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Sierra Differentials

Cathy Wankel

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Cathy Wankel New Member

Cathy Wankel

Posted
Posted

Our 2017 Sierra blew a front differential and the dealer said that I had it in 4wd while pulling a trailer and that was the cause. I know for sure I didn’t have it in 4wd as I checked several times. Why I checked is because I was burning more fuel than usual and it felt stiff. I have pulled trailers for many years and even travelled for 3 1/2 years solely in a trailer. Has anyone had problem with it switch to 4wd on its own?

JimCost2014 Senior Enthusiast

JimCost2014

Posted
Posted
On ‎4‎/‎10‎/‎2019 at 8:35 AM, Cathy Wankel said:

Our 2017 Sierra blew a front differential and the dealer said that I had it in 4wd while pulling a trailer and that was the cause. I know for sure I didn’t have it in 4wd as I checked several times. Why I checked is because I was burning more fuel than usual and it felt stiff. I have pulled trailers for many years and even travelled for 3 1/2 years solely in a trailer. Has anyone had problem with it switch to 4wd on its own?

Welcome to the site.

 

Did you buy the truck new?

I would check with your dealer and see if there has been any updates (TSB's) done to the truck.

There are a few post on here about trucks being stuck in 4WD and the owners not knowing about, and other problems with the system.

truckguy82 Senior Enthusiast

truckguy82

Posted
Posted

So I just thought about how how the differentials operate and towing, and I have no idea how a front diff would be effected by towing. Towing actually takes weight off the front end

garagerog Enthusiast

garagerog

Posted
Posted
1 hour ago, truckguy82 said:

So I just thought about how how the differentials operate and towing, and I have no idea how a front diff would be effected by towing. Towing actually takes weight off the front end

Not enough weight taken off to prevent damage on dry pavement. A 4WD on dry pavement is usually fairly obvious, howling noise, crow hoping in turns etc. Now if it was in auto 4WD that might be a different story, the OP might want to press the dealer, and I mean really hammer them to prove it was in full time 4WD.

Darksky Enthusiast

Darksky

Posted
Posted

“Crow Hopping” - what a perfect explanatory term. 

 

OP best of luck with this. IIRC there have been a few cases of the transfer case being unknowingly engaged. I agree that a review of any/all updates your truck has had is in order.  You should have easily felt the difference if it was engaged while driving on dry pavement.

 

How or what is the dealer using to  determine that you were towing in 4WD?  What were you doing when it failed? What else can you add to your description of events?

truckguy82 Senior Enthusiast

truckguy82

Posted
Posted
2 hours ago, garagerog said:

Not enough weight taken off to prevent damage on dry pavement. A 4WD on dry pavement is usually fairly obvious, howling noise, crow hoping in turns etc. Now if it was in auto 4WD that might be a different story, the OP might want to press the dealer, and I mean really hammer them to prove it was in full time 4WD.

Yeah I know

 

my point was the dealer said the cause was towing in 4wd, but towing in 4wd puts no more stress on the front diff than not towing in 4wd, it actually puts less stress on it

ftwhite Enthusiast

ftwhite

Posted
Posted

4x4 hi or low on dry pavement with a heavy load would be very hard in a locked diff. Especially under deceleration and turning. I don't see how it would be less unless it was hard acceleration.
Straight line, no turning, or awd/full time 4x4, no way towing causes issues. It protected by a clutch.

Sent from my SM-G960U using Tapatalk

Cathy Wankel New Member

Cathy Wankel

Posted
  • Author
Posted

Thank you everyone for your comments.  I made it back home and took the truck to our hometown dealer and they can't find anything wrong with the front differential.  The previous dealer changed the diff fluid and my dealer said something filings should show up in the new fluid if there was a problem.  Can't believe the other dealer wanted to change me $5000 for a rebuild and there was nothing wrong.

 

Darksky Enthusiast

Darksky

Posted
Posted

Wait, so it went from the diff is “blown”. As in no 4WD - the front drive not functioning, to we had them change the fluid and drove it to a hometown dealer and now it’s fine?

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted

He's explaining what dealer #1 told him...which is seems he did not buy into. Had them change the fluid. Smart. Drove it to somebody he trusted who found it to be fine. His initial reaction in the opening post wouldn't be any more unusual than that of a person being told they have cancer when they don't. An expression of shock and disbelief he shared. No need to embarrass or belittle the fellow. He's still in disbelief over the untrustworthiness of a 'dealer' and shared that too. That act, would it incense a fellow of low moral character? Not likely. Brave man to tell you so much about himself, IMHO. To open up in a tank of sharks. :rolleyes: 

truckguy82 Senior Enthusiast

truckguy82

Posted
Posted
9 hours ago, ftwhite said:

4x4 hi or low on dry pavement with a heavy load would be very hard in a locked diff. Especially under deceleration and turning. I don't see how it would be less unless it was hard acceleration.
Straight line, no turning, or awd/full time 4x4, no way towing causes issues. It protected by a clutch.

Sent from my SM-G960U using Tapatalk
 

Yes, it would be a heavy load on the diffs, but not the front one because of turning locked in 4wd. All the towing does is make it easier for the front tires to scrub.

Bikemobile Enthusiast

Bikemobile

Posted
Posted

What symptoms made you take it in to the first dealer? A dealer that unscrupulous should be publicly shamed if true. 

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