I have a 2000 Chevy Trailblazer 4x4, just recently I lost my reverse totally but it shift well when I put it in drive. The truck runs great what can I do to fix this problem myself? I'm a little mechanically inclined, but have never worked on transmissions.
So, the first most important thing is knowing which transmission you have. Assuming it's stock, you have a GM 4l60e trans. (I just did some work on one of these last night so this piqued my interest.)
Doing a little Google-sleuthing, I found that this is a VERY common problem with this trans apparently, so the good news is it shouldn't be hard to find a lot of information about it. The bad news, based on 1 thread on a different site I found right off the bat, it sounds like you'll have to dig into the transmission.
So, unless you're VERY confident, or down-time for the vehicle isn't an issue, you'd probably want to take it to a pro. As a note, this becomes very difficult if you don't have the right tools!
On the 4l60e, I haven't been able to find anything relating to "reverse servos" or reverse shift solenoids or anything like that.
What You Can Check...
Based on one thing I found, it is possible that the Pressure Plate (which is mounted on top of the Transmission Valve Body) being loose will cause this issue. To check that you just have to:
- Drain your ATF.
- Drop the Trans Pan.
- Remove ATF filter.
- Check that all 5 bolts are good and tight.
- Thoroughly clean out the inside of the Trans Pan and both gasket mating surfaces! (NOTE: there is also a magnet in the pan to collect metal debris. Make sure to remove everything that's stuck to it.)
- Replace trans pan gasket.
- Replace ATF filter (technically that's optional, but it's not expensive and if you've got the pan open, you may as well replace it).
- Close Trans Pan. (NOTE: Take a moment to make sure that there are NO pieces of motor funk or debris of any kind inside the pan! It could work it's way into your valve body and cause some of the valves or pistons to stick thus creating new problems.)
- Refill with proper load of ATF (should be 7 quarts, but you can refer to your manual or do a quick check to verify.
You can check the shifter linkage just for the heck of it, but I doubt it's that if your only trouble is with reverse.
Most data I found points to teflon seals going bad in/on/around the reverse drum inside the trans.
Hopefully this gives you enough info to make the decision that's best for you. ;)