Gear oil compatibility for rear differential

[NLcamaro71]

I’ve read there is a service bulletin for the rear diff on 2010-15. It states dealer will change out gear oil with new synthetic oil, but the seals have to be replaced because the original seals are not compatible with the new oil. My 2014 SS has original seals, so I’m wondering, what aftermarket gear oils are compatible ??

[Quicksilver2SS]

I switched to Amzoil last year, no leaks on the original seals.

['10CamaroDude]

When you look for gear oil for it, they're all synthetic. You'd have to go out of your
way to buy conventional gear oil for it, like at a Walmart, or auto parts store. Having an
LSD, you also need the friction modifier. Some brands will have it in there already.

I haven't seen any TSBs on that, and from what I know, they're synthetic from the
factory.

[Black_SS10]

The TSB was for '10 to '11 year models that had complaints of diff chatter. The TSB states to replace the axle seals because they are not compatible with the replacement fluid. Yours being a '14, you're covered under the TSB as well.

['10CamaroDude]

I don't see how seals can cause that, they just keep it from leaking out, and are
no where near the clutch pack. That's so odd, and even odder if changing them
actually fixes the problem. I know fluid without the modifier causes it. Also, it
says only in reverse when turning. So, why not forward, if it's seals? That's so
odd...

[Black_SS10]

Originally Posted by '10CamaroDude

I don't see how seals can cause that, they just keep it from leaking out, and are
no where near the clutch pack. That's so odd, and even odder if changing them
actually fixes the problem. I know fluid without the modifier causes it. Also, it
says only in reverse when turning. So, why not forward, if it's seals? That's so
odd...

Replacing the seals is part of the TSB. They say they're not compatible with the new fluid....not that they are causing the chatter....hence the new fluid.

['10CamaroDude]

Really? The very beginning of the TSB says this:

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may comment on a chatter or moan type noise from the rear of the
vehicle while making low speed turns. This condition may be caused by a slip/stick of
the posi-traction clutch plates. As the plates slip and stick, a jumping or jerking feel
occurs, accompanied by a chatter noise.

Recommendation/Instructions.
Caution: The rear axle seals must be replaced. The original seals are not compatible
with the new fluid.

So, yeah, they seem to indicate RIGHT there, the SEAL is the cause. They don't say in
the first few statements, that the fluid needs changes to fix it, then in turn the seal
also needs changed because it is incompatible with the fluid you're going to need to
change over to. Just bad wording, or wrong order...

First, it reads like the seals are the cause, then they go ON, to say you need
to change the fluid... I know what the deal is, but that's not what it says initially.

[Black_SS10]

Wow....ok.

[Avenging Orange]

Either way.....I guess....unless you are experiencing issues, I would stick with what the owners manual recommends.
I changed mine to Lucas NONsynthetic w/friction modifier....no issues. But that's just me.

[Mouse330]

The 14 as well as my 11 came new with conventional oil in the diff. When I bought my car it had 56k on it with a slight chatter on slow turns. Most likely had the original fluid in it. I put a qt of royal purple max gear synthetic which has the additive in it already. I would say within a couple days it was gone. No leaks. Been in for 4-5k now

[Stingr69]

Originally Posted by '10CamaroDude

Really? The very beginning of the TSB says this:

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may comment on a chatter or moan type noise from the rear of the
vehicle while making low speed turns. This condition may be caused by a slip/stick of
the posi-traction clutch plates. As the plates slip and stick, a jumping or jerking feel
occurs, accompanied by a chatter noise.

Recommendation/Instructions.
Caution: The rear axle seals must be replaced. The original seals are not compatible
with the new fluid.

So, yeah, they seem to indicate RIGHT there, the SEAL is the cause. They don't say in
the first few statements, that the fluid needs changes to fix it, then in turn the seal
also needs changed because it is incompatible with the fluid you're going to need to
change over to. Just bad wording, or wrong order...

First, it reads like the seals are the cause, then they go ON, to say you need
to change the fluid... I know what the deal is, but that's not what it says initially.

You read that wrong. The positraction plates are making the noise. The new fluid fixes the plates from chattering and groaning. For literally decades, Posi plates have been known to chatter or groan around turns if the lube is not right. The old remedy 50 years ago was add the GM limited slip additive and drive some figure 8's to get the lube between the plates in the differential. That would stop the chatter.

The seals are not compatible with the new fluid. Need to change the seals so they do not fail after the swap.

I bet they have seen original seals leak if you do not change them when you swap the fluid.

[dianeokie]

Originally Posted by Black_SS10

The TSB was for '10 to '11 year models that had complaints of diff chatter. The TSB states to replace the axle seals because they are not compatible with the replacement fluid. Yours being a '14, you're covered under the TSB as well.

So, because there is a TSB, is there a charge for replacing the axle seals?

[Black_SS10]

Originally Posted by dianeokie

So, because there is a TSB, is there a charge for replacing the axle seals?

There shouldn't be. If the vehicle fits the criteria.