Hey, this is my daily driver so need help fast.. I have another truck in Pittsburgh but im out in Philly attending school.. I was driving home from work today and everytime I let go of the gas my whole truck will shake and you can hear a very bassy 'Humm', and it smelled like grease real bad when I opened my door. So I look under my truck and it looks like the oil and grease from my diff just exploded, there is oil everywhere (tires, brakes, gas tank, bottom of bed, etc.) So my question is do I need a new diff or just a seal? And how hard is it to replace? I had plans to go to a junkyard tomorrow for some sensors should I pick up a diff from a junkyard?

Thanks very Much.,..
Mario

 

That sounds like your breather was stuck closed and the pressure built up. I don't know if the pinion seal is toasted, but the least you will have to do is fix the breather and refill the differential with fresh oil (and clean the old oil up).

 

Is your diff breather plugged ?

Mike in AR

 

I would imagine that the diff breather was rusted shut like mine were. When I took the rear one off to do the breather extension, you could hear the pressure equalize.

 

My breather is good, I cleaned it out last summer, and just checked it, it worked good.. It just looks like my seal just Went for a joy ride!!! how hard is it to replace this? Can I do it in my apartment parking lot?

Thanks,
Mario

 

Where is it leaking from - the pinion (where the driveshaft connects to the thirdmember) or the gasket where the thirdmember attached to the axle?

In either case, you have to drop the third member which is not all that tough. You will need to be able to jack the truck up and put jackstands under the frame so the suspension is in droop. Then you need to take off the wheels, disconnect the brakes, undo the 4 bolts on the back and pull the axles. Then undo the 4 bolts on the driveshaft. Support the thirdmember with the jack while you undo the ABS sensor and the 10 bolts that attach the third to the axle.

If it's just the gasket, scrape off the old one and put on the new one and put it back together.

If it's the pinion seal, you'll have to take the insides of the diff apart to get the pinion out. MAKE SURE YOU WRITE DOWN HOW EVERYTHING GOES. The alignment of the pinion on the ring gear is critical. Honestly, if it's the pinion seal, I would take the third member to a shop and have it repaired professionally.

 

Mario---With the tranny in neutral, shake the rear driveshaft and see if you can see any massive pinion movement. ZUK

 

hey tc, why do you have to go thru all that for the pinion seal?

Can't you just pull the pinion nut, and flange, then pop the seal out? The pinion will be centered when u put the flange back on. I notched the pinion nut and thats how i knew how hard to tighten it back up. A mechanic friend of mine told me to do it this way. Is this wrong? It dosen't make noise or leak after i fixed it. Why do u have to drop the third member?

 

maybe he is suggesting you do it that way to make sure there is not more damage inside that you wouldnt find out about by just replacing the seal. i replaced the seal the 'easy' way but it was just leaking a little bit and i didnt have a major melt down as mentioned above.

lee

 

Thanks guys.. You can tell it came from the front of the 3rd where the drive shaft connects to it. So I'm guessing its going to be the pinion seal, which I'm going to have to install the easy way (I know I might regret it but I need my truck). I'm going to call the dealer now and ask him if he has this part.. I just checked for play also, and there is alot.. So this tells me its the pinion seal correct?

Thanks,
Mario

 

good point leebee.

my vent was stuck shut due to mud, and it blew out the pinion seal. The thing that i kinda didn'nt understand was this: on a rear end without a third member, the pinion gear was pressed into the housing. So when u go to do a pinion seal the pinion gear would not move. But when i did my seal on the toy, the pinon gear was kinda loose. It seemed the flange and pinion nut held it in place? I do nt know if thats normal or not, but it's been a few months and it hasent blown up yet. lol

 

Mostly 'cuz I didn't know the easy way. :pat:

Good advice is to listen to Zuk before just about anyone else when it comes to gears...

 

Well Mario, the excess pinion play caused the seal to leak....so if you want to try the band-aid approach, you can replace the seal and try snugging the nut until the play 'disappears'. I understand others have had some good luck but it still means you are going to have to do a new crush sleeve...or preferably an upgraded solid collar sometime in the future. All you can do is delay the inevitable.

here's the pinion seal number 90311-38047

 

Here is Roger B write up on the changing the pinion seal:Write up

 

Alright, Thanks for all your help guys! I just got done putting the new seal in.. When I got the drive shaft off, the nut holding the flange on wasnt even snug (took it off with my fingers) You can also tell someone else was in there before the nut was all F-ed up, and the seal didnt look that bad? Since the nut wasnt on, i didnt know where to torque it to so I just took it past (where it was stacked) about a quarter of an inch...

Thanks agian.
Mario

 

I got an error when launching this link... :pat: :pat:

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try this

I copied 2x in the link location :pat:

 

i hope you used a pinion seal from napa or some reputable shop and not the oem as you'll probably be changing it again soon

 

ugh.. why would the oem seal not be any good?