Front Differential Oil Seal Repair Warning

[m.mcmillen]

Lately, I've noticed a few that have been noticing an oil leak on the driver's side of the front differential. I just wanted to warn those that attempt the repair of something I found.

A friend from work just picked up a Trailblazer that had supposedly had just had the front differential replaced. He noticed a while back that the driver's side seal was leaking so I took it apart to change the seal. I got started and noticed that the CV axle was not in all the way and neither was the seal. Further inspection found that the needle bearings in the adjuster nut were trashed. I also noticed the splined end of the CV axle was ground up.

All this to warn you to be sure you get the CV axle seated properly in the differential. I went ahead and replaced the CV axle, needle bearings, and the seal. The oil had a silver tint to it. I drained it and flushed the differential and refilled it as well. Unfortunately, the damage was too severe. I went for a drive in a gravel parking lot and found that as soon as I engaged the four wheel drive that there is a loud clicking noise coming from the left side. I think that the splined part of the differential side gear is stripped out.

So, please be careful! Luckily, I found a differential at the salvage yard with only 40,000 miles on it for $200.

 

[Mooseman]

Just thinking out loud here. As a preventive measure, after inserting the axles, would giving it a tug be a good test as to proper insertion? We all know that they need a good smack to get them out when properly locked in. If it doesn't come back out by hand, I would assume it's in right.

 

[m.mcmillen]

That is what I normally do. You could also pry against it lightly to see if it pops back out. It would also be a good idea to examine the retaining ring to be sure it is in good condition.

 

[m.mcmillen]

I changed it out a few days ago. I took the old differential apart. It appears there was more going on than the stripped splines.

 

[TollKeeper]

Boy that input is JUNK, and likely all the other bearings in there too. Good thing you replaced it!