2020 GMC Sierra 1500 AT4 diesel rear main seal failure

[winnemucca]

With only 7,200 mi, my new truck is at the dealer service center right now because there was a rear main seal failure, and massive oil leak. How in the heck could this happen to a new car?

Edited January 5, 2021 by winnemucca

[Jsdirt]

Greed, basically. Automakers don't care about longevity - they want you back in the showroom as soon as possible. In their quest to save a few pennies on a part, sometimes they go too far, as with the AFM lifters, low tension piston rings, valve springs, the 3/4 clutch pack in the old 4-speed trannys, spider gears in the rear differential (and probably the front, too), rust prone body panels and undercarriage parts, ball joints, shocks, brakes,  and the list goes on ...

 

Sounds like they cut too many corners on that rear main seal ...

Edited January 5, 2021 by Jsdirt

[MaverickZ71]

Unfortunately, at today's GM, quality seems to be job none.  Consumer Reports just rated ALL of the new Silverados/Sierras/Colorados/Canyons in their "don't buy" category due to poor reliability.  Good luck.  

Edited January 5, 2021 by MaverickZ71

[Doug_Scott]

Contrary to what has been posted, vehicles today are far better build quality than days gone by.  I have bought new cars in the 70s, the 80s, the 90s, the 00s and the 10s.  Everyone of those vehicles went back to the dealer for warranty repairs except the last one.  Its been 10 years since I took delivery, and other than the rear window being replaced due to missing parts of the heated window strips that was noticed before I left the lot.  First vehicle to not require front rotors in the first 20k, actually been 10 years, still have original rotors.  

 

There is a reason they put warranty on new vehicles.  Sometimes there is a defective part.  ****** happens.  

[Jsdirt]

I think everyone in MA needs to find your car dealer, Doug! Not a single person I know, family or not, has had any luck with anything built after '96, and even less luck with stuff 2007 and newer. Not just cars, but refrigerators, snowblowers, lawn tractors - everything ...

 

You wouldn't believe the stuff I see every day. The older stuff is always running longer, so long as the owner keeps the vehicle oiled to keep it from rusting away to nothing.

Edited January 5, 2021 by Jsdirt

[Doug_Scott]

15 hours ago, Jsdirt said:

I think everyone in MA needs to find your car dealer, Doug! Not a single person I know, family or not, has had any luck with anything built after '96, and even less luck with stuff 2007 and newer. Not just cars, but refrigerators, snowblowers, lawn tractors - everything ...

 

You wouldn't believe the stuff I see every day. The older stuff is always running longer, so long as the owner keeps the vehicle oiled to keep it from rusting away to nothing.

I have a friend that is a retired GM employee, he bought a 04 Sierra SLT Ext cab in late 03, dealer had the factory ordered truck in under 2 weeks(helps that we are 10 miles from Oshawa plant), his only warrantee claim was an o2 sensor that failed as he was going through a car wash.  He also had his ignition key replaced because the plastic/rubbery part broke where the ring when through.  Then came my truck, then he bought a 2012 SLT 4x4 4 door along with his son getting a 2012 SLE 4x4 ext cab.  His son's truck had to have the leaf springs replaced due to one leaf breaking, outside of warranty.  He used his 04 truck to tow an enclosed trailer for motorcycle track days.  No warranty issues, and no transmission issues.  My last 4 new cars where in the 2000 and onward era, they all needed front rotors before 20k.  I live in the Canadian rust belt.  It may help that both him and I are licensed auto mechanics(we met working at a Chrysler dealership nearly 40 years ago).  

 

I get what you are saying about the stuff you see every day.  You have to remember that you don't see the cars that don't have issues, and I will guarantee there are millions more that you don't see.  Your reasoning was exactly the reason I bought a new Mustang in 78 while working at a Plymouth/Chrysler dealership as a transmission mechanic, every Plymouth I saw was broken, never saw a good one. 

[macu22]

On 1/5/2021 at 2:23 PM, winnemucca said:

With only 7,200 mi, my new truck is at the dealer service center right now because there was a rear main seal failure, and massive oil leak. How in the heck could this happen to a new car?

Curious what the outcome was here. My 2020 GMC Sierra Denali Diesel also just blew rear main seal at 4000 miles. Have had the truck for less than 60 days. The service advisor also told me they had another one exactly like mine come in right behind mine. Has yours been fully repaired? Was it just a bad part or something else that cause the failure?