Front differential leak

[Frankd1]

2003, Envoy SLE, 74,800 miles:

I noticed a drop of diff fluid on the garage floor, under the front diff.

I drove the truck up on ramps to have a look and sure enough, the area around the seal where the drivers side CV shaft/axle plugs in, is damp. The inside edge of the inner tripot is also damp. I noticed a droplet that was formed on the lowest point of the diff case as well as directly under the drain bolt. I'm guessing that fluid seeps out from the seal and runs down along the outside of the differential case and forms a droplet at the lowest point of the case then drips from there.

I sprayed the entire area down with brake cleaner and dried everything. I did this yesterday but I haven't noticed a drop on the floor yet, only a matter of time I'm sure..

Do these diff seals commonly leak? Do they generally just slowly seep or, do they completely give out resulting in a major leak? This would be my main concern until I can get to replacing the seal....

I also had a look at the back side of the diff where the pinion seal is, and it looked a little damp under the black plastic cover that is directly in front of the yoke (the plastic piece that turns with the propeller shaft) - I'm guessing that this plastic cover is just a dust shield of sorts....

I cant tell if the pinion seal is leaking as well or, if its just fluid that has run back along the differential case over time..

 

[CaptainXL]

Do these diff seals commonly leak? Do they generally just slowly seep or, do they completely give out resulting in a major leak? This would be my main concern until I can get to replacing the seal....

Hi Frank. Welcome to GMT nation. My main concern would be checking the front diff fluid level and condition before replacing the seal. If it's a slow leak then toping it off might be fine so long as the drips per time interval don't increase and there is no metal in the oil.

50,000 miles is a good time to change the transfer case, transmission and front+rear axle fluids. In extreme conditions of high heat, cold or towing then 30,000 miles is a good idea.

I have 135,000 miles on my Envoy and changed the rear diff fluid at 110,000. I tow during the summer. And at my current mileage the differential fluid was very dark and the cover magnet had a respectable amount of fine powder metal on it.

 

[Frankd1]

Thanks CaptainXL!

I did in fact change all of the fluids myself - transfer case was done at 43,000miles, the transmission, front diff and rear diff were all done at 63,000miles. In all cases the fluid coming out looked good, didn't smell burnt and there was very little metal powder if any at all on the magnets. The truck currently has just under 75,000miles on it

I have been checking the level of fluid in the front diff and it has not changed or gone down since doing the drain and fill last March (2012).

I was just wondering if these seals are a common problem and if there is a risk that they go from a slow seepage to a major leak because they blow out...

Thanks again.

 

[CaptainXL]

I was just wondering if these seals are a common problem and if there is a risk that they go from a slow seepage to a major leak because they blow out...

Thanks again.

Oh I got ya. That I do not know for sure. But from my experience there has been little talk around the forums about pre-100k seal leaks (aside from axle seal leaks)....if that is any consolation to you. Maybe do a few searches and see what you come up with.

 

[bfairweath]

Yes, that seal fails frequently. There are a number of DIYs out there. I did mine a couple months ago. The leak will get progressively worse until you change it. The seal is a dealer only item. Costs about $15.

 

[Frankd1]

Ok thanks! That it is next on my list, I just did a coolant system flush, replaced the thermostat, coolant sensor, and upper and lower rad hoses yesterday so I will start planning to change that seal out..

 

[xtitan1]

Does axle fluid and differential fluid and transfer case fluid all mean the same thing? (Obviously a noob here)

 

[CaptainXL]

Does axle fluid and differential fluid and transfer case fluid all mean the same thing? (Obviously a noob here)

No, not the same...

Axle fluid = same as differential fluid - Synthetic 75W-90

Transfer case fluid = GM Auto Trak II or Royal Purple Synchromax

 

[RedEnvoyDenali]

Yes, that seal fails frequently. There are a number of DIYs out there. I did mine a couple months ago. The leak will get progressively worse until you change it. The seal is a dealer only item. Costs about $15.

This is the cheapest and easiest seal to change. Mine started leaking just 1 week before a 5000 mile trip. Didn't have time to change it and didn't want to put this many miles on with a leaking seal, therefore took it to my favorite shop when I don't want to do the work myself. They had it changed in about an hour and the charge was not exorbitant. Still because I work so cheap much more than doing it myself

 

[CaptainXL]

Gerry, I can think of at least 4 other seals that would be cheaper to fix. That would be the seals on both ends of the front and rear driveshaft.

 

[bfairweath]

I used this post from offroadtb to do mine. Seemed to be the most straightforward one out there. You have to keep the end of the CV shaft completely parallel to the seal face to get it to clear (both removing the CV shaft and reinstalling).

offroadTB.com - View topic - Front Differential leaking

P.S. I had the same seal puller from Harbor Freight. It also broke while trying to remove the seal.

 

[xtitan1]

I used this post from offroadtb to do mine. Seemed to be the most straightforward one out there. You have to keep the end of the CV shaft completely parallel to the seal face to get it to clear (both removing the CV shaft and reinstalling).

offroadTB.com - View topic - Front Differential leaking

P.S. I had the same seal puller from Harbor Freight. It also broke while trying to remove the seal.

Something from harbor freight broke!?!??

 

[bfairweath]

Yeah, I know. At least they give you your money back.

 

[xtitan1]

Yeah, I know. At least they give you your money back.

Oh I was just making fun of harbor freight, not you. I buy stuff there too. For some things it's actually a smart way to go. For others, not so much.

 

[RedEnvoyDenali]

Gerry, I can think of at least 4 other seals that would be cheaper to fix. That would be the seals on both ends of the front and rear driveshaft.

Perhaps I misspoke. Not nearly as much fun as the passengers side of the front differential.

 

[Frankd1]

Thanks! I will check out some of the DIY threads online.

Looks like Harbor Freight has a 10 piece bearing race and seal driver set currently for $29.99. Is this set what you guys are using for this job?
If thats the case, I will pick one up when I am in Michigan for Thanksgiving in a few weeks...

 

[bfairweath]

I can tell you don't buy the cheaper seal driver kit that HF has (it's about $15). POS.

 

[Frankd1]

Ok, thanks, I have seen the cheaper one...

 

[waz3377]

I noticed a leak that ran down onto my front differential case. It is orange-ish looking and oily. I replaced the outer seal and changed to diff fluid to purple. It is still leaking. I don't know what it could be.

I have 186k on my Envoy. I replaced the valve cover gasket recently, the 6 coil packs, the outer driverside seal, changed the front diff fluid, added a trans cooler, dropped the trans pan and did a filter change.

The leak is coming from somewhere on the driverside oil pan/differential area. There is a little smoke where the oil pan seals which I assume is the oil being hot after running it.

I do not know where to go from here...


I drove it around the block and parked it and it was leaking. Wiped it all down let it sit for an hour, no leak. It has to be while it is warm..

 

[triz]

I noticed a leak that ran down onto my front differential case. It is orange-ish looking and oily. I replaced the outer seal and changed to diff fluid to purple. It is still leaking. I don't know what it could be.

I have 186k on my Envoy. I replaced the valve cover gasket recently, the 6 coil packs, the outer driverside seal, changed the front diff fluid, added a trans cooler, dropped the trans pan and did a filter change.

The leak is coming from somewhere on the driverside oil pan/differential area. There is a little smoke where the oil pan seals which I assume is the oil being hot after running it.

I do not know where to go from here...


I drove it around the block and parked it and it was leaking. Wiped it all down let it sit for an hour, no leak. It has to be while it is warm..

Orangish color would likely be coolant. Check around the pulleys. Most likely your water pump.

 

[sarg]

So if the outer driver's side axle seal is replaced and you still have a leak from the diff the only other two culprits are the inner seal and the pinion correct? Other than maybe the fill plug? With the aid of some nice pics from Roadie and others I managed the outer seal the other day and replaced any lost fluid, but I might still have a leak. Not sure at this point, but I did notice some fluid on the under side when back under there today doing the transmission cooler. I am REALLY not looking forward to having to do that inner seal. From what I can tell, pulling the front diff is a royal pain. Is it possible to change the inner seal with the diff still in the truck?

 

[The_Roadie]

The seam where the case halves come together can also leak. No gasket - factory used rtv. Small weeping I'd seal with JB weld.

 

[sarg]

I really need to decrease the crap out of it and see if I can tell exactly where it is coming from.

 

[PProph]

It is semi-common for the pinion seal to go as well or so i've read, i believe mine is seeping slowly.

 

[sarg]

Good to know. I just replaced the axle seal and I am hoping it is just residual fluid, but I guess I will not know until I get it all degreased and pressure washed.