I've got a beefed up 4l60E. Is it normal for the tranny to thump real hard when down shifting into 1st while coming to a stop? It's a pretty solid thump. Or is this a sign the tranny is going to take a dump?

Also, I've noticed that while city driving, my tranny will sometimes stay stuck in 2nd gear. I have to pull over and let it cool off for about 10 minutes so it'll work right again. BTW, I'm running a PT4000.

 

1 have you tuned for the stall , Checked for codes,
those were questions rekating to the 2nd gear.
What servo set up is in the car?
does it do this clunk just in D or in overdrive or manually, manually it certainly should.

 

Sounds like it isn't tuned properly and may possibly be low on fluid. Similar happened to me and had to get the tune fixed.

 

I would have a tuner look at that quickly! If this pursists, you will lose the teeth off the forward clutches.

 

Yes it's tuned. Unfortunately I'm not sure what servos are in there. It'll thump going into 1st right before I come to a complete stop in "D".

 

That problem exsisted in the 700R4 where the servo needed to be grounded to the bevel inside the servo, (about 3/16ths"). The 4L60E never had this problem. It will be interesting to see what causes this in your trans.

 

I'll keep you posted as soon as my tuner hooks up the lappy!