2008 2500HD, 6.0L, Rear diff acting up

dirtfan21 · March 14, 2014

I have noticed over the winter that the rear diff was not engaging as it should. When one tire breaks traction it spins for quite sometime before the limited slip kicks in, then when it does it SLAMS into engagement. Should I start by changing the fluid and see if that takes care of the issue? The truck has 87K on it and I'm the second owner. I planned on doing front and rear diff fluids at 100K, already have done trans and transfer case.

Have any of you ever had this type of issue with their limited slip? I don't go out and do smokey burnouts with this thing or beat on it, but I can't say the guy before me didn't. There is no grinding or gear hum noise while driving or once engaged.

Silverado4x4 · March 14, 2014

A locker will not engage if the wheel speed is higher then 20mph (the spinning wheel) this prevents damage now if you were a little below that speed and it engaged then you will feel and hear a bang which is not good all the time. It is best to keep wheel speed low till the locker engages as it see's there is a 100 rpm difference between left and right and will engage the locker.

A lot of people think there locker is broke because they spin the wheel way high and think its broke and don't work.

At that mileage it wouldn't hurt to change the fluid.

dirtfan21 · March 14, 2014

I appreciate your response, I should have been a bit more clear though with my question. I am aware how the limited slip works and should have explained that this occurs at low speeds. Like this morning for instance, I had to back up into a snow drift and was in 2WD. I was under 10 MPH and gradually gave it gas to purposely test the engagement of the limited slip. I would estimate the right rear tire spun in place for approximately 5 seconds before the drivers side wheel engaged and when it did it slammed into engagement. This is the fifth GM truck with the limited slip I have owned so I am pretty versed in the feel, sound, and engagement of the locker. I have never experienced this before, usually the engagement is pretty seamless and quick. I suppose I'll start with changing the fluid and go from there.

ATMINF · March 14, 2014

Not trying to sound like a smart butt, the g80 is a locking Differental in the 14 bolt, not a limited slip. If your experienced with the 1/2 ton trucks, those are different. I would also say it would be good to swap out the rear fluid, remember in the 14 bolt they do NOT need the limited slip additive, only a good rear end oil. I used full syn Moblie 1.

GMCustomerService · March 15, 2014

Hey there dirtfan21,

I understand that you are looking for technical advice. As a customer service representative, I'm not able to provide much in the way of do-it-yourself information, so I'm glad to see forum members are beginning to step in with feedback. If you have any lingering concerns feel free to contact me by private message.

Jennifer T.

GM Customer Care

Silverado4x4 · March 15, 2014

Not trying to sound like a smart butt, the g80 is a locking Differental in the 14 bolt, not a limited slip. If your experienced with the 1/2 ton trucks, those are different. I would also say it would be good to swap out the rear fluid, remember in the 14 bolt they do NOT need the limited slip additive, only a good rear end oil. I used full syn Moblie 1.

HUH? The G80 is a G80 and works the same whether its in a 1/2 ton or 3/4 ton only difference is the 3/4 ton is bigger.

ATMINF · March 15, 2014

True a locking diff is a locking diff, but the locker in the 14 bolt is "louder" and more "pronounced", than what I have seen in the 1/2ton ten bolt rears. Also a lot of people mistake the limited slip in the 1/2 tons thinking they had lockers. Hope that makes sense.

dirtfan21 · March 15, 2014

Not sounding like a smart butt at all, this is my first HD and my others have been half tons. I apologize if my word usage is not correct, but I think you guys have gotten my drift. I just thought it was odd that it is taking so long to engage, unlike what I have experienced in the past. I'll change the fluid and report back as it seems that is the common consensus. Hopefully that is all it is...

NEFisher11 · March 18, 2014

True a locking diff is a locking diff, but the locker in the 14 bolt is "louder" and more "pronounced", than what I have seen in the 1/2ton ten bolt rears. Also a lot of people mistake the limited slip in the 1/2 tons thinking they had lockers. Hope that makes sense.

In the 1/2 ton trucks it is a locker not a limited slip. I have the G80 and can feel and hear it when it engages.

ATMINF · March 18, 2014

Yes the 1/2tons also have a locking Diff option, but a lot of people mistake their limited slip rears with locking diff in the 1/2ton trucks. The 14 bolt 3/4ton trucks diff is a much more pronounced locking diff.

scooby5121 · March 19, 2014

I feel and hear mine very pronounced every time i leave my driveway in the summer.... Having said that , yes my road in front of my house has nice black tire marks in front all year long...

Loud and Noisy, it has been great with over 140,000 klm with no problems.

Scooby

In my Bio.. 3500 sieries

sdeeter19555 · March 19, 2014

Just changing the fluid can make a difference in the feel of the G80...

Based on the flavor of the month, I opted for Amsoil Severe Gear early on because, well, everybody else did and everybody said it worked great. I can tell the differential takes longer to engage, it has a completely different feel. I also get a lot more single wheel action than I did before the fluid change...

Knowing what I know now...I might have opted for Royal Purple (had good luck with it before) or the OE fluid.

dirtfan21 · March 21, 2014

Now that the weather has warmed up some, above freezing temps, I have noticed the G80 is working a lot better recently. I as dumb as it sounds I didn't even think that this horribly cold and snowy winter may have affected how it reacts as well. I'm still planning on doing a fluid change but I feel a bit better about the internals as of lately. My guess would be the fluid is old and maybe in the frigid temps it affected the engagement.

cliobogger · March 22, 2014

Just changing the fluid can make a difference in the feel of the G80...

Based on the flavor of the month, I opted for Amsoil Severe Gear early on because, well, everybody else did and everybody said it worked great. I can tell the differential takes longer to engage, it has a completely different feel. I also get a lot more single wheel action than I did before the fluid change...

Knowing what I know now...I might have opted for Royal Purple (had good luck with it before) or the OE fluid.

Don't say that, I have 6 quarts of it sitting in my garage waiting to go into my 03 HD...