Binding noise from the rear (TJ '01)

Do you have the Trac-Loc rear differential? Crawl under the TJ and look for a small metal tag on the differential saying "limited slip additive required."

If so, it is a limited slip design with clutch packs that can sometimes bind slightly if the rear fluid has not been changed in a long time. Fluid should be changed every 30000 miles or so.

Most brands of differential fluid already contain the additive, but if not, you can buy a small bottle of the additive at most auto parts stores.

Tom

Do you have drum brakes in the back?? If so, they always have some residual pressure on them by design, you could have some valving going bad, or the shoes are sticking for some reason. Good luck with that.

TW: If you have the TRAC-LOC plate type limited slip diff, it sounds like "stiction" in the plates to me (will usually show up after a highway drive and up to full temperature, then upon making a turn under power). This is normally fixed by a fluid change, adding the recommended additive and driving some "figure 8's" to work the fluid in. It should be OK by then. This is providing the plates are mechanically sound. If not, further repairs could be required. Bob

I have Dana 44 and drum brakes in the back. Because of Dana 44, I have no ABS brakes (I am so glad).

Would it be possible for both sides in the back to develop sticking valves and shoes at the same time? I had never noticed this noise before this. Can I take the drums off and clean everything with brake clean or something? Would that help? I am trying to save money for suspension and tyre upgrade, so don't really want to go to the shop unless I really have to. Thanks for your help and suggestions.

Cheers, TW

I do have Trac-Loc limited slip differential. The noise was after highway drive for 90 minutes. I had come to a complete stop at a stop sign on the off ramp and heard it when I was making a left turn as I started moving at a slight incline. The second time as well I was making a turn, but this time it was a right turn. The sound seems to be coming from both back sides, therefore, I am assuming its the diff. because both drum brakes starting to stick at the same time in point would be very coincidental, then may be it was my lucky day (may be I should buy a Lotto ticket for tomorrow, jackpot this week is NZ$15.5 million!!!). I need to find an open auto store over the Easter break and buy the oil. Do you think it would be beneficial in the long run if I go with synthetic oil this time.

TW

Thanks for the reply. Yes, I do have Trac-Loc rear differential. I have

40,000 kms on the clock. I had asked the dealership for the need to change the differential oil at last service (37k) and the service manager said it should be done at 48k service for my driving style. At 37k service auto transmission was serviced. The TJ was under warranty till two weeks ago, now the service will be done by myself. Being Good Friday, everything is closed here now. I'll find an open auto parts store tomorrow and buy the differential oil and change both front and rear oils. Hopefully that is the problem. Do you think I will be better off going to synthetic variety? I do go off-road on the weekends, but its nothing hardcore as yet because the set-up is factory stock (not for long though).

I am still trying to source the Factory Service Manual for mine, being in New Zealand, its a right hand drive export model.

Have a nice long weekend, TW

Adding to my earlier post.

I have just read the owners manual (again) and it suggests under Schedule "B", diff oils should be changed at 38k kms. I guess I am at 40k so the oil is breaking down and needs replacing. I just wonder which schedule the dealer was following.

Am I better off with SAE 80W-90 API-GL5 grade oil in both front and rear (with additive for Trac-Lok in rear) or should I go for SAE 75W-140 API-GL5 grade oil (with additive for Trac-Lok in rear). The second one is mentioned in the owners manual for towing and heavy load applications. Would Shell Spinax HD fit this grading or do I find something in Mobil (like Mobil 1). I have been using Mobil lubes and Shell gas in all my vehicles. I guess off-roading in mud and soft can be classed as heavy load applications. Any opinions from the group would be appreciated.

Have a nice break everyone, TW

TW: From this and your other posts, it sounds as if "stiction" could be the problem. Good excuse to change the fluid in any event. I don't know what DC's recommendations are for the '01 but for the '03 Rubi they say to go to the 75-140 synthetic for heavy usage such as trailer pulling. The DC dealers up here (Canada - West Coast) carry it under the Chrysler - Jeep brand (Chryco I think). Their mentioning of trailer pulling and heavy usage tells me it will most likely have better hi-temp characteristics. With the

75 low end, it should flow better at low temps as well (don't know about the range needed in NZ though). Hope that helps, have a good holiday. Bob

TW; Given the choice (and considering the application ratings) I will always go with the synthetic option in an automotive application. Bob

Thanks Bob. I am leaning towards the 75-140 synthetic. Although temperature rarely (never) goes below zero in Auckland and max in summer is around 26/28C, I do a lot of highway driving some weeks of the year. One of our clients is about 125 kms away (round trip 250 kms). Dealer is closed today, I'll see if they are open tomorrow for some advice. I don't pull any trailers at all. Just some steep hills and highway speeds. We are heading towards winter.

I was just checking the

website and they recommend three Mobil 1 oils: Mobilube SHC 75W-90 / Mobilube SHC 80W-140 / Mobilube HD

75W-90 for a '01 Jeep Wrangler. I think I'll stick to Mobilube SHC 80W-140 and add the additive in the rear for LSD.

Hopefully this solves the issue before it becomes a big problem ($$$).

Thanks for all your help. TW

It is almost for sure your rear differential. I would change the fluid and be sure the additive is in it. Synthetic for your type of driving is not necessary, but you can use it if you want.

Tom

Thanks Tom. I'll change the oil this weekend as soon as I can find any auto shop open. Its against the law for shops to remain open on Good Friday and Easter Sunday in New Zealand..

If the price difference is not huge, I'll go with synthetic.

Cheers, TW