2002 Silverado 2500 HD trans wont go forward but reverse works

Brent Belt · May 8, 2020

Hey guys my truck has over 500,000 miles and recently the transmission has been messing up in the forward gears. It started as when it was cooler outside it would hesitate to go forward until it warmed up a few minutes. I drained the fluid and changed the filter and it seemed to be working great for a while. A few weeks ago I parked it on a hill and the next day it would move forward yet reverse works fine. Note...I drained the fluid out of the pan again and went to put some in and could only get maybe 2 quarts before it showed full...? Any ideas? Thanks

vucelick · May 9, 2020

Most transmissions would not make it 500,000 miles without needing a rebuild.

David89GMC · May 14, 2020

Agreed, it needs a rebuild. Any number of things can cause this, solenoids, clogged passages, others...

Your best option is to buy a new transmission from GM. Rebuilds are a crap shoot and I can't recommend a rebuilder for you. There are great rebuilders, but you'll need to find one that doesn't skip any steps. It costs a lot for a correct rebuild, like $2500.

davester · May 14, 2020

I completely disagree with buying a new transmission. Lots of places can rebuild them just fine, and it doesn't cost a lot, unless you want to rebuild it to support more power (which it doesn't sound like you want to do). And with the 4l80e, at least with the transmission shops around here, it goes quick in that they swap your 4l80e for one that's been rebuilt and you are on your way, and then they rebuild your transmission and put it in the next persons vehicle.

Hell, I've rebuilt my 4l80e myself, having never done any transmission work other than dropping the pan and changing the fluid/filter, and it works fine after 80k km. Now, it's not a job for everyone, I have a fair amount of experience working on engines, have a pretty well stocked garage with tools, and lucked into finding the tools for doing the various lip seals (in particular the OD seals), and teflon seals, so I'm not recommending you do it yourself without you researching it yourself if it's in your wheelhouse...