This is a new one. Now that I've got the truck back up and running, she doesn't want to go into gear until warmed up.

It's a rebuilt transmission, it did sit for a couple of years while I had to hunt down that flexplate.

So, it's a baby 904 automatic, fluid levels are perfect (checked on a level surface, engine at operating temperature, transmission in neutral). Brand new fluid, brand new filter, brand new torque converter.

The truck does sit on an incline on my driveway, the ass end is lower than the front...

Once she warms up and I can get going, the transmission shifts just as smooth as can be.

Any ideas?