Rear Differential driping oil

[happyface]

Hey everyone, My 98TJ 4banger had regear to 4.88 couple years ago. Recently the rear differential is driping oil once I stop the jeep. If it driving I guess is OK. Do you think should I try to tight it up those bottom nut? Or it time to change the diff oil since I also install the factory limited-slip. I did not do the installation. I brought to the shop and have some pro did it for me. Please gave me some adviced. Thanks :confused: :confused:

[HotRod YJ]

Check the pinion seal, they are bad to leak and may need to be replaced. It's very rare that the cover will leak unless you drug it over some rocks and peeled it up. If the pinion seal is leaking, it will run down the housing and drip off the very bottom.

[Tonka]

Not being a mechanic, I can speculate that if is leaking parked, it most likely is leaking when moving, especially if the oil is getting sloshed around. I would try tightening the bolts a little more (do not over tighten). If that doesn't work take it back if the work is under warranty. If it is not under any warranty, I would open it up and change the oil and gasket (if something can get out, something might have got in). 4X4XPLOR maintenance page (http://4x4xplor.com/mods-TJ.html#maintenance). Eddie from that site is a great source of information if you have questions.

I have heard that there are reuseable gaskets, but I do not know of their reliability. They are a bit of ching-ching but might be worth using rather than trying to clean the old squeeze ones off.

[trainbrainmike]

[QUOTE]Originally posted by HotRod YJ:
Check the pinion seal, they are bad to leak and may need to be replaced. It's very rare that the cover will leak unless you drug it over some rocks and peeled it up. If the pinion seal is leaking, it will run down the housing and drip off the very bottom. [/QUOTE

Pinion seal is where the universal joint at the rear of the drive shaft goes into the front of the differential. (Not trying to be a smart arse, just want to be sure we are all talking about the same thing.)

Yep, this is likely the problem. Remember, if you ever take a leaking diff under water, and it cools, it will suck water in the same place the lube leaks out, but faster,'cause the water is "thinner" than the lube. If there is any appearance of "chocolate milk" to the lube when it is changed, the water has already been there....HTH smile.gif

[happyface]

The warranty is out for a couple of years. As I remember I don't think I have hit anything over the differential. I never open a differential before. I did my suspension myself. I have some mechanic skill. Do you think I can able to handle it?

[RednexInc]

resealing the rear cover is easy pull the cover off and clean with putty knife and some brake cleaner to remove any oil and get some gasket maker at the auto parts store apply to the cover and put it back on fill with oil and some friction modifier and enjoy

but.. if its the pin oin seal you got little bigger job on your hand pull the the rear section of the drive line remve the yoke and remove the seal use a small heel bar to pop the sael out put a new sael and reassemble and enjoy

[HotRod YJ]

Originally posted by RednexInc:
but.. if its the pin oin seal you got little bigger job on your hand pull the the rear section of the drive line remve the yoke and remove the seal use a small heel bar to pop the sael out put a new sael and reassemble and enjoy Not quite that simple if you want to do it right and have the rear survive for another couple of years. The pinion nut is torqued for a set amount of preload on the pinion bearings. You can't just tighten it back down. The best way I've found to do it is to clean the end of the pinion stub and the nut first so you can mark theend of the stub and the nut. This way when you reinstall and tighten, you have a mark to tighten back down too. You need to get the nut back to EXACTLY where it was when you took it off, so realign the marks exactly.

There isn't a set "torque" number that you can use a torque wrench either. If done properly, the nut is tightened until the bearings are loaded enough to require a set amount of drag
to turn the pinion. Too tight and you'll burn up the bearings, too loose and they won't stay together either. It's still an easy job, just take the time to mark your starting point and that gives you a place to go back to so you know for sure it's back the same as it was. I used paint pin or in a pinch, I have used a chisel and a hammer to make a match mark accross the stub and one side of the nut.

[Tonka]

Originally posted by happyface:
I never open a differential before. I did my suspension myself. I have some mechanic skill. Do you think I can able to handle it? The most invlved project I have done is a 2" BB (initially, I was taking on a challenge). I am not a mechanic (nor have the aptitude) and I was able to change the differential fluid rather easily in my D30 and 35. The old gasket can be like very strong glue. Just pry the plate off, catch the oil, scrape off the old gasket(p.i.a.), clean the inside with brake fluid, squeeze a new gasket on, reassemble and filler' up.

[Knuckelhead]

Originally posted by HotRod YJ:
The pinion nut is torqued for a set amount of preload on the pinion bearings. You can't just tighten it back down. The best way I've found to do it is to clean the end of the pinion stub and the nut first so you can mark theend of the stub and the nut. This way when you reinstall and tighten, you have a mark to tighten back down too. You need to get the nut back to EXACTLY where it was when you took it off, so realign the marks exactly.

There isn't a set "torque" number that you can use a torque wrench either. If done properly, the nut is tightened until the bearings are loaded enough to require a set amount of drag
to turn the pinion. Too tight and you'll burn up the bearings, too loose and they won't stay together either. It's still an easy job, just take the time to mark your starting point and that gives you a place to go back to so you know for sure it's back the same as it was. I used paint pin or in a pinch, I have used a chisel and a hammer to make a match mark accross the stub and one side of the nut. [/QB]Exactly! I like it when someone gives sound advice with a reason for it. ;)

[happyface]

Sound easy. I have change differential oil on my suzuki samurial before. I will try to open it up next week to see what going on. Thanks for your advice.

[disturbed 1]

Do a search on pinion seal replacement here. Lots of info....read it all and form your own opinion on how to change it out. Different people do it different ways with the same result.

[disturbed 1]

Knucklehead-I see you've become quite the post *****! Congrats on cresting 3000. tongue.gif :D

[Knuckelhead]

I'm learning a lot by asking questions and passing on what I learn. They count those posts? :D

[happyface]

Thanks. I will. smile.gif