Tourx - Rear Diff Concerns

[Buicurious]

I am considering buying a Regal Tourx (I have my heart set on a white needle in Rioja Red Metallic) but can't help this feeling that unless something changes in the near future this will not be a car to own outside of warranty. There are two wagons on the used market right now that received new rear differentials right around 60k miles and were promptly listed for sale based on their Carfax reports. I have tried to educate myself on the topic, but I think every forum post I have seen indicated the solution was to replace the rear diff, and no one is repairing them. Has anyone figured out what is causing the differential failures, are the differentials rebuildable, or should owners expect to pay $2-3k every 50-60k mi?

I have owned German vehicles in the past that people might consider high maintenance but I am used to offsetting maintenance costs by doing the work myself, and even if I did repair or replace the rear diff myself it sounds like I would have to take it to the dealer to have them reprogram the control module. Did I miss any posts where the flaw was identified, or someone was able to rebuild a failed diff?

Edit - Sorry if this should have been posted to the "joining the rear diff club" thread, since that seems to house all the information.

 

[94cruiser]

Purchased my car with 7 or 9 K miles, can't recall.
Soon after it has developed a leak in the diff, and the slinger was replaced.

https://www.youtube.com/watch?v=aFhfgxqQUxU
34.5k first rear diff replacement
a year later another replacement

I'm at 60k now.

 

[CPO]

96k, no problems so far.

 

[Buicurious]

@94cruiser do you know if either of the replacement differentials were the updated part numbers?

 

[94cruiser]

Since purchased the car I kept all maintenance records. I will dig through to see if they list the part numbers.
At each service that has warranty tied to it, the dealer RO copy has more pages and more information. I was able to only look at it, and sing.
I know the job parts and labor costs is into several thousands.

 

[Buicurious]

@94cruiser thanks for posting the video, it is helpful to know what to listen for on a test drive. Please let me know if you are able to find the maintenance records.

 

[94cruiser]

From the October 2023 repair


86506324 5505BK CARRIER

www.gmpartsdirect.com shows this as $1,382.41 part.

 

[2018 TourX in Texas]

Please see my posts & pics / YouTube video on this matter !

Basically my Groaning / about to fail diff issue was addressed by a fluid switch.

Look at page 17 of the "Join the Rear Diff Club"

Let me know if what I posted makes sense.

David in Texas

 

[Buicurious]

Thanks, David. I saw your post and watched the youtube video. Very exciting to see that it might just be a fluid issue, but now I wonder how to determine what is the correct fluid to use?

 

[Special Deluxe]

I have a 2018 I bought in Jan 2020 with 7000 miles. While getting an oil change had my local mechanic check the rear diff fluid at 60,000 after reading the forum. Oil was splattered on the undercarriage, but no drip. Refilled the diff with fresh oil. Never made noise or caused problems. Now he checks it at every oil change. No issues so far.

 

[2018 TourX in Texas]

Thanks, David. I saw your post and watched the youtube video. Very exciting to see that it might just be a fluid issue, but now I wonder how to determine what is the correct fluid to use?

#888 626 24 I believe is the # I show in the video & also read the last few posts in the "Joining the Rear Diff Club" thread - guys are posting the fluid PN# there too.

I think I got a bad bottle from a bad batch - if you saw my YouTube video it must've been cause of the result.
EDIT - yes that's correct PN & also it goes by AC Delco 10-4034.

Here's Amazon listing

https://www.amazon.com/ACDelco-10-4034-Dexron-75W-90-Gear/dp/B008BZS6J8

 

[adam728]

#888 626 24 ........ goes by AC Delco 10-4034.

Here's Amazon listing

https://www.amazon.com/ACDelco-10-4034-Dexron-75W-90-Gear/dp/B008BZS6J8

Exactly what I used and where I purchased it. I really wonder what you got that gave issues?

My experience is in the other thread, but the short version is

• Dealer fluid change (with pinion seal), and about 60K later it got noisy. Tight turning, especially left, groaned, and sometimes even slightly shuddered the car (like a clutch-based limited slip going out, or on the wrong fluid).
• Changed to Valvoline gear oil with limited slip additive while awaiting the AC Delco oil. 60K fluid looked pretty clean, and just a light slurry of goo on the drain plug. Fresh oil changed nothing. Still noisy. I was worried.
• AC Delco oil arrived, changed again (about 1K and 2 weeks on the Valvoline). Oil came out looking great. Noise was immediately cured with the AC Delco.
• Close to 4K on it now, still quiet and performing fine. Keeping fingers crossed. I don't abuse the car, but I do not baby it either.

 

[DoUSail2]

Is only one quart required. Remove drain plug on bottom to drain and fill to spill for the upper plug? Thanks for a reply

 

[G-368385]

I am considering buying a Regal Tourx (I have my heart set on a white needle in Rioja Red Metallic) but can't help this feeling that unless something changes in the near future this will not be a car to own outside of warranty. There are two wagons on the used market right now that received new rear differentials right around 60k miles and were promptly listed for sale based on their Carfax reports. I have tried to educate myself on the topic, but I think every forum post I have seen indicated the solution was to replace the rear diff, and no one is repairing them. Has anyone figured out what is causing the differential failures, are the differentials rebuildable, or should owners expect to pay $2-3k every 50-60k mi?

I have owned German vehicles in the past that people might consider high maintenance but I am used to offsetting maintenance costs by doing the work myself, and even if I did repair or replace the rear diff myself it sounds like I would have to take it to the dealer to have them reprogram the control module. Did I miss any posts where the flaw was identified, or someone was able to rebuild a failed diff?

Edit - Sorry if this should have been posted to the "joining the rear diff club" thread, since that seems to house all the information.

Don't do it! Mine is sitting in my driveway in need of over 5000$ for a new rear differential! It's sealed so only the dealer can do it and no one else will even consider touching it.