Oops ! Overfilled the rear diff !!

[Mellemel]

So I recently had a new diff cover welded on and the guy wasn't too sure how much oil to put in ! He thought he'd refilled it OK, but I began hearing a whining noise last few days from the rear, I checked the diff oil out of curiosity and to my surprise there was less than half a liter in ! There should be 2.75 in there according to the manual for the 3.4 with locker. I topped it up and dumped in approx the right amount, it was a bit hit and miss as I put in from a 5l can and emptied half in. Anyway, I see diff oil leaking out from where the U joint is ! Have I blown the seals ? Will the excess oil stop coming out or ????

 

[I_bRAD]

Is it even possible to put too much fluid in? It's full when it starts to leak out the fill hole! Hard to fill past that unless your truck was standing on it's nose.

My bet is the seals were gone anyhow, and that's why you only had a tiny amount of oil in it!

 

[gamefreakgc]

You're technically supposed to fill it about 1/4 in. below the fill line but not sure how much that matters.

If you filled it and went down, yeah it's leaking. I'd check your axle seals by looking behind the drum brakes as well, that's the most common place to leak.

The problem might be your differential breather is clogged and blown a seal. Make sure you take it off and clean it real good or replace it.

 

[Konkordmusk]

If you see diff oil from behind the u joint, then your pinion seal is bad and that's not the most fun repair ever.
Its really hard to overfill the diff. The front of the truck would have to be facing downill.
I agree with gamefreak that the diff breather may be clogged.

Lastly, why did you have a new diff cover welded on by someone who doesn't know how to properly refill a differential?

 

[Mellemel]

All valid points raised here, OK, the guy that welded the new cover only did that, the guys hoist he borrowed did the refill. This guy (a friend of a friend ) also fitted on a new longer breather hose, all about 6 weeks ago. The fill hole on the new cover, which is an after market one, is higher up than the original is. If I filled to spill out then the level of oil would be higher than the axle ! I don't think it needs to be that high ! From what I can tell the level of oil I put in is about a cm from the top of the axle level. And the vehicle was on flat ground !! There's no oil from the breather hose, just from the pinion seal, is that was it is ? So have I blown it ? I do have 375000 km on those seals !

 

[nevada]

All valid points raised here, OK, the guy that welded the new cover only did that, the guys hoist he borrowed did the refill. This guy (a friend of a friend ) also fitted on a new longer breather hose, all about 6 weeks ago. The fill hole on the new cover, which is an after market one, is higher up than the original is. If I filled to spill out then the level of oil would be higher than the axle ! I don't think it needs to be that high ! From what I can tell the level of oil I put in is about a cm from the top of the axle level. And the vehicle was on flat ground !! There's no oil from the breather hose, just from the pinion seal, is that was it is ? So have I blown it ? I do have 375000 km on those seals !

if its leaking, it needs changed. however, its unlikely that anything you did caused it. other than driving it that is.


they aren't terribly difficult to change. if you're unsure of it, its probably worth paying a shop the $50 or so to have it done.

 

[Konkordmusk]

if its leaking, it needs changed. however, its unlikely that anything you did caused it. other than driving it that is.


they aren't terribly difficult to change. if you're unsure of it, its probably worth paying a shop the $50 or so to have it done.

Pinion bearing preload is key here. They definitely are relatively simple to.change but it'll be important to note the preload on the bearings before, and to match it after installing the new seal AND the new pinion nut. This job should not be done without a new pinion nut.

Again, why specifically did you have a new diff cover welded on?

 

[Mellemel]

Again, why specifically did you have a new diff cover welded on?

Because after 18 years it had rusted thru and was leaking badly !

 

[csp]

It's not really a cover, it's part of the housing. A cover is what you find on an axle that can be unbolted from the housing as the way to access the ring/pinion/carrier/internals.

 

[jeremyc74]

Pinion seal sounds like the culprit to me too. Given the fact that this diff was already in bad shape, I think I'd just scrap it and get another one from a salvage yard.