I overhauled a TH200c for a buddy of mine for his nephews Cutlass. I've done several different auto trans with no problems. I like to think I pay close attention to detail. He called me tonight to let me know they finally fired up the Cutlass and while on blocks all forward gears seem fine but when put into reverse the tires barely turn even though you can hear it lug the motor down some. He feels as though something with reverse is "binding up". He did have to remove and re-install the pan because of some sawdust that went astray and the dipstick tube not in place before it was put back into the car. Could something on the manual valve be knocked loose? Maybe some other issue? Any feedback on this would be great.

 

What do the ATSG and GM manuals suggest? Or did you "wing it"?

 

Still looking for help with this. All forward gears fine, upshifts are fine, downshifts are fine with engine braking. Manual shifting is just fine. Reverse lugs the engine down a bit like it's going into gear but no real torque being transmitted to the tires. Removed valve body and went through it with a fine tooth comb, everything A-OK. What's wrong here?

 

Line pressure in all gears is correct according to the STSG manual. Pulling the trans out to tear back into and find out what I screwed up. Must have bent a lip seal or something.

 

I'm not a rebuilder but did you touch the boost valve in the pump?

Perhaps this comparing apples to oranges, but I did a 4L60E and didn't get the boost valve snap ring in the pump all the way which caused the valve to partially exit the pump. Had all forward gears but no reverse. Luckily, getting the valve back only required dropping the pan.

 

Boost valve is just fine. Pressure check confirmed that.

 

Same thing happened to my friend after rebuilding his 700r4. Boost valve in the pump wasn't in far enough. There was a second ridge further in for the snap ring to hold and it was only in the first one. Had all forward gears but no reverse.

 

Fixed it, I had accidentally swapped a spacer ring and snap ring allowing too much clearance in the reverse pack.