Rear Wheels Locking Up On Turns

[eatnupbyatornadr]

2014 Silverado LT 1500 4x4.

 

So i was coming back to work today and i chirped the wheels in the driveway as usual... Then I noticed something funny as I pulled into one of the stalls. As I made the sharp left to swing into the spot I felt like my truck's 4x4 was engaged. I say that because I had to press harder on the gas pedal and it felt like the rear tires weren't pushing the truck. It was reminiscent of being on the trail and hearing the engine push harder to get the tires going. In any case, I pulled in with the rear left wheel hopping and semi dragging. I was going no more than 5mph BTW. So i straightened the wheel and backed straight out. The truck moved just fine. As I turned the wheel to swing the front end left in reverse I could hear the rear left wheel "hop" on the asphalt/rocks. I stopped and turned the traction control on/off. I then pulled forward a little in a turn and same symptoms. I then turned the 4x4 from 2wd to 4 hi and then back to 2wd. After each engaged I started turning right to go down the driveway with the wheel still hop/dragging. So I deliberately hit a bump to see how it would act. As the crest of the bump i heard a LOUD pop. After that I could turn the truck sharply and the rear wheels wouldn't bind. It was back to normal. Any thoughts?

[Ltz73]

My truck did the exact same thing two weeks ago. I spun the wheels in the rain leaving a red light. After that when I turned hard left into the driveway the rear was locked up. Felt like the posi locked when I spun and never released. When I backed out of the driveway it was still doing it. By the next turn it had released and all was well. I had the dealership look into it, they said everything checked out. I just wanted to make sure I had it noted by them in case I have problems further down the road when the warranty runs out..

[Badass69]

The good old Gov Lock locked up and wouldn't release. Eatons revolutionary design that has been exactly the same since it was released 42 years ago in 1973 lol. It's not good if the lock plate is binding in there somehow to the point the flyweight isn't disengaging it. If it released though unless something broke the dealership won't find anything and will just send you on your merry way.

[eatnupbyatornadr]

Well I agree on both of your stealership comments... And both of you just confirmed my thoughts on the posi. I've never had any rear drive vehicle lock up before so its just the oddest thing. I figure there might have been some secret someone knows about to keep that rear diff free I.e. maintenance, switch out the existing fluid and use a different brand of fluid, keep my foot out of the throttle lol etc.. Some simple solutions I guess is what I was after. Thanks for the comments thus far

[Badass69]

A good synthetic oil is all a gov lock requires. The locking action although using friction discs as a damper is purely mechanical so it doesn't need anything crazy. Don't use a friction modifier if you do change the oil... just use straight synthetic gear lube. The lock plate locks the spider gear to the carrier and a flyweight keeps it engaged and then disengages it above the set speed of around 25 mph. It's a simple design so there really are no tricks for it per say.

 

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[pm26]

Sometimes stopping and moving the vehicle in opposite direction helps unlock the differential. That's what I did when I accidentally locked up my differential spinning rear tires on the wet lawn and then taking a hard right turn onto the street.

[redwngr]

How the G80 locker works:

 

 

[Rawyzf]

Good info here, just had this happen. Love the search functionality.

 

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[Dnt]

Centrifugal force will disengage it just speed up above 25mph. Mine does that out on the farm in the mud quite a bit, it is a bit disconcerting the first time it happens just a quirky little thing, you will gte used to it. Your dealer will tell you......................wait wait wait for it........ it is Normal

[KBoy420]

So what is the actual fix?  Got some snow yesterday, and have a long gravel drive.  Used auto-4 and 4-high yesterday.  Turn it back to 2wd before I shut it off (gave it 30 sec to ensure transfer was complete).  Parked over night.  Went out this morning, on clesr pavement rear locked up on several 90 degree turns making a hell of a noise.  Just take turns faster?? Lol

[300 Blackout]

Not sure how many miles are on the truck but if it just started doing this, a good place to start is changing the diff fluid. It certainly can wear out and lose its lubricating properties. I would do that first before going any further and see if it fixes the issue.

If it doesn’t resolve after that I think you may be due for some differential service to see why it’s binding and/or replace some parts.

Amsoil Sever Gear 75W-90 is what I just put in mine after I replaced my ring, pinion and bearings but I left my auto locker stock. No issues whatsoever. 72,000 miles.

[KBoy420]

Thanks.  Its a 2016 with 41k miles.  I called GMC today and found out it actually is still under warranty - power train till 60k/5 yrs.  So guess ill just take it in...

[Gofas]

My Silverados rear ended binding on driveway turns. With creaky rear brake noises. Maybe brakes locking up, rather than rear ended?

 

[BruceT]

My 2019 Sierra 1500 does the same thing. Last night, for the 2nd time, left rear tire was on pavement while the right rear was in the snow. Tried to make a u-turn. Rear and locked up. Every turn made going home was a fight. All at 30mph or less. Backing into my parking spot was also a fight. Is something about to totally brake? Is it going to fail completely on a trip from NY to NC? What's the correct fix for this problem before it becomes a major issue? Bruce