Topic: Overfilled diff causing leaks?

[Ghettofab88]

Has anyone had pinion or axle seal leak issues from overfilling their diff fluid?

I've got an 88 pickup I just  built a new axle housing and e-locker diff for and I have a persistant pass side axle leak and pinion seal leak.  I trussed the housing and used an alignment jig to make sure its straight.  Because I run a CV rear driveshaft with the pinion pointed up at the t-case I decided that moving the fill plug up would be a good idea to help keep pinion bearings lubed.  I'm running 4qts of gear oil in the axle which still isn't halfway full.  I just checked the vent line and its good, no oil in line either.  I've replaced both seals with the marlin seals and 2 weeks later its still leaking.

I'm just wondering if running an extra qt of gear oil would make that much difference?  I can't imagine that it would make that much difference to a pinion seal thats hopefully constantly bathed in oil any way.  It could be the yoke, but it looked ok, better than most, definately better than my non leaky diff I pulled that had 252K miles on it.

I've got a big trip starting may 31 and I'm tired of trying to make this thing work.  At this rate I'll have to take the chevy and not go wheelin.  This'll be the first time this truck has ever missed a trip in 21yrs.

Kevo

[junya92toy]

2.3 quarts in the rear. and yes it can. if you dont have a breather

[BUDDERS]

I've seen this issue with clogged breathers before.  It doesn't matter how many times you replace the pinion seal or the axle seals, it will still leak if the breather is clogged because the axle housing builds up pressure once the fluid gets hot and if that pressure doesn't have a functioning breather to escape from, it will use the seals as a vent - and usually oil will come out with the pressure.

[Ghettofab88 [OP]]

Yeah I know, thats why I checked the vent.  Its fine, no obstructions.  I actually drove it home with just the hose on their and no cap or filter and it still leaked.  BTW, this vent setup worked fine on my old axle that I had pulled out.

[*ROKTOY*]

I filled my diff till the oil came out the fill hole then added another Qt, I have had no problems.

[Snowtoy]

Did you check the fitting, it could be logged from the diff side?

Did you put the seals in correctly, might have torn one when installing the the axles?

[Ghettofab88 [OP]]

Yup, I can blow through the vent line into the axle housing with ease.

The new axle seal still feels good. Still has a sharp lip on it.  Don't know about the pinion seal though.  Its kinda hard to screw up the install on marlins seals.  They were lubed prior to use also.

I'm was going to change the diff fluid anyways so I think instead of putting 4qts in I'll just put 3 in and see what happens.  If it still leaks maybe I'll pull the flange off my old diff and install it on this one.

Kevo

[Ghettofab88 [OP]]

Ok so diff still leaked at 3 qts full.  I pulled the pinion flange out and started inspecting.  What I found was some pitting from previous rust on the seal surface of the flange.  Unfortunatley the new marlin seals are designed to push the seal further in towards the diff, usually a good thing as that area never sees any wear.  However, in my case that caused the seal to ride on the pitted surface.  I got a normal pinion seal from napa, cleaned the flange up a bit better this time and we will see what happens.

Axle seal doesn't appear to be leaking yet either. 

New tires should be hear friday and the truck should be good to go.

Kevo

[blackdiamond]

I thought the diffs only held about two  quarts?  I overfilled once and actually had it blow out the vent.