AWD Makes Noise Near Rear of Car when Turning at Slow Speeds

[2007LucerneCXL]

Did they put it in writing that they authorized it to be used and are responsible for any occurrences?

 

[L J]

Did they put it in writing that they authorized it to be used and are responsible for any occurrences?

Doubt they will do that. But if you can document that part was ordered, and they did not rent you a car to use... Probably that would be good enough proof of their liability if something bad happens.

 

[2007LucerneCXL]

Liability comes in the proof that the dealer said it was safe to operate. A small detail but in the event something does happen it's on the owner of the vehicle, just a observation.

 

[Hunter Mike]

So.....I just wrote a ticket on my car (2018 GS 17000 miles) last week and had our techs check it for this EXACT concern. Ultimately, the rear diff fluid was just changed out. However, my tech came to my desk and told me to come take a look at something when he drained the fluid. In all the years I have been writing service, I have always known Diff fluid to be clear or brown, depending how dirty the fluid is. What I saw come out of my rear diff was JET BLACK. Neither my tech or myself had ever seen this before. He said GM was telling him to just change the fluid.

Based on your post I changed the rear diff fluid in the TourX this morning. I love the smell of sulphur in the morning! Car has 6003 mostly highway miles.

The change is pretty easy except the rear sway bar is pretty close to the fill plug. Not enough room for a 10mm hex socket, I had to break out the old trusty Craftsman ball-end hex wrench.


They are only tightened to 18 ft-lbs so the fill and drain plugs came out easy. My fluid wasn't pitch black and looked pretty good. The drain plug magnet was another story. I think it was pretty maxed out with ferrous material.



Overall a pretty easy job for anyone and only one tool was needed. It took right at a quart of Dexron LS fluid(capacity listed as 0.92qt). P/N 88862624 from GM. I used some Castrol 75W-90LS fluid that I had laying around and will report back if it doesn't get along with the clutches. I will probably change it every time I change the transmission fluid since it's easy and inexpensive. If you have a shop do it I would guess 1 hour of labor.

Edit: after a brief test drive with figure-eights on and off throttle I notice no issues using the Castrol fluid with LS additive in it. The OE fluid from GM is around $15 so it’s not as bad as the front PTU fluid at $50/qt! Must be unicorn tears.

 

[Map18TTourX]

Based on your post I changed the rear diff fluid in the TourX this morning. I love the smell of sulphur in the morning! Car has 6003 mostly highway miles.

The change is pretty easy except the rear sway bar is pretty close to the fill plug. Not enough room for a 10mm hex socket, I had to break out the old trusty Craftsman ball-end hex wrench.
View attachment 18716View attachment 18720

They are only tightened to 18 ft-lbs so the fill and drain plugs came out easy. My fluid wasn't pitch black and looked pretty good. The drain plug magnet was another story. I think it was pretty maxed out with ferrous material.
View attachment 18721
View attachment 18717View attachment 18718View attachment 18719

Overall a pretty easy job for anyone and only one tool was needed. It took right at a quart of Dexron LS fluid(capacity listed as 0.92qt). P/N 88862624 from GM. I used some Castrol 75W-90LS fluid that I had laying around and will report back if it doesn't get along with the clutches. I will probably change it every time I change the transmission fluid since it's easy and inexpensive. If you have the dealer do it I would guess 1 hour of labor.

so all i need is one of these?

Advance Auto Parts - Down for Maintenance

 

[Hunter Mike]

so all i need is one of these?

Advance Auto Parts - Down for Maintenance

Yup, unless you want to use the OE fluid. I would buy 2, just in case. if you don’t need it, return one. I used the Castrol equivalent.
You will need some way of getting the fluid into the fill hole. I used a short length of hose attached to the bottle but couldn’t get the last 100mL out so I was glad to have more on hand.

 

[Banjo]

Well I guess it cant Hurt, Stay Ahead of the Game and change that Oil.! Thanks for the heads up!

 

[JORDANSILVERNAIL]

Based on your post I changed the rear diff fluid in the TourX this morning. I love the smell of sulphur in the morning! Car has 6003 mostly highway miles.

The change is pretty easy except the rear sway bar is pretty close to the fill plug. Not enough room for a 10mm hex socket, I had to break out the old trusty Craftsman ball-end hex wrench.
View attachment 18716View attachment 18720

They are only tightened to 18 ft-lbs so the fill and drain plugs came out easy. My fluid wasn't pitch black and looked pretty good. The drain plug magnet was another story. I think it was pretty maxed out with ferrous material.
View attachment 18721
View attachment 18717View attachment 18718View attachment 18719

Overall a pretty easy job for anyone and only one tool was needed. It took right at a quart of Dexron LS fluid(capacity listed as 0.92qt). P/N 88862624 from GM. I used some Castrol 75W-90LS fluid that I had laying around and will report back if it doesn't get along with the clutches. I will probably change it every time I change the transmission fluid since it's easy and inexpensive. If you have the dealer do it I would guess 1 hour of labor.

Mine was in worse shape, if you can imagine that. My tech said he wants to just replace the entire assembly. He said if it sounds like the noise comes back even just a little, to write it up again. I guess we'll see what happens. he said it wont damage anything else.

 

[L J]

Since I am to lazy to look... let me guess its not on maint. schedule to change fluid every X miles?
What spec. fluid.... has my years old Mobil 1 75 W 90 full syn gear lube GL5 spec, not gonna do?

 

[Hunter Mike]

Lifetime fill, like the transmission it will last until the unit dies...after warranty.

If your M1 fluid is the LS version, fill away! If not, it's only $10-20 for a quart.

 

[Banjo]

Does LS mean Limited Slip in Regards to the Oil

 

[Hunter Mike]

Does LS mean Limited Slip in Regards to the Oil

yup. Dexron LS, Mobil 1 75w-90LS, Castrol Syntrax LS, etc. have the friction modifier for clutch-type LSD's in it already. If you don't have it, the oil is too slippery and may cause the clutches to chatter.

 

[CTMechE]

Is there a general opinion on whether the rear diff has a few bad units out there, or just that the 'lifetime fill' is way too optimistic for any use?

I'd be curious to know if other GKN Twinster cars have similar problems.

 

[Banjo]

I dont Understand why would it be a Lifetime fill if there are drain plugs on the unit.

 

[Idano]

I dont Understand why would it be a Lifetime fill if there are drain plugs on the unit.

Word from the Ford Focus RS forum is; their units will give a service needed warning in their DIC if the computer says the fluid needs changing. Their hotrods can put a little more abuse on the Twinster when they go drifting and the lifetime oil can need changing is my guess. It seems the fatter TourX might abuse it a bit much without even drifting. I wonder if we need a service the Twinster alert like they get ?

 

[mooooo]

That makes sense. My concern is my dealer wants me to continue driving the car until replacement parts come in. Should I insist I keep the loaner vehicle? They told me no components would be damaged when driving with a broken diff, but i am skeptical they just dont want to pay for the rental.

GM will reimburse them for the loaner. They don’t want to have one of their loaners unavailable for months. It also extends the warranty and runs the lemon clock. There’s no way in hell I’d drive the car.

 

[L J]

Lifetime fill, like the transmission it will last until the unit dies...after warranty.

If your M1 fluid is the LS version, fill away! If not, it's only $10-20 for a quart.

Thanks Hunter M..
It is LS, I bought it a long time ago for alot less then that.

 

[Hunter Mike]

I am updating my earlier how-to post to report that the rear diff is making noise enough for it to be replaced under warranty. It's probably about $2k to replace it. Joining the rear diff club

I don't know if the aftermarket Castrol 75w-90LS fluid contributed but I don't think I will stray from the OE Dexron 75w-90LS from here on out for the difference of $10/qt. It was also leaking from the pinion seal so there may be some incompatibility with the Castrol, or it could be unrelated.

 

[justinnow123]

The service manager estimated the repair of the rear diff to be about $8k when I asked him. Where did you hear/see the $2K number? That's a lot more manageable if this becomes a repeat repair out of warranty.

 

[Hunter Mike]

I guessed a little low if you need to include labor. List price on the rear diff assembly is $2,455, discounted online at $1,864.

R&R includes driveshaft, half-shafts, diff carrier, & rear exhaust removal. Suspension doesn’t appear touched so no re-alignment needed. There is reprogramming necessary of the module after install. I don’t have a labor guide so I don’t know what labor would be.