Rear differential lock

Josh Tonn · March 31, 2020

I purchased a new 2018 Silverado 1500 LT less than a year ago. It had 55 miles on it when I drove it off the lot in April of '19. It just clicked 14K and I am well within my warranty period. Recently, while making left turns, at low speed, such as parking lots and turning corners the rear wheels lock. It locks enough to drag the wheels and I chirp the tires as I corner. It sounds like the rear differential is grinding as I power through the turn. It as if the 4WD engages or the posi locks. I have the auto 4WD option, however, it is always in 2WD when this happens. As soon as I straighten out or make a right turn it goes away/unlocks. The dealership cannot find anything wrong. What gives??

diyer2 · March 31, 2020

My guess.

Do you have the G80 rear end?

Has the rear diff ever been serviced?

Might be the wrong gear lube was put in the rear end.

No modifiers in the gear lube are required for the G80.

Check out this thread.

Josh Tonn · March 31, 2020

16 minutes ago, diyer2 said:

My guess.

Do you have the G80 rear end?

Has the rear diff ever been serviced?

Might be the wrong gear lube was put in the rear end.

No modifiers in the gear lube are required for the G80.

Check out this thread.

I have no knowledge of any differential service. I purchased the truck with 50 miles on the odometer in April of '19. It just clicked 14K. Well within its warranty and only routine oil changes and tire rotates. This is frustrating for a brand new truck.

truckguy82 · March 31, 2020

49 minutes ago, Josh Tonn said:

I purchased a new 2018 Silverado 1500 LT less than a year ago. It had 55 miles on it when I drove it off the lot in April of '19. It just clicked 14K and I am well within my warranty period. Recently, while making left turns, at low speed, such as parking lots and turning corners the rear wheels lock. It locks enough to drag the wheels and I chirp the tires as I corner. It sounds like the rear differential is grinding as I power through the turn. It as if the 4WD engages or the posi locks. I have the auto 4WD option, however, it is always in 2WD when this happens. As soon as I straighten out or make a right turn it goes away/unlocks. The dealership cannot find anything wrong. What gives??

Do you mean the dealership can’t duplicate the problem?

Also are you saying it doesn’t happen when you’re in auto 4wd?

Is it only turning left?

tyler.frost92 · March 31, 2020

G80 could be stuck locked. Shut off traction control, mat it in reverse enough to chirp the tires. See if it's unlocked after switching back to drive. Either way the dealer should have fixed it.

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tyler.frost92 · March 31, 2020

G80 could be stuck locked. Shut off traction control, mat it in reverse enough to chirp the tires. See if it's unlocked after switching back to drive. Either way the dealer should have fixed it.

Sent from my iPad using Tapatalk Pro

tyler.frost92 · March 31, 2020

G80 could be stuck locked. Shut off traction control, mat it in reverse enough to chirp the tires. See if it's unlocked after switching back to drive. Either way the dealer should have fixed it.

Sent from my iPad using Tapatalk Pro

flyingfool · March 31, 2020

open it up, and check the gov weights, see if they are moving freely or stuck wide open

Z45 · March 31, 2020

Could be normal as they will act that way sometimes. Older service info but still applicable.

Quote

Condition/Concern:
Customers may comment on a chatter or shudder from the rear axle on vehicles equipped with an Eaton locking differential. This condition would be noticed in parking lot maneuvers, turning, or during locking differential engagement and may be more noticeable when the differential is hot. Locking differential clutch chatter may be causing this concern.

If differential clutch chatter is encountered in a vehicle equipped with an Eaton locking differential, flush, drain and refill the differential with new synthetic fluid.
Important: Installing any friction modifier causes the clutch pack in the locking differential to slip and miss engagement. A fluid flush can often remove debris that is a contributor to clutch chatter. Adding friction modifier additive can cause a loss of locking differential functionality

Mass production and cost concerns lead to "good enough" (low bid supplier) but not necessarily the best available. Look at OEM tires, for example, decent quality, "good enough" quality, but not necessarily the best available. The same could be said for shocks, brake pads, oil and filters.