Hi all, New to this forum. 94 GMC with crate 5.7/auto/4x4
Driving to work my truck started slowing down while maintaining rpm. I finally downshifted into 2nd and was able to speed up for 1/2 mile then it started losing speed. Finally downshifted into 1st and was able to speed up for another 1/2 mile or so. Then it slowed down and I coasted to side of road. Uh oh, I noticed I had it in 4H. I tried 4L, 2x4 & 4H and truck would not move forward or back. Max speed was 60 on dry asphalt. Checked tranny fluid. Right on the mark, no smell, no grit.
About 10 hours later, I check the fluid waiting on my trailer to show up. it was way up. I'm guessing maybe a quart?
Off the trailer sitting at home, I ran through all the gears. I did hear a little grinding when I put it in reverse.
Questions:
1) Can the torque converter go bad and leak fluid into the tranny? (Where did the extra fluid come from?)
2) Rock Auto has pretty good prices on trannys, has anyone ever tried them?
3) Has to be either tranny or torque converter, right? Transfer case either works or it doesn't...
TIA for any ideas,
WizarDave

 

The torque converter can brain back. The most that could ever drain back is about half what the TC can hold which would register additional fluid on the dipstick.

If it was me, I'd open the trans up and inspect. They aren't as complicated and you'd think and there are complete teardown and rebuild videos on youtube for all the widely used models of transmissions out there.