Hi Everyone,
I just bought a 94 Trans Am on Sunday. I'm totally new to F bodies. The LT1 seems to run great but the (auto) transmission isn't working. If I put it in gear and rev up to 3000 rpm or so the car will start to creep slowly, works about the same in any gear, forward or reverse. I checked the fluid level with engine running and it was over full. I have no history on the vehicle, I bought it from a guy who got it in a trade and doesn't know anything about it either. He may have dumped in the extra fluid in an attempt to make it work, I'm not sure.
I'll have access to a lift next week and am planning to drop the pan and change the filter and obviously the fluid.
I'm no transmission expert, what should I look for when the pan is off?

Thank you in advance!

 

Burnt fluid and clutch material in the bottom of the pan.

 

I hope you got a good deal on it! If you plan to keep the car. Why bother changing the fluid & filter, pull the pan to check for debris. I'm fairly sure you'll find a lot. I might break open the filter to see how much debris is there. There are 2 major components that will cause that issue.
First is the torque converter being shot and it can no longer force the fluid to twist the turbine shaft.
Second the pup is shot and it can no longer pump the fluid to the converter or clutch's to move the car.
That's just me and a 2wd transmission of that year only takes about 30 minutes to get it out and to a bench.

 

Thanks. So how would I determine the condition of the pump and torque converter to see which one(s) is shot?

And the fresh fluid and filter was going to be out of a naive hope that the filter was simply blocked.

 

Removing the pan & draining the fluid is where I would start.The old filter can be split apart and the filter media inside can be separated and inspected. the 1/2 metal, 1/2 plastic ones are easier to open. Usually inside the pan is a magnet and the magnet will look like a chia pet if the converter or pump is damaged. If it's to bad opening the filter is a waste of time but curiosity sometime wins out...
Once the transmission is out it can be torn down and evaluated for damages. Having drained it helps to keep from making more of a mess from pulling a completely filled unit.

 

pop a cooler line off
start the car
if it starts puking fluid...the pump functions to some degree
if it dribbles...pump is broken just pull the trans and get it fixed

 

I've read that the 1994 4L60E is not interchangeable with later ones because it doesn't use PWM to control the lockup. I've also read the torque converter clutch itself is different, something about carbon fiber vs paper. Does this mean a replacement torque converter must be specific to the early 4L60E or will the later style torque converters (pre LS) work with the early transmission?

Edit: disregard, I found my answer here: https://ls1tech.com/forums/automatic...-material.html

 

Personally based on your description I would not even pull the pan unless to drain fluid for removal. I would just remove rebuild or replace trans and converter. |

 

Yeah, replacing the fluid would be a total waste of time and money. You obviously have plenty of fluid.
Follow MaroonMonster's suggestion for a quick test.
If you have access to it, a more accurate test is to connect a pressure gauge to the trans. It should give you 50psi+ in Park and 100psi+ in Reverse. Less and your pump is likely shot.
Yeah, the 1994 4L60e is an odd-ball year. A wide range of converters is available.

 

Yes the 94 is odd and gets even odder when you find some actually did have the PWM in the latter part of the year . However any of the later one piece case trans can be modified to work By sticking the converter regulator valve or installing the fitzall tcc fix valve. However, the 3-2 solenoid is also an issue some times. I say sometimes because sometimes the PCM is tolerant sometimes not, The impedance is different on the 93-94 and 95 units from later ones. Sometimes and sometimes not this sets an electrical code for the 3-2 and makes limp mode . Solutions are replace the harness and 3-2 solenoid to the earlier one, or optionally grind the slides off side of plug so the later harness will plug into earlier solenoid . In any case if you use a later one the pwm solenoid must remain in the slot even if not plugged in or used.
All the later model converters will work only the early ones would be an issue with the later trans, I would say it would be hard to find a converter with the early clutch lining anymore even if you tried.
Note also if you have CATSTUNER for the OBD1 you can just turn off the code for the 3-2 electrical and it will work fine this is how its set up in my own car as I used a late harness and solenoids in the build 1995 impala ss

 

Thanks everyone, I'm impressed by the knowledge on this site and glad to have it as a resource. So no chance the problem could be just a clogged filter? I purchased the car knowing the seller tried to drive it and transmission didn't work, which made it really cheap. My goal for the car is super low buck bracket racing. I have a th400 that I was planning to swap in. However, when we rolled it off the trailer and I tried it and got it to roll forward and backwards, I thought maybe that means there aren't any hard parts broken. It seemed like it was ​​​​​trying to work. I thought maybe the 29 year old filter is just clogged up (see, I know nothing about transmissions) and maybe I could start driving the thing now without having to swap the tranny. But if it probably needs a pump and torque converter, or if I need to pay someone's shop rate to fix it for me, then I should just proceed with "plan A". Instead of throwing any money at the 4L60E trying to figure out whats wrong, I'll just put that toward the crossmember and driveshaft work I'll need for the th400. Thanks

 

If the filter is clogged, what do you think clogged it. There are only a few things that could clog the filter and none of them are good. The lock-up clutch material from the torque converter or clutch material from worn out clutch packs. You can give it a try if you like but if it starts working it won't last long.

 

Thank you, that makes my decision easy. Th400 goes in the car, 4L60E core goes on craigslist.

You saved me money and effort on a lost cause.