I have a 1997 2500 auto 4x4 268k miles that was dumping fuel in its oil. Injectors and injection pump were tested and the injection pump was ruled to be the cause. Got a great deal on a 215hp p7100 pump and had that installed. Truck ran amazing for the first drive but after it worked up I started having shifting issues. Trans has had recent work in the last 10k miles. That "rebuild" was done before I purchased it so I don't know exactly what's in there.

Pump is a 215 hp brand new p pump timed at 18 degrees. Idle was set to about 750 to 800 rpm. The truck does not have ac so i wasnt able to set it with that on. We just matched the idle position from the previous 170 hp pump.

The transmission wasn't really having issues before I changed the pump. we messed with the throttle cable and we noticed the issue got better but wasn't completely resolved. The truck seems to shift 1-2-3 immediately, then 4 delayed and then slips in and out of OD. The OD switch still kills OD if it is engaged

It also recently got pretty cold. Lately ist been 10-17 degrees.

we initially noticed the cable was extremely tight so we loosened it which created the initial improvement, further loosening it put us at square 1. Same issue. Then we went back and coukd not replicate the progress we made in the first place. The only thing that was done to the transmission by me before this was re sealing the pan gasket andrepairing a leak at the the dipstick tube with silicone at the top of the boot. While the pan was off I replaced the filter and didn't see any nasty particles in it. There was some material on the magnet. All fluid was red and not burnt in any way.

Is there something I am missing? Trans worked fine before this. I just want to rule out anything before I dig into the transmission.

Pulling in from the test drive the truck died twice while turning. Do I have the idle set too low? I have no idea if there would be a difference between idle position from the 170 to 215 hp pump. Is there any risk of damage by increasing the idle?

 

I would spend some time adjusting your kick down cable first. Rule that out first.
Check the factory specs. for setting it.

Bump the idle up a bit and see if it helps with the stalling.

The 1997 auto came with the 180 HP pump.

 

All the suggestions above, plus:

Are you sure it's hunting for OD and not TCC-lockup?

I'd ask the shop if they scanned the TPS for dropouts with a graphing multimeter/scope - a bad TPS or bad wiring will cause problems. Check the bellcrank bushings for play - warn bushings that allow side play on any axis can kill the TPS.