Hi
I have a 2wd 96 xj sport and I daily drive it. It only has about 115,000 miles and it doesn’t get on the trails or get driven hard. About once every other month, while I’m on the highway going 60ish, the transmission just starts revving freely like it slipped into neutral. It doesn’t happen every time I drive on the highway, but it happens enough to be concerned about it. Everywhere I’ve looked has said something different. It ranges from something as simple as adjusting the tv cable or replacing a connector to needing a new torque converter or even a new transmission. I don’t know what to really try.
thanks

 

Don't fork out a new trans yet


When was the last time the ATF was changed?
Have you checked the level?
Adjusting the TV cable is always good measure.
You can have a look into the solenoids as well, measure them for resistance being within spec


I'm not well versed in trans problems but these things are the basics and free stuff. Others will chime in.

 

agree with above

check ATF correctly, warmed and in neutral, note color and odor

should be changed every 3 yrs or 30k miles. Use Dex 3

mark the TX cable with whiteout, lube the area with WD40, adjust as per FSM

Other tests such as time lag and stall test are detailed in FSM, free download

Once you have determined there is actually a problem (or not), you can then take it to a good trans shop to be rebuilt, confident you are not getting shafted for an unneeded rebuild
(if that is what is needed, hopefully not, and its minor, I replaced with a used one)

 

How is the fluid level and condition?

 

Fluid level and color is fine, just thinking about what else it could be

 

Have you adjusted the TV cable?

Have you ever changed the fluid?

 

Seems like we're all suggesting the same things, Cruiser..

 

Yup. Maybe they're falling on deaf ears?

Not everyone has learned that part of the diagnosis process is making sure what the problem ISN'T.

 

No I gotcha, the fluid level, color, and smell is fine. I just adjusted the tv cable and haven’t had a chance to drive on the highway yet. I still want to test the resistance ohms of the shift solenoids for peace of mind, I just don’t know what the best way is to test them, if I have to take off the trans pan or if I could test it from the tcm

 

Yeah funny you mention that- I hear myself explaining that to people on an almost daily basis..

 

Just here to learn

 

We all are!

(my comment was more related to life in the physical world)

 

Completely forgot about this thread since the problem stopped for a while. It started coming back lately in the summer heat and on the highway primarily. I would drive about 60-65 on the highway, cruising, and the torque converter would unlock and sometimes would shift out of overdrive (4th gear) as well. I would pull over or pull off the highway and came to a complete stop to shift back through all the gears and they would shift like normal. No CEL, don’t have any symptoms pointing me to the nss (like needing to start the car in neutral on having to wiggle the shifter), fluid level and color is good, tv cable adjusted multiple times, no bad idle, doesn’t overheat, shifts great on main roads just not on highways. I’ve backprobed the tps to test it and it is smooth increasing numbers up and down from no throttle to wide open throttle. I’ve unplugged the tcm and driven with it unplugged and shifted through all gears 1-4 and it shifted great up and down. I tested the tcm pinouts while I had the tcm unplugged and every single pin was within spec for solenoids, brake switch sensor, tps, etc. I’ve also cleaned all transmission connectors with electrical connector cleaner. My next thing to do is test resistances through the transmission connector on the firewall but I don’t know which one it is since there’s 4 bunched up around the trans dip stick.

 

You need to download the FSM as that tells you what color the wires are.

You cant do the test without that info

Also, you can unplug the TCM completely and drive it with the stick.

This will virtually eliminate TCM issues, although you will not have OD without the TCM plugged in

My best guess is you have either a problem with the Torque Convertor, it may be some other issue though

There are tests in the PCM for "engagement time" and a "stall test", which will indicate if its the TC

 

Yeah I found an online fsm and used the tcu pinout chart from that. I looked in other forums to find the pinout specs that I didn’t find in the fsm to test.

I’ll do the stall test when I get a chance tomorrow. What’s the engagement time test? I couldn’t find it in the fsm and I’ve never really troubleshot a transmission before but there’s not a delay shifting from P to R or R to D. The shifting from P to D or R to D is kinda harsh though.