A4LD probs. after rebuild

[powerplantranger]

Here's the truck:

88 Ranger 4x4
2.9 135k org.
A4LD auto

Lost the tranny in June. Took it to the shop to get it fixed. Went to get it, it still wouldn't shift right. Left it there they fixed it. Picked it back up, took it home and used it around the farm. One day it went to put it into drive and nothing. Wouldn't shift into any gear. Rev'd the engine to 4k and it softly shifted into gear. It did this for a couple weeks, every time it did this it was cold or hot, it didn't matter. Finally called the shop to come and get it. I went to move it for the wrecker and it shifted fine . The shop said it was fine , as they put over 100 miles on it over a few days. I was gonna pick it up and they called me telling me it started acting up, and that it was the engine. I called B.S on that, the engine is perfect. Any idea's on what they might've missed or not done? They told me for the rebuild they replaced all the hard parts too.

The one thing that I did notice during those few weeks is when I took it down the road it almost seemed to bog down and shimmy a little, like it was in the wrong gear...

Thanks..

MAKG I know you might have an idea....

 

[Bent Bolt]

No engagement unless reving the engine means a low line pressure issue. Could be many things. Broken/missing O-rings on the filter, worn/damaged pump assy, stuck pressure regulator valve, wrong valve body gaskets, broken/damaged sealing rings. Also a failed torque converter CAN do sort of the same thing but not magically "cure" itself. A sticky valve can have the same symptom.