Had the same issue with my 98 ended up being my shift solenoids. I got this link from Radi http://www.rostratransmission.com/tr...ansmission.php Use their web site to find a dealer. I bought Rostra solenoids which are name brand and American made for cheaper than e-bay or rockauto.

 

Let me clarify, I disconnected negative terminal from battery, performed resistance checks, conncected negative terminal and performed voltage tests. I'm saying maybe I had the CEL because the harness was disconnected from the TCM when I applied power to do the voltage checks.

 

Cool thanks! I will look into that.

 

Not good. I had the exact same problem on my 89 xj. Never did figure it out. Sold it and bought the grand Cherokee.

 

I've got an issue going on now that could be related to the original problem.

Today I've noticed a strange noise coming from the vicinity of the rear of the torque converter and the front of the transmission, sort of a rhythmic humming/whinning(wum wum wum wum) that increases and decreases with throttle. It does this in Park and while driving.

Also something new that's happened today that seemed unusual. Everyday I make a morning trip and evening trip to and from my house to my parents house to drop my dogs off, about 15 miles round trip with an average speed of about 45-60mph. I drive a company van and this is about all I drive the xj throughout the week. Usually with outdoor temps around 35 or less, my tranny temp will never get higher than 125, keeping in mind that I have an aux tranny cooler and temp gauge that I installed this summer so I'm not familiar with the average temp ranges of my xj. It will usually hang around 100-110 even though the engine temp is at 195ish.

Today the outdoor temp is in the teens with the wind chill in the single digits. On the usual daily trip this morning my trans temp averaged about 150 and peaked at one point at 180. This evening trip is when I noticed the hum/whine coming from under the xj, my trans temp stayed at 100 until I got to town and slowed down from 60mph to 45mph, at this point my trans temp suddenly shot up to 160. I realize I slowed down which should bring the trans temp up, but why wasn't I seeing temps this high when it was 30 degrees warmer outside? Could my trans fluid pump be going bad, hince the hum/whine noise? And btw, that noise was gone when I got to my parents and the fluids were all at operating temp.

 

Odd...

My owner's manual states that the normal operting temp is 170*F, but doesn't state at what OAT this would be.

You may want to do a cold fluid level check tomorrow morning after the trans cold soaks over night. See below.

This check may reveal a bad TC or trans oil pump if the fluid level does not drop to the level stated below.



Other than this, the only thing I could suggest is setting the parking brake, putting the trans in drive, depress the brake pedal while depressing the gas pedal, loading the torque converter and making the trans torque. See if the noise is there or not.

Loose torque converter to flex plate bolts my be loose but they usually make a clunking/knocking sound.

 

Thanks, I will do that check in the morning. It just seems that even with cold outdoor temps I should have been seeing higher trans temps regardless of the aux cooler. Also for added info my trans temp sender is located in the discharge side if the trans not the return(cooled) temp.

 

Just left parents house. Let xj warm up because its freakin cold out, temp was at 195ish. The hum/whine was present, I loaded the TC as Ken advised and it made no change to the noise. BUT...less than a mile from my house my Check Engine light came on. Will have to wait until tomorrow to see what that's all about, hopefully it will give me a clue on this problem!

 

Did you do the cold fluid level check?

 

I was running late this morning and didn't have time. It's been sitting for about 7 hours now in single digit temps, I will do it when I get home then im taking it to get the diagnostic ran for the Check Engine light. Will post up my results later tonight. Thanks!

 

Okay, I did the cold fluid check. My cold fluid level with engine off is above the full line and just below where the dipstick starts to bend/wave. So its high compared to the picture. Upon stating the engine and immediately checking the level there was no change in fluid level, but I immediately wiped the dipstick clean and rechecked the level and it was a little lower. I continued to recheck and in no more than two minutes the level dropped roughly the same level that's between Full and Add. It is 6 degrees out while doing this test, so I'm thinking it would be logical to assume cold fluid viscosity could be slowing the dropping rate of fluid on the dipstick.

As for the CEL codes:

P0700 - generic TCM fault signal to PCM

P1698 - No CCD messages received from the TCM. Possible causes; bad TCM or short to ground or power. Reported fixes seem to be anything from bad grounds, solenoids, shorts or TCM replacement.

P1898- No definition available. Reported fixes seem to be solenoid #1 replacement, valve body replacement, TCC solenoid replacement.

*All above OBD2 code definitions are from O'Reillys.*

After reading other posts it seems like I have a couple odd/pain in the butt codes... I'm still leaning towards solenoid replacement(all 3) but I'm not certain enough to spend nearly $500 on it.

 

That fluid level should have dropped immediately to near the bottom of the dipstick, regardless of the outside air temp. There's an issue there. TC or pump.

That is a chunk of codes there.

 

I would lean towards the pump due to the erratic tranny temps. If its not pumping fluid I could see the fluid in the cooler line staying cold then when it starts pumping the temp goes up. The temp reached 190 on my way to get codes scanned. But I'm not sure about anything... Seems like if the pump was bad I would have burnt up the tranny by now.

 

Have you checked your fluid level with the trans fluid up to operating temp (+170*F)? If it's overserviced the fluid may foam.

Bad clutch discs in the TC can cause the fluid temp to rise.

Low fluid pressure/flow in the trans may be causing all the DTC's (?)

 

Yeah I checked it yesterday. It was just a little above the full line. Do you think having it slightly overfilled could be causing me some issues? And no I've never seen any foaming of the trans fluid.