My tranny oil and filter was changed at 160,000 on my 01 4.8 because you could hear the filter working extra hard. It made a sucking sound. 4 days later it started slipping and now it's slipping all gears. if you go a few blocks it wont catch anything at all. But if you turn if off and on again it will catch first gear. I'm planning on buying a new tranny but if you have any suggestions on why it's doing what it's doing and you have a better and less expensive way to fix it please let me know. I can't go much longer with out driving my truck. I miss the hell out of it already.

 

ok, i am quite positive i know what's going on.
fluid pain is total pain in *** to be removed on those. at the rear of it, there are some electronics with wet contacts, forgot what the hack the name is, but contacts are very easy to fall off from slightest touch. that inevitably happens when they reinstall the pan, AS THEY HAD TO TAKE IT OFF to replace filter. so, what's new, they rushed, did not pay attention, contacts are off, you have trouble.
i'll try to find a post with picture on this, just need time, i am member in 4 chevy forums, need to figure out which one is it.
if i were you, i'd go to dealeship, pull pic of that trannie with pan removed, and locate those contacts. so you know what to talk about to your repair boys.

got it!! 'ts called shift solenoids, you can see them - white pieces, with arrows pointing at them - on this page

http://images.google.com/imgres?imgu...%3D2%26hl%3Den

 

Could it be they are just loose?

 

I'm pretty sure i have a 4l60e but how can i check if its not a 4l80e? I'll definately look into the shift solenoids but Any more help before i take this bad boy apart???

 

Damn bro, you saved me alot of money. Hit the nail right on the head with those solenoids....besides that dexron VI running about $80/case....