4t60 delayed engagement sometimes

[thikstik]

My car is a 1994 3.8 regal and a freind of mine has a 94 Lumina 3.1. Mine sometimes has a lag before trans can pull away (only on first days pull away) . Im almost sure it is the convertor not getting charged with fluid fast enough, her Lumina has done it for years, but is so bad now that it can take 10 minutes to pull away, and now is always. I got an ATRA book on the 4t60 and i see that there is a thermostatic bi-metal valve (2 actually) . One of them regulates how much fluid is in side case depending on temp. So if its alittle off, maybe the fluid is getting pulled out of lower pan too much. It says that this trans will show HIGHER fluid when cold and that this is a function of the valve working. Im thinking about over filling alittle and see what happens. BTW, each car has very clean fluid so it cant be slipping clutches. I cant believe no-one else has seen this happen. thanks

[mfewtrail]

Delayed engagement(especially on cold-starts as you've described) is often caused by a partially plugged filter. Drop the pan on the transaxle, replace the filter, and refill the trans. It will take approximately 7qts of atf to refill the transaxle to the proper full level. Fluid level is properly checked w/ engine running + warmed up and the transaxle in "park."

 

Here's a writeup from an old member that details changing the transaxle fluid. The write-up is for a 1993 Grand Prix, but it and both vehicles you listed both have the same 4T60-E transaxle. http://www.butchthecat.com/past/gp/xmission.htm

[Crazy K]

I had this on a really really really bad 4t60 transmission in a 91 cutlass supreme. While I am not certain of what the issue was(pan drop did not fix, but showed the car was never serviced with lots of debris in the pan), whenever i wanted to move the car it had to either be pushed slightly in gear, or jacked up so a tire was off the ground and then placed in gear so the tire spun. Once the car moved slightly it would go fine as long as the transmission was warm after restarts.

[alec_b]

Had the same problem with my '91 regal. It always took a second to "pump up" before I could go anywhere otherwise it felt like it was slipping. Did this from the day I bought it until the day the pump went out completely, and after that the car could only be driven a few blocks before the fluid got too thin and it wouldn't move.

 

This all happened AFTER I changed the fluid twice and the filter twice.

[johnny404]

most of the time when you have a delayed apply of forward gears it is because the input clutch packs wont fill up enough to make the cluthes apply

there are many reasons for this sometimes its worn clutches sometimes its a cracked piston,piston seal,worn drum etc

the plugged filter will cause this but its easy to prove or disprove that just change it

it wont hurt and its a cheap way to rule it out

[thikstik]

Both cars have great fluid....i service both. Hers is getting worse with longer delays. Mine only does it once every few months or so...daily driven. i say it cant be friction material/clutch packs as they would be smoked easily with just a few seconds of slipping. And no dark matter in pans. I think i will over fill hers and see what itll do. I see that the forward band is on in in every gear except R. So if it doesnt slip in R it should be the forward band. But the input cltz are on up to d3, so no way to isolate them. Maybe its low apply pressure but that would still smoke frictions fairly fast. Since theres no darkness i still think tc is where the slip is...still not good, as that could be turbine shaft bearing, hard part, etc. Both cars shift perfectly with no slip once going. And there's no clunk whhen engagement occurs. thanks

[pshojo]

Did you ever figure out what your problem was?