[camaroz06]

Hey everyone,

Looking for some opinions. I went in to get my diff looked at because I saw a splotch of diff oil on the ground when getting the car out of storage. Was about a credit card size splotch, after I saw that I checked under the car and saw the diff was wet and wiped it down. Parked the car for a few days and didn't see any new drips on the floor....so I was thinking "oh maybe a seal or something" because I had a rear axle replaced 4 years ago and the damage was listed as "driveshaft flange found separated from differential and damage to splines"

Fast forward to the first call today w/service after dropping the car off the dealer tells me I need to replace the same axle again and is causing the leak. I mentioned, can you dig into this more? It doesn't make sense to replace the same axle in under 1000 miles (I don't drive much over 4 years) to have failed again. They dig a little any tell me to replace the rear diff because its having trouble holding the axle. Does that diagnosis make sense? I'm by no means a tech but it doesn't sound far fetched to me that the diff is having issues with the shafts or something and was the original problem too...

Thanks for any advice

 

[kittyboy]

Could be it was an incorrect diagnostic the first time, I would have it inspected at a different dealership for a second opinion.

 

[RobF300]

i doubt you need a new diff, unless you have some extended warranty coverage that will cover this pull the car out of there

 

[RocketSled]

"The Diff is having trouble holding the axle" doesn't make a lot of sense. New Dealership Service Department needed.

 

[Sudderth]

This could be the seal was damaged when they did the install originally. Remove the axle and polish the seal surface and replace the seal and make sure to lube the seal surface before installation.

 

[djdonte]

Differentials dont just stop "holding the axle." They either damaged the axle seal on the diff, or damaged the finished machine surface on the shaft that seals against it. There is also a C clip that holds it in the diff. Maybe that is missing?

 

[MrSurly]

Your dealer's dishin up the balderdash. First, the diff doesn't actively "hold" the axle.
The diff has a side gear in it (two of them) and the ID of the side gear has a splined bore through it. About an inch deep in that spline bore, there is a groove cut circumferentially. That groove is the only thing that might be referred to as having the job of 'holding' the axle but it really isn't much of a task as the axle is NOT trying to get out.
The axle stub shaft is splined and about about 3" long. It has a groove in it and a spring wire "snap ring" or 'C clip' is installed in that groove of the axle. The clip engages the groove in the side gear's spline bore when installed. When removing the axle stub from the diff, the interference of the clip in the groove WILL add a teensy bit of resistance to the stub being pulled out...but truthfully, while the car is assembled, and the axle is not actively being removed by a mechanic going through a lot of trouble doing other work to do this, the axles are held in place by other means. Meaning the axles are 'captive', and the rings/clips/grooves/side gears don't actively retain them. Speaking simplistically: there's 'three foot of axle in a two-foot space'. It ain't gonna fall outta there until someone removes a foot of stuff. However, if the clip were missing altogether, the axle stub might be able to walk in and out of the seal slightly and this could lead to early seal wear.
I think I would have them change the axle seal AND when doing this, make sure that the snap ring is replaced.
It sounds like your diff likely needs an axle seal replaced. Of course, one might speculate that a shop might make a little more money selling you $4000 in parts than they would make selling you a six dollar seal.... but I'll leave the speculation to others.

 

[MrSurly]

Additional food for thought: My diff whined (100K+ miles) and I did buy a brand new GM differential unit. Immediately upon install I found the new diff to whine slightly and VIBRATE heavily at speed.
So, given that your diff is original; low mileage; quiet; smooth; there is NO WAY I'd replace it with what is essentially a crap-shoot of a new unit.

 

[tinman]

I would continue to drive it 'as is'. Make sure the pumpkin is full. I'm not as well versed as others here, so take my advice with a grain of salt. But you can always pay $4000 anytime to repair it if it takes a dump, which I doubt it will

 

[ReMiXeDg]

I'd have to agree with tinman what he mention sure does make sense and sounds good. I'd do just as he suggested use it like that till either it whines loud or just goes out on you. You probably have some more life out the one that is currently installed on the car. Just keep your eyes and ears out for it.

 

[ThunderOne]

the axle is causing a leak? sounds to me like the dealer fucked up the original install and messed up the diff seal. whether or not you ran the diff dry is another question, but sounds to me like it's the stealership's fault. since it happened so long ago you probably won't get them to do fix it for free, but a diff seal should be a cheap job.

 

[Sudderth]

2008-2015 Cadillac CTS Rear Axle Shaft Seal 25995847 | TascaParts.com

2008-2015 Cadillac CTS part # 25995847 - Rear Axle Shaft Seal

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