Trans slips only when warm

[are_one]

I performed a search, and no matches were found. Well the transmission shifts through all gears just fine as long as Im not stuck in traffic. When I sit in traffic for a while the problems start. 1st to 2nd slips (it feels like its shifting twice, it goes bump, bump then shifts), and the same for 2nd to 3rd. I have a shift kit in it that always shifts hard, but this problem just showed up recently. It will act like this until I shut it off and let it sit for a few hours. I installed a trans cooler, but this didn't seem to help. Any ideas???

 

[A. G. Olphart]

Any slipping is killing your tranny. One hard run with slippage has been known to do the job.

Temperature sensitivity can relate to loose pump clearances; the fluid gets thinner when warm, so pressures drop. I guess you could try a new filter and fluid, but in all likelihood you are due for a rebuild. (They are cheaper sooner than later).

 

[A. G. Olphart]

Came back to edit/delete the above- too late.
Maybe one of the experts will have an idea... I'll stick by the pressure drop due to thinning fluid, but haven't a clue where your leak might be- any seal or gasket.. Sorry.

 

[are_one]

Thanks for the reply. I went to change the filter (thanks buick for not installing a drain plug), and one of my pan bolts broke off. Everything was very clean, I figured since it was rebuilt when I bought it, maybe the filter was dirty, but it wasn't. What baffles me is it only happens after I've been sitting, and creeping through traffics, if it did it all the time I would know the trans is definatly bad. I don't know if it could be classified as a slip, its more like a missing the gear than catching it when shifting.

 

[IrvJr]

Are you overfilling the trans so it has that extra fluid above the top feeding trans filter under acceleration? Mine did things like that when i didnt have enough overfill to compensate. I recently changed to a bottom feeding 700r4 filter and it made a huge difference in the way the car shifts and best of all no more overfilling.

Scott

 

[are_one]

Originally posted by IrvJr
Are you overfilling the trans so it has that extra fluid above the top feeding trans filter under acceleration? Mine did things like that when i didnt have enough overfill to compensate. I recently changed to a bottom feeding 700r4 filter and it made a huge difference in the way the car shifts and best of all no more overfilling.

Scott

Dammit, thats a pretty good idea. Unfortunately, I went and filled it back up. You should have heard the profanity I was spewing when the pan wouldn't mate back up. Come to find out the rubber grommet from the old filter was jammed up in the neck hole. Always something...

 

[IrvJr]

Yep always something, at least that wont happen to you again. Now you know to look before you put the new filter in.

Scott