90’ XJ 4.0 AW-4 33” tires trans fluid good

So I’ve just started noticing high rpms at highway speed and has led me to realize I’m not getting into 4th gear. I know it’s worked in the past having driven from Cali in 15’ with basically zero issues. (As of righting this, I ’m counting only three gears on a long stretch by time I hit 50 + mph. Fluttering brake or gas pedal don’t affect rpm.) Since then I’ve mostly used it for a daily with close distances so either the issue has been on goin*for a while or not, but not sure. About a mo. ago I cleaned out my NSS and only had an issue getting into D, like I needed to really pull it back to get it into pos. That issue worked its way out by itself in a day or two and selecting D now seems normal. All gear selections seem fine.

I’ve reviewed briefly the AW4 section in the FSM and tried the manual gear selection road test with the TCU unplugged and couldn’t tell a difference from 3rd and D. I also noticed, when selecting 1-2 the first two times I ran the test, it wasn’t actually being pulled far back enough. The third time I really pulled back and definitely got 1-2nthen.

So I’m getting good shifts In all gears but no 4th in D. Fluids at full, looks good, recently cleaned NSS, but reving 2k + rpms at highway speed.

Misaligned NSS? Can TPS be faulty like I’ve only read on forums? FS Manual points to electronic control problem, repair the valve body, replace faulty solenoid, or diss. An repair trans..... I can’t tear into the trans just yet until I swap motors in my plan B car, so .... yeah, stuck driving this. IF there’s a test to be conducted, please explain the resource, or method and expected outcome. I’m in Bradenton, FL all week and drive 3 hrs back East to fam on fri.

 

Trans computer disconnected and shifter in (D) you should be in 4th gear. If not, then likely a mechanical problem. If you had problems getting the shifter into (1-2), it could be a shift cable issue?

 

Like as in the valve body? Manual states 4th is controlled by the valve body. Does one solenoid controll all gear selections?