94 Caravan shudders before it moves

A Friend of mine has a 94 caravan with 3.3 and overdrive. He took the internals out of one case and replaced them into another. The first trans wouldn't do anything. 138K on vehicle. The second trans will go into reverse and move fine. It will go into drive but must rev it up to move. It shudders while it tries to move. Eventually it will move and shift.
Any ideas?

Thanks

There are too many possibilities:

Wrong fluid.
improperly installed seals, pump (anything)
Bands bad.
Bad pump.
clogged cooler or cooler lines.

This was a notorious No-no. What was replaced with new parts?

He replaced the solenoids, now it shifts. I asked him which fluid he put in it. He used Dexron. I told him to flush it and replace it with ATF 3. He said he didn't care, there was no warranty. I guess I won't let him work on my vehicles.
Thanks for the reply.

The dexron killed you.

The rebuild kits are actually pretty cheap, not really worth swapping the guts around. But, if you're lucky, putting the +3 in it will give you a long lease on your/his tranny's life.

not caring is why so many mechanics and shops get to be hated.

Good luck,

Slantsixness

I used to always want to be a mechanic in a shop, but I realized that I wouldn't be able to sleep at night from robbing people all day, every day. I just wouldn't be able to do that.

If you mess up on your own vehicle, you become a mechanic's meal ticket. It's sad but it's true.

You should take precautions and good advice whenever you can.