Guys I have an 02 suburban and today I notice that there is a small oil spot under the drivers front. Looked underneath and the whole drivers side caliper and axle (stubshaft?) and cv boots are covered in something.
Put it up on the lift and it smells like diff fluid. I inspected bth cv boots closely and find no cracks or apparent leaks from them, but dont they have grease in them instead of diff fluid anyway?
This crap is on the inside of the rotor, and all over the a-arms. Is the axle hollow and allows the diff fluid to go from the center diff out to the ends? Is there a seal or something behind the rotor? Any help on what to replace would be great! Thanks, Ron

 

Could it be a Seal on the Differential housing?

 

From the service manual:

"Front Axle Lubricant Leak Diagnosis

Front axle lubricant leaks can occur at the following locations:

• Axle shaft oil seals
• Differential carrier assembly mating surface
• Drain plug
• Fill plug
• Inner axle tube assembly to differential carrier assembly mating surface
• Pinion yoke oil seal
• Vent tube

Determining the Cause

While most front axle leaks may be easy to find, determining the cause may not be. A thorough inspection of the area around the leak may assist in determining the cause of the leak.

Oil Seals
Lubricant leaks from a oil seal may be caused by any of the following:

• An improperly installed seal
• A distorted seal
• A worn seal
• A worn shaft
• A brittle seal lip
• A hardened seal lip

To determine the actual cause of the leak, clean the area around the leak. Observe the area of the leak and determine the if the seal or another component is causing the leak. A worn seal surface will cause a leak at the sealing lip while a misaligned seal or a seal installed into a housing with an excessive bore will cause the seal to leak at the outside surface of the seal. Hardened or cracked seal lips usually indicate the axle is operating beyond the normal temperature limits for the axle. A seal whose sealing surface has been nicked or cut may indicate that the shaft has a rough, burred, or gouged surface and will need to be inspected before the seal can be replaced.

Sealing Surfaces
Front axles components are assembled using specific sealers. A leak at a surface sealed with sealant is usually caused by a poor fit of the components but can also be caused by the use of the wrong sealant. When correcting a sealant leak, inspect each component for distortion and for nicks or gouges that may prohibit the sealant from sealing properly and when re-assembling the component, use the proper sealant.

Differential Carrier Assembly
Lubricant leaks at the differential carrier assembly can occur at the following locations:

• Drain Plug
• Fill Plug
• Vent tube

Drain and fill plug leaks are usually caused by a loose plug. A vent tube leak can be cause by a loose fitting vent hose or by a vent tube assembly whose interior shield is stuck in the upside down position. Inspect the vent plug's interior shield for unrestricted movement, repair or replace the plug as necessary. Drain or fill plug leaks can be repaired by either tightening the plug or by using an approved sealer on the threads on the plug."

 

Dr X, from reading your post it sounds like it could be the axle shaft oil seals. I did buy a Haynes manual and it mentions the seals briefly, but goes on to say that "special tools" are needed and they recommend taking it to a dealer. Anyone replaced these before and can give me a heads up on what I'm in for? Thanks, Ron

 

PM bigbadwolf54 if you don't get any other help. He used to be a GM tech and can probably give you some info.

 

i had my driverside axle seal go out, fairly easy to replace, now my passenger side has gone out (leaking) if you read you owners manual, at some point, ever service interval you are suposed to inspect them, so obviously they suck

 

I've also seen shocks go out and do this.

 

The shock was my second guess, first was the power steering leaking......but it smells like diff fluid which is pretty distinctive. This only started after we got a little snow here and I used the 4wd auto. Doesnt appear to be actively leaking since I have been back in 2 hi for the past few days. Stone150, did you need anything special to replace the oil seals? I have replaced one in the rear end, but I'm lost on the front end. Thanks, Ron

 

I've changed the seal in the passenger side once. It was no big deal. The drivers side looks like you would have to split the case to get the axle out. A bigger deal but shouldn't be to bad.

 

Anyone know where I can get an entire rebuilt assembly that I can just bolt in and replace what I have now? The truck has 90k on it, If I can get them reasonable, I would just replace both sides and be done with it. Ron