after adding 80-90 syn gear oil to the front differential of my 90 f-250 4x4, it started leaking. Do not have time or money right now to tear it apart or pay for repair. Is there any hope that a "stop leak" type sealant will work?

Thanks!

 

Stop what you are doing and back away from the truck.

Now, did you do anything while you were in there, other than adding fresh oil? Where is it leaking from?

 

Is leaking from behind the 10 - bolt circle - dripping off the lip that curves to the rear that runs under the differential casting, not seeping from the bolts themselves. Did nothing but add oil. Could be that the leak is in upper portion of seal, and when I added oil it filled up over the poorly sealed section and will leak down to the sealed area? I did check the axle shaft and drive shaft seals - no leaks from there.

 

You're going to have to drain it once more, and replace the seal around the pumpkin. Go to any auto parts store and ask for a front differential gasket.

 

Be sure that the fluid that is leaking is actually differential fluid. When changing the oil filter on my 5.0-the engine oil that leaks from the open oil filter base on the engine block ends up leaking down to the axle assembly -just like you described.

I would think that if you overfilled the front differential-it is possible that the axle fluid could heat up and expand and leak out of the vent fitting on top of the differential (especially if the hose that is normally on this fitting is missing) and cause this same type of leakage.

Or the vent to the front differential housing isnt open and causing the axle differential housing to pressurize and forcing the axle fluid pass the differential housing seals.

I bet that the leakage is caused by overfilling. Try removing the fluid again and making sure that you get all of it out-before replacing with the correct amount.I always measure the amount that comes out-especially when the front differential is involved.

And make sure that the truck is on level ground before removing and replacing fluid.

 

Thanks for the replys, Guys!

Overfilling sounds like the culprit. I don't think its engine oil - as it is very clear and feels like 90 wt. When I filled it the truck was on a slant.

Where is the tube and vent?

If I do have to replace the seal how much of a PITA is this job?

Northwoods

 

The vent fitting and hose will be on the top of the differential housing. If you filled on unlevel ground-you probably overfilled. Measure what comes out and measure what amount goes in. It is easy to overfill the front differential-since there is no drain plug. And it isnt possible to remove an inspection plate like the rear differential.

Hopefully-just getting the correct amount of fluid in the differential will stop the leak.

Have you engaged the front differential since this leakage started?? If not-then operating heat expansion of the fluid wouldn't have been an issue.

I believe that overfilling is the issue also.

 

Contrary to popular logic, filling until 90wt runs from the fill hole is overfilling........level is supposed to be about 1/4" BELOW the fill hole to allow for heat expansion. Most likely, everyone here is right.......its just overfilled.

 

there is no vent on the differential that I can see. I took a closer look at the left shaft where it enters the case - looks like this is where the leak is coming from. Unless this would be caused by overfilling, it looks like I have a seal to replace.

Is this a big job?