transmission problem i think

Ok its a 90 4.0l auto np231.
It starts fine and idles fine. Once in reverse it feel like it might die.
From 1st to 2nd its fine. The constant hesitation till it shift. Then it is good till I have to continue to accelerate then it will hesitate till in final gear. But it cruises fine from 65 on.

Now if I floor it and keep it floored the hesitation is gone and the trans seems to shift smoothly or at least a lot better.

I have done searches.

So far going from other peoples issues I have gathered I should check

Tps
Crank postion sensor
Cam position sensor.

But never the transmission.

So anything else?

If your fluid is nice and red and at proper levels...and nothing leaks or clunks or slips, then the tranny itself should be OK.

Check this link...

http://www.greatlakesxj.com/tech/TPS.html

Cam or Crank sensors, I doubt it, IMHO. If it were either of these you'd have spark and idle trouble all the time.

If it's not TPS related it sounds more like a fuel delivery problem. Check your fuel pressure with a gauge (to be bought or rented from your local AutoZone or Kragen type store) on the schrader valve from idle through WOT and see what you come up with.

Ok, I'll ask why.

Why wouldn't you check the aw4 fluid level?

Why wouldn't you clean, lubricate with dielectric grease, and properly adjust the NSS?

Why wouldn't you adjust the shifting cable?

Why wouldn't you adjust the throtle body to trans cable (kickdown cable?).

Just curious, as my 90 is manual. Oh yeah, I have read here on other posts that the NSS doesn't effect shifting, so I'm also a little curious why the writers at JP Magazine say it does.

The TPS could be the problem.

My only answer is haven't had time. Just got the jeep. Looking for ideas thanks

Obviously fluid level. Next, check TPS with voltmeter. If you need more on the TPS, just ask.

jeepnleo said:

Ok its a 90 4.0l auto np231.
It starts fine and idles fine. Once in reverse it feel like it might die.
From 1st to 2nd its fine. The constant hesitation till it shift. Then it is good till I have to continue to accelerate then it will hesitate till in final gear. But it cruises fine from 65 on.

Now if I floor it and keep it floored the hesitation is gone and the trans seems to shift smoothly or at least a lot better.

I have done searches.

So far going from other peoples issues I have gathered I should check

Tps
Crank postion sensor
Cam position sensor.

But never the transmission.

So anything else?

Click to expand...

TPS
Most all grounds
Most all connectors
EGR, motor tends to stall at low RPM's, runs fine at higher RPM's when stuck open, when stuck closed you'd likely never notice anything.
O2 sensor, the tip off here is when you floor it, the ECU uses a standard fuel curve and many of the other sensors are dropped from the loop.
Checking the TV cable adjustment is never a bad idea.
Cam position sensor would likely be last on my list, most any other sensor before this one. In most circumstances it really doesn't do much in the Renix motor. Though it is fairly easy to test. Exception is if it has a short, it will cause all sorts of grief.

joe_peters said:

Ok, I'll ask why.

Why wouldn't you check the aw4 fluid level?

Why wouldn't you clean, lubricate with dielectric grease, and properly adjust the NSS?

Why wouldn't you adjust the shifting cable?

Why wouldn't you adjust the throtle body to trans cable (kickdown cable?).

Just curious, as my 90 is manual. Oh yeah, I have read here on other posts that the NSS doesn't effect shifting, so I'm also a little curious why the writers at JP Magazine say it does.

The TPS could be the problem.

Click to expand...

The neutral safety may complete a circuit in the Renix era XJ's, but the TCU is mostly autonomous and fairly dumb. The only feedback I can remember the TCU getting from the NSS, is whether the shifter is in drive or 1-2.

Ok so I only had a chance to check fluid levels.
When checking cold it looks to be overfilled. When checking hot it looks to be about right if not a little over.

Can a fluid level that is to high cause this problem?

Also the fluid color looks red with a little bit of a brown look once wiped off and it dries on white cloth.

It smells like gun cleaner.

Any input???

Red is good, overfull is not (as a rule).

If the fluid is burnt it will appear more brownish and will smell very different from new fluid. Never did a dry test on white cloth.

I clean lots of different firearms and use different chemicals for different situations, so I can't comment on that.

Check and adjust those things that set mechanical limits first. Then check and adjust the things that are electrical in nature.

Try and follow a logical path. Diagnostics requires a broad view, but you must work to eliminate variables. While checking and adjusting the shift linkage is not glamorous, it costs nothing but your time and should be done for no other reason than you don't know if it is set correctly right now. Then move to the NSS, clean, lubricate with dielectric grease and adjust it, that only costs you the dielectric grease. Setting the throttle body cable is quick and easy, cost nothing. Keep on checking/testing/cleaning/adjusting and you will narrow it down.

Good Luck.

I nned a chiltons or a good flow diagrams

Have you tried pulling the negative battery cable for a few minutes? Mine was running like crap, someone suggest resetting the ECM by removing the cable. It worked.

No haven't tried that

ok so i checked cold levels and they are to high. i checked hot levels and its about 1/2 inch to high.
oh and in sunlight the red isnt so red more brown. so i hope a fluid change will solve it. and i will replace filter and gasket.

jeepnleo said:

ok so i checked cold levels and they are to high. i checked hot levels and its about 1/2 inch to high.
oh and in sunlight the red isnt so red more brown. so i hope a fluid change will solve it. and i will replace filter and gasket.

Click to expand...

These are all good ideas to do for your tranny but may not fix your problem as it sounds more like the motor having issues. My bet is a TPS just outa experience with about 4 Renix's. You can test them but it's difficult to tell if there o.k. I had one that only had problems after about 40 minutes of driving and the TPS "tested" fine.
The TPS affects both your tranny and your motor.
Just my 2 cents.

I will check the tps everyone is telling me to. I hope after fluid and filter change and hopefully adjusting the tps it will fix the issue.

Ok so I checked tps noticed to bad wires and It didn't measure correctly. So I replaced it. When I went to check voltage on new one it was also way off. So I went for test drive and everything runs great now and the xj shifts great now. So I guess ethier my multimeter is bad or I am not measuring correctly.

I still on changing out fluid and filter since it is dirty and over filled.

Do I need to measure voltage on new tps if xj runs fine now. Or should it be good.
Hopefully if I do need to check I can find a local member that can help me out.