Ok in the interest of getting my son some seat time before the end of the season, we grabbed the trans out of my car, since it's sitting with a broken rod that we haven't gotten to tearing apart.

Only thing we changed is converter.
All detents are perfect aligned with the shift cable.
Park, low gear, high gear and neutral are fine. Trans brake works fine and launches the car as it should.
But put it in reverse, and hit the button, the tires quiver like it went into gear, but the tires won't move. On the stand I can't even push them backwards. Turn the engine off, and the tires rotate backwards fine. No brake drag or anything.
It will go backwards if you give it a bunch of throttle, but stops immediately if if you let off the throttle.
This damn thing came out of my car working fine the round before.
Then an odd thing, his finger slipped off the button as we were backing it up to put on the trailer, and he kinda double hit it. Suddenly it backs up as it should with no drag.
At this point I'm convinced someone is messin with me. LOL. What could this be?

Did the motor lock up for an instant ( look at data recorders) when the motor broke? I’ve see this take out the trans and converter.

Make a jumper wire from the pan bolt you have the solenoid grounded, to the ground post on the battery.

Check the pressure at the reverse tap with, and without the jumper.

quote:

Originally posted by stk 758 BP!:
Did the motor lock up for an instant ( look at data recorders) when the motor broke? I’ve see this take out the trans and converter.

Well I don't see it, but it could have. But mostly the trans works.

quote:

Originally posted by Mike Rietow:
Make a jumper wire from the pan bolt you have the solenoid grounded, to the ground post on the battery.

Check the pressure at the reverse tap with, and without the jumper.

Would this be any different than simply making sure the plunnger is going flush with the solenoid body? By eye, it seems to pull in fine.
It's plausible though. The double hit then working was telling in that way. I always ground to the battery....except in his car which already had a chassis post right there. So.....well maybe.

planetary from broken motor ??????

Servo pressures/Reverse pressure? May be a cracked reverse pressure plate. long shot.

Torn gasket in the valve body?

quote:

Originally posted by Bucky:

quote:

Originally posted by Mike Rietow:
Make a jumper wire from the pan bolt you have the solenoid grounded, to the ground post on the battery.

Check the pressure at the reverse tap with, and without the jumper.

Would this be any different than simply making sure the plunnger is going flush with the solenoid body? By eye, it seems to pull in fine.
It's plausible though. The double hit then working was telling in that way. I always ground to the battery....except in his car which already had a chassis post right there. So.....well maybe.

Bingo!

Is the line lock hooked up to come on with the trans brake also. I have a car that does the exact same thing. When he came off the button he probably was not on the brake pedal and released the pressure.

quote:

Originally posted by scblback:
Is the line lock hooked up to come on with the trans brake also. I have a car that does the exact same thing. When he came off the button he probably was not on the brake pedal and released the pressure.

Ummm.
Man as stupid as this is, I think you just made me think of what it is. I didn't rewire this car, and it indeed has a line lock. I would be willing to bet anything that this is where the problem lies. I have never had a line lock in a dragster and never gave it a thought.
Thanks for pointing out the obvious.