Will not go into 1st while in Drive but will manually
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Staging Lane
Joined: Dec 2013
Posts: 59
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Will not go into 1st while in Drive but will manually I recently ordered a kit from Dana @ probuilt and me and a friend who does transmission rebuilds for a living rebuilt my 4L60E out of my 96' LT1 Camaro. Ran great for about a month then I got a code for an electrical hard fault on solenoid B, threw a code and trans went into limp mode, OK so I guess the solenoid failure is to be expected (factory solenoids on 190k car). Replaced both solenoids and soon figured out I forgot the spring and .265 check ball that goes inside of the hollow 1-2 valve that comes in the trans-go hd2 kits when I saw it on the drip tray. Car wouldn't go into 1st on its own when put into drive, it would go into 2nd. Ok I guess that's to be expected also because when you leave a big hole open in the middle of the valve there's nothing to build pressure on and shift it. So I popped the pan off again and put both the spring and ball back in place. Now heres where it gets weird, its still doing the same thing.... In drive from a dead stop I push the pedal down and it starts to take off but If I quickly shift down to 1st I can feel 1st gear engage and it starts to take off with a lot more pep in its step and I can shift through all the gears manually.. 2nd, 3rd, 4th, lockup they all work great. Am I missing a key piece of information or something or is this not supposed to be happening? Possibly TPS plays a role in selecting 1st or 2nd gear from a dead stop? I was almost certain its supposed to take off in 1st though. If anyone knows im here to listen. Ill use the scanner on it tomorrow and engage the solenoids manually and see what happens but for now I dont want to look at the thing lol. If that pan has to come off again I might blow a gasket lol
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Joined: Aug 2010
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From: Ann Arbor, MI
Some PCMs will start the car in 2nd gear if the shifter is in [D2]; I don't know about LT1 PCMs.
But it should always start in 1st gear with the selector in [D3] and [D4].
Personally I see no good purpose for the "Gear Command" feature of the Transgo HD2 kit; I only see a huge danger of it letting you downshift too far and overrev the engine. So I always leave those parts out. My car/trans also downshifts instantly without it. The "hollow 1-2 valve" you mention is the Gear Command feature.
Therefore, I would suggest removing the hollow 1-2 valve (with the check ball and outer spring) and putting the stock 1-2 shift valve back in. (You reuse the spring under the shift valve.) If you no longer have the stock valve, I probably have a spare to send you.
But it should always start in 1st gear with the selector in [D3] and [D4].
Personally I see no good purpose for the "Gear Command" feature of the Transgo HD2 kit; I only see a huge danger of it letting you downshift too far and overrev the engine. So I always leave those parts out. My car/trans also downshifts instantly without it. The "hollow 1-2 valve" you mention is the Gear Command feature.
Therefore, I would suggest removing the hollow 1-2 valve (with the check ball and outer spring) and putting the stock 1-2 shift valve back in. (You reuse the spring under the shift valve.) If you no longer have the stock valve, I probably have a spare to send you.
Thread Starter
Staging Lane
Joined: Dec 2013
Posts: 59
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Thanks for the response. I too was weary about the function of the hollow 1-2 shift valve after I put it in seeing how easily it is to make a mistake like that with a stock shifter. The guy who I built my transmission with said he beleives he might have thrown out my 1-2 valve but is confident he has a couple extra 4l60 valve bodies laying around and would be willing to trade me my hollow one for a good looking solid valve out of a stock valve body. If he happens not to have one ill definitely let you know. I really appreciate the offer. Id love for this to be the last time I have to take that godforsaken pan down so when I get time today im going to go out with the scanner and make sure all the solenoids are functioning the way they should and everything else looks good in hope of eliminating all other possible reasons this things not wanting to go into first for me. This car is a headache lol, currently trying to get it ready to sell and every time I fix one thing I end up with another problem lol
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Joined: Aug 2010
Posts: 7,323
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From: Ann Arbor, MI
Glad you concur to just put the stock 1-2 shift valve back in. Let me know if you need the valve (no charge, just shipping if you want it overnight).
You have obviously learned a lot about automatic transmissions; it may be useful knowledge some day.
You have obviously learned a lot about automatic transmissions; it may be useful knowledge some day.
Thread Starter
Staging Lane
Joined: Dec 2013
Posts: 59
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Had the scanner hooked up Saturday watching for shift commands and what not and how the solenoids where switching on/off and got on down the road and the 3-4 clutch pack I believe is fried. 100% slippage in 3rd and 4th. A little upset at first but its life and that's these things go... nothing new to me lol. It could be possible the 3-4 piston was cut during installation we did however check the clearance given by dana so I can atleast say I did something right lol. Anyway hoping to pull it out sometime this week and have a look. Would you think think it'd be a bad Idea to only tear the trans down far enough to verify nothing else is torn up and replace the 3-4 steels and fibers only? My logic was there is no sense in fixing anything else that doesn't need to be fixed considering it has less than 500 miles on a fresh build.
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Joined: Aug 2010
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From: Ann Arbor, MI
Besides the 3/4 clutch piston that you mentioned, there are many other places the 3/4 fluid can leak:
1. 3rd accumulator check ball capsule - in the case "under" the servo
2. Seal on the 2nd gear servo piston
3. The pump halves - i.e. if the pump got warped
4. The teflon rings on the input shaft
5. Looseness between the input shaft and drum
6. Leakage in the input drum bleed hole or the check ball for the 3/4 clutch
7. And of course the 3/4 clutch piston seal
Many/most builders replace the 3rd accumulator check ball capsule with every rebuild.
For high RPM operation many builders remove the check ball in the input drum (for the 3/4 clutch) and replace it with a simple orifice capsule.
When you open the trans and before you disassemble the input drum, I suggest doing an air test to help locate any leak:
1. Support the pump upside down in a sturdy cardboard box or vice.
2. Install the input drum (without the reverse drum) into the pump.
3. Air test the various clutches with a rubber tipped blow gun into the feed holes in the pump. The 3/4 clutch is the angled feed hole.
A little bit of leaking in the 3/4 clutch is normal due to the bleed hole(s) in the input drum, but you should still get solid engagement.
Regardless of what the problem turns out to be, remember to repeat this air test on final assembly.
I don't have the experience to answer your question about whether the entire trans should be opened and cleaned; it may depend upon how much friction material there is in the fluid. I posted once that it probably wasn't necessary to open the entire trans and a pro builder scolded me for giving bad advice and that excessive friction material can clog the valve body and other passages.
So, it might depend upon what you find. Perhaps the leak is so bad that 3/4 clutch frictions never engaged and wore out.
1. 3rd accumulator check ball capsule - in the case "under" the servo
2. Seal on the 2nd gear servo piston
3. The pump halves - i.e. if the pump got warped
4. The teflon rings on the input shaft
5. Looseness between the input shaft and drum
6. Leakage in the input drum bleed hole or the check ball for the 3/4 clutch
7. And of course the 3/4 clutch piston seal
Many/most builders replace the 3rd accumulator check ball capsule with every rebuild.
For high RPM operation many builders remove the check ball in the input drum (for the 3/4 clutch) and replace it with a simple orifice capsule.
When you open the trans and before you disassemble the input drum, I suggest doing an air test to help locate any leak:
1. Support the pump upside down in a sturdy cardboard box or vice.
2. Install the input drum (without the reverse drum) into the pump.
3. Air test the various clutches with a rubber tipped blow gun into the feed holes in the pump. The 3/4 clutch is the angled feed hole.
A little bit of leaking in the 3/4 clutch is normal due to the bleed hole(s) in the input drum, but you should still get solid engagement.
Regardless of what the problem turns out to be, remember to repeat this air test on final assembly.
I don't have the experience to answer your question about whether the entire trans should be opened and cleaned; it may depend upon how much friction material there is in the fluid. I posted once that it probably wasn't necessary to open the entire trans and a pro builder scolded me for giving bad advice and that excessive friction material can clog the valve body and other passages.
So, it might depend upon what you find. Perhaps the leak is so bad that 3/4 clutch frictions never engaged and wore out.
Thread Starter
Staging Lane
Joined: Dec 2013
Posts: 59
Likes: 0
Thanks for all the advice. I completely overlooked all the other places it could be leaking thanks for reminding me. I remember during the build we did replace the check ball with the orifice. Ill hopefully get the transmission torn out of the car sometime this week and ill do the initial air checking to try and find a leak and also inspect it a little bit before I tear it down. Ill try and post a few pics if I remember to take some of what I find. Thanks for the help and listing all the places to check for leaks, I really appreciate it.
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TECH Resident
Joined: May 2006
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As long as you have the TransGo 1-2 shift valve assembled correctly, changing it back to stock valve is just a waste of time as it will change nothing except the ability to hold manual low to any rpm or being able to go back to first anytime you want. Put a 0 - 300 psi. gauge on it and see what the pressures are before you tear it down so that we can see if there or where there is a "pressure loss", that way we can solve the problem correctly. Correct pressures are 220 - 240 psi. at WOT in "1" or "2" at above 3,500rpm. If the pressures are "down" and the TransGo Shift kit was installed correctly, then the EPC solenoid needs to be adjusted to get the right pressures. I will help you out on what you need, just do the pressure test to see what is needed here exactly. Once the pressure test is done, call me if you can as that would be best to sort this out on what needs to be done.
Thread Starter
Staging Lane
Joined: Dec 2013
Posts: 59
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Ill let you know tomorrow. Ive got to pick up a couple NPT fittings for my LQ9 so I can bench test oil pressure to verify its in good health, while im there Ill pick up a 0-500 gauge a 1/8-27 fitting to test the trans. How do I test it exactly? You said at WOT do I need to run the gauge inside the car and drive it?
Moderator
Joined: Aug 2010
Posts: 7,323
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From: Ann Arbor, MI
The trans pressure gauge sold on ebay for $40 includes a 6ft hose so that you can hang the gage near your side mirror on even on the windshield to monitor pressure while you drive.
However a lot can be checked without driving the car.
In Park or Neutral: Pressure with a shift kit/boost valve should be 75-90 psi.
In Reverse: The pressure should jump to around 175 psi
Blip the throttle: pressure should jump to around 200-225 psi.
(I don't know if you can blip the throttle in Park or have to be in Drive; my car is very custom.)
However a lot can be checked without driving the car.
In Park or Neutral: Pressure with a shift kit/boost valve should be 75-90 psi.
In Reverse: The pressure should jump to around 175 psi
Blip the throttle: pressure should jump to around 200-225 psi.
(I don't know if you can blip the throttle in Park or have to be in Drive; my car is very custom.)
Thread Starter
Staging Lane
Joined: Dec 2013
Posts: 59
Likes: 0
I'm on the fence about removing the trans. I cant seem to find a gauge locally and I'm running out of time, I need to hurry up and get the car sold. Will pressure testing it help me drastically pinpoint the internal leak? If so Ill hold on a little longer. Both times I removed my pan to play with the 1-2 valve there was a substantial amount of clutch material in the pan so I'm almost positive the 3-4 clutch pack is the culprit. The hard part is going to be figuring out why it failed.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
You started this thread by reporting a problem starting in 1st gear; then you said that the 3/4 clutch was slipping. Both could be related to very low line pressure. If line pressure if good, then you know you have a leak in the 3/4 clutch circuit as I detailed above. However, if you do NOT know if line pressure is low, the builder will be less sure what problem to look for.
Just a wild thought:
Here are the Transgo HD2 instructions:
https://ls1tech.com/forums/automatic...questions.html
Look at Step 1 on Page 4. Notice it mentions an "Alum Spacer" on the boost valve. This must be installed on '95 ('94?) thru '05 transmissions (before ISS). If left out, line pressure will be very low and you might have slippage in all gears.
When the pan is off, it only takes a few minutes with a snap ring plier to remove, inspect and re-install the boost valve to ensure it was assembled correctly.
A gauge would quickly let you check that the boost valve was working properly. Or just take it to a trans shop and let them check it. A combination of a pressure gauge and good scanner lets you pinpoint trans problems.
Just a wild thought:
Here are the Transgo HD2 instructions:
https://ls1tech.com/forums/automatic...questions.html
Look at Step 1 on Page 4. Notice it mentions an "Alum Spacer" on the boost valve. This must be installed on '95 ('94?) thru '05 transmissions (before ISS). If left out, line pressure will be very low and you might have slippage in all gears.
When the pan is off, it only takes a few minutes with a snap ring plier to remove, inspect and re-install the boost valve to ensure it was assembled correctly.
A gauge would quickly let you check that the boost valve was working properly. Or just take it to a trans shop and let them check it. A combination of a pressure gauge and good scanner lets you pinpoint trans problems.
Thread Starter
Staging Lane
Joined: Dec 2013
Posts: 59
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Okay Im with you. Ill check the line pressure first. Sorry about jumping around subjects I just want this thing gone and Im a little pissed off... Ill report back with what I find out. Thank you guys for your help even as fked up as this whole thread is...
Thread Starter
Staging Lane
Joined: Dec 2013
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Okay I hooked up the pressure tester today and heres what I got:
In P,N,D,3,2,1 @ Idle 70psi
90psi @ idle in reverse
In park with a quick blip of the throttle to about 400rpm the gauge spiked to about 150psi.
I didnt have much time and I live in a neighborhood and get off work @ 8pm so it was a little late to be making too much racket. Its the best I could do and I hope the readings might be able to help figure out whats wrong. Once again thank you guys for helping me out.
In P,N,D,3,2,1 @ Idle 70psi
90psi @ idle in reverse
In park with a quick blip of the throttle to about 400rpm the gauge spiked to about 150psi.
I didnt have much time and I live in a neighborhood and get off work @ 8pm so it was a little late to be making too much racket. Its the best I could do and I hope the readings might be able to help figure out whats wrong. Once again thank you guys for helping me out.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Reverse is too low. Reverse fluid pushes on the boost valve to significantly increase pressure. Good that it raises with the throttle; it indicates the EPS (pressure control solenoid or PCS) is working and much more.
Hate to ask you to drop the pan again, but I do suggest looking for that spacer on the boost valve. I think a missing spacer would give you that low Reverse pressure.
Maybe PBA or one of the other builders will chime in here as they each have 1000x more experience than me.
Hate to ask you to drop the pan again, but I do suggest looking for that spacer on the boost valve. I think a missing spacer would give you that low Reverse pressure.
Maybe PBA or one of the other builders will chime in here as they each have 1000x more experience than me.
Thread Starter
Staging Lane
Joined: Dec 2013
Posts: 59
Likes: 0
Its alright dropping the pan is no biggie at this point. Like I said in an earlier post, it no longer has 3rd or 4th gear so a trans removal is necessary to rebuild. Ill definately have a look at the boost valve assy when I take the pump out and refer back to the trans go specs on the spacer and parts, use a micrometer and mesaure it and make sure everything is the right size. I think at this point what I'm planning on doing is removing the trans and find the source of the pressure leak going to the 3-4 pack covering all the spots you mentioned before. My friend who helped me build the trans has 10s of years of experience rebuilding transmissions and since hes a good buddy of mine Im sure he wont mind helping find out what went wrong and helping me fix it. Im interested to see what his stand point is on a complete rebuild vs just a tear down and inspection and reusing all good parts and only replacing whats wrong.