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Joining the rear diff club

dsimoneaux19d

New member
2
0
1
Texas
Buick Ownership
2019 Regal TourX Essence
Completely different differential as ours is sourced from GKN and is mechanically different.

There doesn't need to be acknowledgment from GM or a TSB as you're having an issue that can be reproduced. TSB's are issued when there are enough failures and help guide the dealer toward the correct repair.

My tech sent an email to GM's technical line and was told to replace the differential under warranty. My pinion seal was leaking and that's serviceable in the field. The diff is not field-serviceable so it got replaced.

Sounds like you need a new service writer or escalate it to the service manager.

Appreciate the reply. As far as I know they have contacted the technical line, that's where the Corvette reference came in. He said it'll more than likely get replaced, they just have to go through all the steps they were given to diagnose it.

I'm going to let them do their thing, I used to be a tech at a dealership and getting through all the red tape takes time. I just figured there might be more out there with the issue... not on this forum...and maybe GM had taken notice to put something in writing.

One question for you though since you've been through this process... What kind of warranty came with the repair?
 

ChibiBlackSheep

Active member
188
124
43
Southeast, PA
Buick Ownership
Regal TourX Essence | Moon Blue Metallic
Adding myself to the list. Noticed diff fluid leaking on my driveway, the whole case was wet.

Just dropped my car off today, was told the seal is non-serviceable, and they are replacing the whole differential and bearings.

2018, Essence, 21,000 miles.
 

jdoodle

Sustaining Member
57
30
18
Texas
Buick Ownership
2018 regal tourx
Adding myself to the list. Noticed diff fluid leaking on my driveway, the whole case was wet.

Just dropped my car off today, was told the seal is non-serviceable, and they are replacing the whole differential and bearings.

2018, Essence, 21,000 miles.

That's strange, they just replaced the seal in mine a couple of weeks ago. Was yours leaking from the left side?
 

ChibiBlackSheep

Active member
188
124
43
Southeast, PA
Buick Ownership
Regal TourX Essence | Moon Blue Metallic
That's strange, they just replaced the seal in mine a couple of weeks ago. Was yours leaking from the left side?

Not sure what side it was on since they said they will be replacing everything for me. I'll try to remember to ask when it is done and I pick it up.

Curious how long I'll be without my car, because they said the parts are all in Michigan and the LCAs took a while to deliver.
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ChibiBlackSheep

Active member
188
124
43
Southeast, PA
Buick Ownership
Regal TourX Essence | Moon Blue Metallic
Update, dealership has had my car for 3 weeks now, and still doesn't have all of the parts to complete this repair yet...

They said they have the differential case, but not the axles. Hopefully they will call soon with an update.

Side note. My rental is a brand new Encore... I hate it.
 

Kappy

Member
69
33
18
Michigan
Buick Ownership
2018 Regal TourX
After reading this post, even though I am having no noise issues, I took a look at the rear diff. Sure enough it is leaking. Have an appointment to take in next Tuesday. 2018 X with 16k miles. I would recommend everyone with an "X" take a look, check your garage floor for drips before your warranty runs out. See pics
 

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jwillis1204

New member
4
3
3
Buick Ownership
2019 Regal GS
My rear diff had been getting quite chatty for the last few months, with no visible leaks. At 45k miles, I finally dropped the car off at the dealer to get it looked at. After almost a full week, they managed to change the rear diff fluid--and had the gall to charge me for it. They claimed GM "doesn't cover fluid breakdown". Obviously I'm litigating that out with Buick customer service.

The car drives about 1000x better with a working rear diff. It's amazing how much of a boat these cars are without the magic of torque vectoring. Also blows my mind that no warning lights were ever triggered.

Before I knew the dealer would get greedy, I'd also asked them to service the transmission and PTU/transfer case. I'd noticed the car seemed to be lugging more up mild hills--just chalked it up to carbon buildup. Literally all of that cleared up after the transmission was serviced. I seriously wonder if the 9 speed has the same issues with torque converter shudder as the longitudinal 8 speed does.
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Kappy

Member
69
33
18
Michigan
Buick Ownership
2018 Regal TourX
update on leaking diff, dealer had for 5 days, they replaced the left rear seal. Durning the time they had it, they changed the oil & rotated tires, also fixed an issue I had with the drivers seat. Loaner was a Cadillac XT5. Very satisfied.
 

Miltownsho

New member
18
10
3
Buick Ownership
18 Regal GS
My rear diff had been getting quite chatty for the last few months, with no visible leaks. At 45k miles, I finally dropped the car off at the dealer to get it looked at. After almost a full week, they managed to change the rear diff fluid--and had the gall to charge me for it. They claimed GM "doesn't cover fluid breakdown". Obviously I'm litigating that out with Buick customer service.

The car drives about 1000x better with a working rear diff. It's amazing how much of a boat these cars are without the magic of torque vectoring. Also blows my mind that no warning lights were ever triggered.

Before I knew the dealer would get greedy, I'd also asked them to service the transmission and PTU/transfer case. I'd noticed the car seemed to be lugging more up mild hills--just chalked it up to carbon buildup. Literally all of that cleared up after the transmission was serviced.

They are correct to charge you. Warranty doesn't cover maintaining your vehicle. Differential fluid along with transmission fluid should be changed every 45k. This is standard on almost any GM severe service maintenance schedule.

I worked at GM for years and will be changing my fluid at that interval as well.
 

RyeLou

Member
52
24
8
Detroit, MI
Buick Ownership
'18 Regal GS
Are you saying that the Chevy Dealer is ordering the part and doing the repair under warranty?

I once spoke with my local Chevy dealer who told me that they could NOT do warranty work on the Buick. They could service, but not warranty work.

Who is right?

I know the link is about the extended warranty, but the second paragraph answers your question. Any GM dealership has the ability to service and warranty any other GM brand vehicle.
 

Hunter Mike

Well-known member
437
282
63
America’s Dairyland
Buick Ownership
Dark Moon 19 Buick Opel Vauxhall Insignia Country Tourer Regal TourX Essence Estate Avant Wagon
Stopped by the dealer who replaced the rear diff in my TourX today to get some PTU fluid. Started talking to the parts guy and the tech who did the work and found the differential was never sent back to GM. Went around back and there is was! Loaded into the back and it’s now home with me.

I figure a new pinion seal and fresh fluid and it’s good to go. Pinion was leaking and it was groaning were the reason for replacement under warranty. Another member noted that fresh ACDelco fluid cured the noise and the seal looks easy enough to change.

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Voyager989

New member
3
1
3
Buick Ownership
Regal TourX
Have an appointment next week, horrible groaning noise while turning, instantly vanishes shifting into 'N'.
 

Hunter Mike

Well-known member
437
282
63
America’s Dairyland
Buick Ownership
Dark Moon 19 Buick Opel Vauxhall Insignia Country Tourer Regal TourX Essence Estate Avant Wagon
Have an appointment next week, horrible groaning noise while turning, instantly vanishes shifting into 'N'.
That’s a clear sign. Mine did the same thing. The PCM/TCM shuts off control for torque output to the rear diff when in N. noticable during slow turns from stop to the right, not left. It’s because the clutches have lockup control on the left output. Ask to have the tech ride around the parking lot and it should be obvious.
 

Jack GS

SUPPORTING MEMBER
591
727
93
Metro Detroit
Buick Ownership
2019 Regal GS
Apart from @jwillis1204's GS, where a drain and fill took care of the problem, the rear differential issues seem to only haunt the TourX. I know we have a larger TourX presence on the forum, and it's only a small sample of the population, but I find it odd that members with AWD Sportbacks and GSs haven't chimed in with issues.

From what I can tell, we all have the exact same rear differential. Between the AWD Sportback and TourX, the transmission and PTU are shared. I would assume the driveshaft angles are the same since the wheelbase is also identical.

Any ideas as to what makes the TourX (seemingly) more susceptible to these rear diff. issues?
 

Hunter Mike

Well-known member
437
282
63
America’s Dairyland
Buick Ownership
Dark Moon 19 Buick Opel Vauxhall Insignia Country Tourer Regal TourX Essence Estate Avant Wagon
Weight?
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BenD

Active member
309
126
43
Buick Ownership
2019 Regal GS
So many parameters; out of round parts (above tolerance), missalignment, Bad ratio, weight like Mike wrote (Not strong enough), I also have a big doubt about the width of the wheels used vs the vehicle equipment (hub, brake disk and wheel bearing/ size an grade) possibly the force caused by these large wheels exerts a pressure that the elements have a hard time handling. I dont remeber if its on that forum that i read something about a wheel recall for the Insigna or Commodor ????I'm still having issues with my GS, after forced balance on summer, winter tires, tires permutation bla bla bla, still the same sound of an unbalanced wheel. The "T1" message still there on the PicoScope. Now i'll ask them to do the measurment on each stud, hub, brake disk, i also asked them to use another set of wheel just to throw away the wheels element, which seems impossible for them! I haven't finished with them yet !!
 

Hunter Mike

Well-known member
437
282
63
America’s Dairyland
Buick Ownership
Dark Moon 19 Buick Opel Vauxhall Insignia Country Tourer Regal TourX Essence Estate Avant Wagon
GKN makes the same rear diff for the Ford Focus RS. Has anyone looked to see if they are having similar failures?
 

Rhetoric

SUPPORTING MEMBER
866
615
93
MPLS
Buick Ownership
Red Needle TourX
This reminds me of the AMC derived 4.0L inline 6 in the Cherokee, Grand Cherokee & Wrangler. From 00-03 the 4.0 in the Cherokee suffered from many cracked cylinder heads, but the GC and Wrangler of that era had basically no issues. My unsubstantiated hypothesis is TourX is using a certain lot from GKN diff, where the SportBack and GS are using other lots of the GKN diff.

My other hypothesis is that with all the moving parts it's totally random. Sometimes you get a bad one every so often. :p

I'm just glad to be on a message board where folks (unfortunately) are able to report this stuff so I know what to listen/watch for and can get it taken care of under warranty.
 
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