Rear diff leaking

[Sean]

Looking to tap the infinite wisdom of the CSC.

I have a 1998 Isuzu Rodeo and the rear differential is leaking. It's leaking where the drive shaft goes in, in the front. It seems like it's a seal/gasket sort of thing that is broken/ripped (although I can't see it to confirm) and the diff oil is coming out of there. The fluid is all over the area where the drive shaft goes in from the spinning. The leak isn't very fast but if it sits for a few hours there is a tiny puddle under the vehicle.

Anyone have experience with this?
Does it sound like a seal that's worn/broken?
If it is that, is it something I should be able to fix myself?

Any insight would be great!
Thanks.

[usmcab35]

yea its more than likely your seal, its not to hard, just pop off the yoke and pop the old gasket out and get a new one in there, if you take it to a shop it shouldnt be to spendy, its a pretty common thing. if you do take it apart, just double check everything for cracks, wear, etc, that way you dont put junk back in it.

[salsashark]

A quick google mentioned something about a vent that could plug causing the leak.

Do you have an AAMCO anywhere close? They'll inspect it for free and quote the repair. There's one down the street from my house and they've always been very honest with me.

13 year old car... better get the Chiltons or Haynes.

[usmcab35]

yea that is possible too, its a little metal looking cap on the top, you may or may not be able to take it apart, not to sure with Isuzu axles, but you should be able to tell if there is crap in it that is plugging it.

[Sean]

Good info guys, thanks.

Yeah, there is an AAMCO near me. Maybe I'll have them take a quick look?

It's not the plug. I've opened that before to put more fluid in (no, I didn't overfill). Plus, judging by the spray pattern, it's coming from something that's rotating towards the front. I'm 99% sure it's some sort of seal between the diff and drive shaft. Just didn't know if I should be messing around with it? Seems easy, but you never know.

[TFOGGuys]

Good info guys, thanks.

Yeah, there is an AAMCO near me. Maybe I'll have them take a quick look?

It's not the plug. I've opened that before to put more fluid in (no, I didn't overfill). Plus, judging by the spray pattern, it's coming from something that's rotating towards the front. I'm 99% sure it's some sort of seal between the diff and drive shaft. Just didn't know if I should be messing around with it? Seems easy, but you never know.

It kind of depends on what type of bearing they use for the pinion gear. If the bearing preload is dependent on a crush sleeve like many US designed diffs, you may be biting off more than you want to try to change the seal. If they use a tapered bearing with a preload collar, then your biggest worry is finding an impact gun to get the yoke off so you can swap the seal. If this is the case, be sure to check the yoke for wear where the seal contacts it to ensure there are no grooves. If there are significant grooves, replace the yoke, as it will never seal properly. Again, a service manual is your friend.

Yes, I was a car mechanic in a former life....

[Rooster]

ninja'd

[Hibs]

Yep, pinion seal. Easily changed if you got yourself a 1/2 impact gun, rubber mallet and a "hook" seal puller.

** just make sure to torque it to the proper spec when putting the pinion nut back on. Most nuts have pre-installed lock-tight on them. I usually just buy a new pinion nut ever time. Since the crush sleeve inside the diff is all ready "crushed" you can get away with just zapping on a new nut after you change the seal. I've done it like this many times, no problem. The absolute "BEST" way to do it, take the whole diff apart, put in new crush sleeve, then new seal/nut then do the proper "crush and torque" but that's a PITA just to change a seal.

[Sean]

Damn, no impact gun. Guess it's off to the shop.

Thanks for the input.

[Wrider]

Damn, no impact gun. Guess it's off to the shop.

Thanks for the input.

I've got an impact gun you can borrow if you have a compressor to use it.

[Sean]

I've got an impact gun you can borrow if you have a compressor to use it.

Unfortunatly I don't. Thanks for offering!

[MetaLord 9]

13 year old car... better get the Chiltons or Haynes.

This.

Oh and Sean, I have an impact wrench and an air compressor if you need to stop by and use 'em

[Sean]

This.

Oh and Sean, I have an impact wrench and an air compressor if you need to stop by and use 'em

Yeah, I know I need a book, but I'm hoping to move it down the road before to long. Thanks for the offer. I'll let you know. I think I'm going to mess with it this weekend a little and see if I can't break some shit?

[krod]

It kind of depends on what type of bearing they use for the pinion gear. If the bearing preload is dependent on a crush sleeve like many US designed diffs, you may be biting off more than you want to try to change the seal. If they use a tapered bearing with a preload collar, then your biggest worry is finding an impact gun to get the yoke off so you can swap the seal. If this is the case, be sure to check the yoke for wear where the seal contacts it to ensure there are no grooves. If there are significant grooves, replace the yoke, as it will never seal properly. Again, a service manual is your friend.

Yes, I was a car mechanic in a former life....

Smart guy I suggest you listen to him. The crush sleeve is verry important sets the preload on the pinion bearing. When they come into the shop I put a new seal and cruch sleeve in every time. (yes I am a auto mechanic drive train and transmissions)

[Sean]

Smart guy I suggest you listen to him. The crush sleeve is verry important sets the preload on the pinion bearing. When they come into the shop I put a new seal and cruch sleeve in every time. (yes I am a auto mechanic drive train and transmissions)

I trusted him as soon as I read it. Jim's a trustworthy guy and has forgotten more about fixing shit than I will ever know.

I was planning on heading to a shop tomorrow. Thanks guys!