Rear Diff change 15K

[Map18TTourX]

After reading about peoples rear diff's going bad. I decided to change my fluid out.

My Tourx is a White needle with 15K with only one mild winter under the car.

The fluid coming out was clean beige color.

The car took 1 Qt and 4 OZ. (so get two bottles)

 

[ChibiBlackSheep]

Is there a reason you didn't go for the transfer case too? Do you know if these cars require the additive?

I don't see any differential lubrication specifications in the owner's manual. I would much prefer do put ACDelco fluid in + the additive if required. Especially since you are saying it took 1L and 4oz, as the additive is usually a 4 oz. bottle itself.

 

[L J]

Is there a reason you didn't go for the transfer case too? Do you know if these cars require the additive?

I don't see any differential lubrication specifications in the owner's manual. I would much prefer do put ACDelco fluid in + the additive if required. Especially since you are saying it took 1L and 4oz, as the additive is usually a 4 oz. bottle itself.

I assume you are taking about limited slip additive?
Had heard not required with Mobil 1 full syn. gear lube, not sure if that is correct.

 

[ChibiBlackSheep]

Yeah the LS additive. GM sometimes sells the fluid and the additive separately, and doesn't necessarily like the all-in-one bottles. Like with my Camaro, it's recommended to use the fluid without additive and add the additive separately so that there is more in there.

 

[Map18TTourX]

LS on the bottle already has additive in it.

 

[ChibiBlackSheep]

LS on the bottle already has additive in it.

I know that, but it doesn't necessarily mean it meets the spec of the differential. I was just wondering if anyone knew what GM recommended goes in it, since I don't see it listed in the owner's manual.

 

[Jack GS]

I just had the engine, transmission, PTU, differential, and differential clutch fluids changed at 5k miles just for assurance. I know it isn't necessary but I sleep easier knowing all the fluids are in good shape after the break in.

Anyway, here's what they put in mine. I asked for all of the recommended GM specified fluids. No mention of any additives/modifiers.

Engine

DEXOS 5W-30 88865639​

Filter: 12690385​

Transmission

DEX6 ATF 88862156​

Trans Kit: 3066​

PTU: 19351882
Differential: 88862624
Differential Clutches: 88901975

 

[Ctrcbob]

I just had the engine, transmission, PTU, differential, and differential clutch fluids changed at 5k miles just for assurance. I know it isn't necessary but I sleep easier knowing all the fluids are in good shape after the break in.

Anyway, here's what they put in mine. I asked for all of the recommended GM specified fluids. No mention of any additives/modifiers.

Engine

DEXOS 5W-30 88865639​

Filter: 12690385​

Transmission

DEX6 ATF 88862156​

Trans Kit: 3066​

PTU: 19351882
Differential: 88862624
Differential Clutches: 88901975

I don’t have my owners manual here in front of me but know that the Sportback (9 Speed) and the
Tour-X (AW 8 speed) take different fluids.

 

[L J]

I just had the engine, transmission, PTU, differential, and differential clutch fluids changed at 5k miles just for assurance. I know it isn't necessary but I sleep easier knowing all the fluids are in good shape after the break in.

Anyway, here's what they put in mine. I asked for all of the recommended GM specified fluids. No mention of any additives/modifiers.

Engine

DEXOS 5W-30 88865639​

9

Filter: 12690385​

Transmission

DEX6 ATF 88862156​

Trans Kit: 3066​

PTU: 19351882
Differential: 88862624
Differential Clutches: 88901975

Guessing the dif. clutches is limited slip additive, since the clutches is why you need the additive.

 

[L J]

I find it hard to believe they put 16 qts in your transmission, not even if they got every bit of the old out.
But i know nothing about the 9 speed must have 12 qt pan.

 

[L J]

I just had the engine, transmission, PTU, differential, and differential clutch fluids changed at 5k miles just for assurance. I know it isn't necessary but I sleep easier knowing all the fluids are in good shape after the break in.

Anyway, here's what they put in mine. I asked for all of the recommended GM specified fluids. No mention of any additives/modifiers.

Engine

DEXOS 5W-30 88865639​

Filter: 12690385​

Transmission

DEX6 ATF 88862156​

Trans Kit: 3066​

PTU: 19351882
Differential: 88862624
Differential Clutches: 88901975

I think just glancing at invoice, they may have taken advantage of you.
Am I reading that right $600 to change fluids and maybe a filter and some gaskets?

 

[Hunter Mike]

Good work OP. My magnet looked worse than yours so definitely worth the $20 and the time.

 

[Jack GS]

@Ctrcbob, you're correct. They are different but I thought the data might be helpful nonetheless 🤷🏻‍♂️

@L J, it is my understanding that the differential gears and and clutches are separate systems, relying on their own lubricants (unlike a normal limited slip differential). The extra transmission fluid is required to perform the trans flush.

As far as the invoice, the labor really starts to add up. The parts prices are not off base. Until I have a sweet fleet like you, I can afford to let the dealership handle the services on the one nice car I have 🙃 I could have done it myself and saved a lot of money, but as I mentioned before, it was an assurance thing. Not the right way to do it, just the way I did it.

 

[L J]

@Ctrcbob, you're correct. They are different but I thought the data might be helpful nonetheless 🤷🏻‍♂️

@L J, it is my understanding that the differential gears and and clutches are separate systems, relying on their own lubricants (unlike a normal limited slip differential). The extra transmission fluid is required to perform the trans flush.

As far as the invoice, the labor really starts to add up. The parts prices are not off base. Until I have a sweet fleet like you, I can afford to let the dealership handle the services on the one nice car I have 🙃 I could have done it myself and saved a lot of money, but as I mentioned before, it was an assurance thing. Not the right way to do it, just the way I did it.

Sorry I should not have said anything, I know the dealers have to get the service dept. to
pay the overhead for entire dealership, or that is what I heard. I am pretty cheap because I live above my means.
Like everyone does, or should do...is do what you want how you want. As the song says...you can't please everyone so you might as well please yourself.

 

[Sweden]

Is it fine to go with random 75w-90 LS GL-5 like Mobil1 ?
Dexron LS / ACDelco 88862624 is pretty expensive in Sweden

 

[Hunter Mike]

Is it fine to go with random 75w-90 LS GL-5 like Mobil1 ?
Dexron LS / ACDelco 88862624 is pretty expensive in Sweden

After I changed mine the pinion seal started leaking and I got the dreaded groan while turning right at slow speeds.

Don't do it! My diff was replaced under warranty because of these problems. I didn't tell them I changed the fluid to non Dexron.😗

 

[kbtuba]

posted to 2018+ Buick Regal Sportback and TourX Forum

"So the dealer replaced the rear diff assembly, I don't really have any details beyond that. I had not been looking for leaks, nor had seen any drips or other signs. I had the 'groan' noise, first while turning right, later thru all acceleration, but I can't say that I ever felt a difference in performance. The dealer confirmed that this would be covered under the drivetrain warranty, so I'm just going to keep a eye out for future and hope the whole problem came down to a bad batch of parts."

 

[Sweden]

After I changed mine the pinion seal started leaking and I got the dreaded groan while turning right at slow speeds.

Isn't this happening with factory OE oil too?