Jeep TJ Wrangler front diff gearlube burn Any Jeep towers present?

[CARVAL Motorsports]

OK, completely puzzled here. We tow our '03 behind our motorhome, have done so for short trips and a long one to the coast from Ohio... never a problem. We returned last week from Mid Ohio racetrack, 1.5 hours at variable expressway speeds up to maybe 70 downhill a few times. Get home, and the putrid smell of burnt gearlube is present, mostly from inside. I check the status of transfer case, it is in neutral, I look underneath, then touch front diff and it is really hot. What happened here that has not happened before? I had the gearlube replaced, old oil smelled like burnt popcorn (!) no apparent damage to R/P, thats good (it was slightly overfilled by the way, so was the rear and the rear diff was not hot BTW), but I do not want to repeat this action. Everything else seems to be operationally correct as i have been driving it daily since.
When I tow, I place transfer in Neutral and gearshift in Neutral, and of course, deadkey is turned to first click to free up steering lock. Any chance the transfer case did not come completely to neutral, something dragging ???

[Doug Sage]

I don't know the answer but will be watching to see what others say.

[Roadking]

Carval: I towed a 99 TJ with auto tranny for 8 years and never had a problem. The Transfer case should be in neutral and the auto tranny is in park. The tranny is in park because The rear bearing on the tranny does not get proper lubrication if the engine is not running, hence, the auto is to be in park so as to prevent the output shaft from spinning. Check your manual.

I'm not sure on the newer manual 5 speeds, but in my older T5 5-speed in my CJ, and my 5 speed Peugout tranny in my TJ, I towed with transfer case in neutral and tranny in OD so as to keep the transmission output shaft from spinning, and also prevent engine from over-reving should the tranny spin for any reason.

It would be normal for both the front and rear diffs to be warm while towing as the gears are moving, bearings are spinning, and gear oil is being moved... and all of these create heat. Temps of 140 degrees or even as high as 170 degrees F would not be uncommon nor would be anything to worry about. IF the temps are pushing 200 degrees.. or hot enough to smell the gear oil... then something is wrong.

[Cruzer]

Can't figure that one out. On my TJ I did the same as you and never had any issues. If your transfer case wasn't fully in neutral you would be in one of the 4WD modes, which are next to neutral on the xfer case lever. If that was the case you would be locked to the transmission, which should be in a high gear. That would cause the wheels to drag and you'd know it. By running the manual tranny in neutral you could spin the back half of the tranny but not the engine, hence no drag on the wheels.

But if that was the case it shouldn't be any more different than driving down the highway in 4WD high mode and your diffs shouldn't have gotten that kind of heat. I guess if you maybe had a serious difference in tire diameter between the front and rear axles that could place more stress on one of the differentials but that's gotta be stretching it.

Things happen, which is why I always run 75W-140 synthetic lube in my differentials rather than 80W-90 dino lube.

[jackrobinryan]

Can't offer suggestion/solution here but can offer a pointer to what has been a very helpful site to me when I had problems w/ our Liberty.

www.jeepforums.com

Register for free and take a look at the forums for your model/year. Might be some discussion already there or you can post the question.

safe travels
jack

[CARVAL Motorsports]

Thanks everyone. I am a member at jeepforum also, and did post there too. Nobody can really figure this one out. One mentioned possibly a bad wheel bearing dragging or CV, but, I think I would feel that in subsequent daily driving. We have a short trip lined up in a couple of weeks, no interstates, but highway driving for about an hour, I will just monitor it closer, stopping and checking along the way.
Cruzer, I like your thought on the 75W-140 synthetic lube. May just change to that before any long haul.

Grazie!

[TAZ]

You may have had a bad bearing or cv and not known it. On my old F350 I noticed a noise now and then when breaking. Finally I assumed it was the brake pad indicators dragging and when I jacked it up I could sable the right front tire a good three inches. When I pulled the hub it was a a mess and I had no idea how I didn't notice.