Question for the truck guys

[rowerybo]

Have a 2012. Silverado 1500 LTZ with the locking rear differential, 2wd. The locking rear has been verified on the build sheet.

We tow a 22ft boat quite frequently and feel as though the rear differential is not locking when we slip on the ramps at low tide. Took the truck to the dealer and they performed the test of spinning the tires in opposite directions, the tires locked.

Get back to the ramps and the truck slips for the second time, right tire spins and the left tire does not kick in.
We have tried M1 and regular drive.

We had an 04 silverado prior to this and you could feel the locking differential engage and the truck would pull right out.

Anyone have any ideas what may be causing the issues?

[christianmotox]

Maybe is a Limited slip differential. Locking differentials will have some sort of button you need to engage at some point.

Limited slip diff and Locking diff are 2 different things

If you have limited slip Diff, well, it will slip at some point.

[Silverlsinva]

im pretty sure the silverados the newer gen never offered a limited slip only locking, how do you know the one wheel is spinning and the other is not spinning? did you witness the dealer do the test or is that what they told you?

[Applegarth]

How much do you let the tire spin? My 2011 Silverado takes a little while to lock when I spin the tires. It seems that my traction control catches the errant wheel before the locker (from a stop that is).

[rowerybo]

2 or 3 revolutions before stopping and trying again.
Did not witness the dealer do the test but they have had amazing customer service with us for the past 3 trucks.

[Jason P]

Older trucks had a percentage of how much one tire would spin before the other would engage. So if you were driving on dry asphalt and making a corner the rear end wouldn't bind up. Jack the rear of the truck up put it in neutral and spin the tires manually. If they spin the same direction you have a posi of some sort. If one spins part of a rotation before the other starts to spin the same direction you can figure the percentage of the limited slip. If they spin opposite direction, you have an open carrier.

[rayhawk]

The locker they use is known as a gov lock, I assume that is what you have. It takes a certain amount of speed difference between tires to cause it to lock, not a certain amount of rotations. Maybe you need to be a bit more agressive on the throttle to get it to lock up.

[rowerybo]

We'll see what happens this weekend. Thanks for the help.

[2001ragtop]

Rowerybo, I have two 2008 model GM Trucks. On the gearshift stalk on the steering wheel, there is a button there called "towing".

I believe this towing button will only change the way the transmission shifts.

However, you might press that button and then see if it helps in any way. This technically should make no difference but I just thought I would throw it out there.

[05stram]

unless you look in the glove box and find G80 on the sticker in the APOs then you have a limited slip. The new limited slip will give traction to the wheel with the most traction - however sometimes it takes a tap of the brakes to get it to activate correctly.

[MMC]

The Eaton locking differental requires more than 200 RPM's differance between sides for it to lock. They also will not lock at speeds above twenty MPH. G80 is the correct RPO code, in use by GM since the 70's.