Trans shifting

Guys,

Got a 98 Cherokee, auto, 4x4, 4.0. Bought it a couple weeks ago and it wasn't in as great of shape as I thought. Rebuilt engine/Trans/transfer case. Had a few trans codes (P0700, P0715, P0740) that I have since fixed. Cleaned the NSS and new TPS.

I'm having issues with it going from 3rd to overdrive around 45 mph at almost the same time. It shifts into 3rd then I can hear the engine drop rpm and gear, even when I'm lightly accelerating. Jeep has 31's also with 3.55 gears and it doesn't get up to speed too quickly. I have also adjusted the TV cable with no change in the 45mph shift. Other shifts seem normal. No engine codes.

Any other ideas?

I appreciate it

Does this happen when you are WOT, or heavy on the throttle? Or just "normal driving"?
What happens if you leave it in 3rd?

I have only really tried normal throttle. It doesn't seem like I will ever accelerate quicker with 31's and stock gearing. I will try some more skinny pedal. I forgot I have had an intermittent P0420 code, which maybe the cat could cause some lacking power? If I have a bad cat, I will just delete it

IMO, 31's and 3.55's suck. Ask me how I know.. Haha.
Anyways, your lack of power seems like a bigger issue than 31's with stock gears.

In 3rd at 45mph the TC can lock causing a slight rpm drop. Use a little more throttle and this will not happen.