 shift quality" they are referring to the 3-> 4 shift, nothing about the 2->3 shift and no mention of the 3/4 clutch.
Still the Sonnax 2nd and 4th billet servos are excellent upgrades included in most of the sponsors built transmissions.
TECH Resident
Joined: May 2006
Posts: 969
Likes: 119
The Sonnax 2nd apply servo will help the 3-4 clutch pack live longer as it is the 3rd gear accumulator, which puts more oil to the 3-4 clutches on the 2-3 shift at all throttle openings. The Sonnax 4th apply servo will have more holding power (40%) than the stock 4th apply servo. This servo is a must if you plan on making 3-4 WOT shifts more than once in awhile. This 4th apply servo does nothing for the 3-4 clutch pack. It only affects the 3-4 shift. Making the modifications to the steel spring retainer as TransGo does in their regular Shift kit, will help on the downshift clunks when slowing down normally with the shifter in the "D" position (3rd gear).
Last edited by PBA; May 1, 2017 at 06:07 PM.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Thanks for the addition info that the Sonnax 2nd Gear Servo will help the 3/4 clutch live longer. And confirming that the 4th Gear Servo has no effect on the 3/4 clutch.
Always appreciate your input and advice!
Always appreciate your input and advice!
Teching In
Joined: Apr 2017
Posts: 47
Likes: 1
From: Oregon
What I meant was the 3-4 Band, not the clutch pack. Sorry for not clarifying, it was late......clutch pack....band....they are both intended to hold pressure, easily confused lol.
On the HD Shift Valve, what I said was when in D, or OD as some say, it has no effect on 3-4 Clutches. Yes I know it helps with 3-4 clutches in 3rd (D3). I said in the first sentence of that it has no effect in D (OD), and only applies in D1/D2/D3.
On the HD Shift Valve, what I said was when in D, or OD as some say, it has no effect on 3-4 Clutches. Yes I know it helps with 3-4 clutches in 3rd (D3). I said in the first sentence of that it has no effect in D (OD), and only applies in D1/D2/D3.
Last edited by 07NBSChevy; May 27, 2017 at 06:05 AM.
Making the modifications to the steel spring retainer as TransGo does in their regular Shift kit, will help on the downshift clunks
Staging Lane
Joined: Jul 2016
Posts: 53
Likes: 0
I'm certainly not a pro, but this is what I did. Since I didn't want drill shavings in the valve body, I used wire cutters to notch a "V" into the wall. I compared the size to a 1/8" drill to make sure it was big enough. I've done this to several transmission that I tested and it worked. You can tell that the 2-3 shift valve is installed because with the shifter in [D3], the 3-2 downshift is quite abrupt since the overrun clutch stays engaged.
I'd really appreciate it if you had a valve body like this lying around or explain on a picture.
On The Tree
Joined: Jun 2015
Posts: 113
Likes: 12
From: Hopewell Junction NY
to do with overrun clutch applied. I took it
apart again then drilled it with the specified drill bit . Now I felt the difference on the downshifts like it was supposed to ! Do yourself a favor do it right
the first time with drill bit. Just blow
out shavings with brake clean and a air blow gun.