I went to Valvoline today to get my oil changed then they said I needed to get my front & rear differential fluid changed and transfer case... so that was like $200 then when I get back home I start to notice once off the highway when I go to make turns my rear tires feel like there no spinning just dragging behind the truck like im on snow and not goin anywhere so my boyfriend got in my truck and slowly drove it and turned and my truck like bounces like defiantly the left rear sticks and dont spin causing my truck to shake and its never ever done that before until I got the fluid changed!! whats wrong with it? what do I do? im taking it back tomorrow but what if they cant fix it? and I deff dont wanna keep driving it if its gonna make my tires like lock up and eventually cause more damage you know??

Make sure you are not in four wheel drive. They may have put it in four wheel drive while changing fluid.

no i stayed in the truck the whole time and it was in 2wd the whole time and tonight when i was looking at it seeing what was wrong i put it in 4wd to see if it did the same thing and it was the same still locking up

Does it have a locking differential?

I dont think so...I drive a 2006 Chevy Silverado 2500HD

I dont think so...I drive a 2006 Chevy Silverado 2500HD

Check the sticker inside your glove box,there will be a bunch of numbers on it.If one of them is G 80 you have a locking diff.

The locking diff. should not engage unless one tire begins spinning faster than the other....I forget what the speed difference has to be between the two tires, but just going slowly in a circle should not engage the locking diff.

The exception to this is that the diff has engaged prior to your test and it won't unlock. Seems like if this was the case you would have noticed it before now. Do you know if the lube-guys took your truck for a "spin" ? :bat:

My thinking is did they put fluid back in it?????

I'm fairly sure all the 4x4 HD trucks come with the G-80 from the factory as standard equipment. I know my 2006 did.

I must say that, from your description, it certainly sounds like the rear locker is locking up prematurely, or has locked and will not unlock. It takes approximately a 100rpm differential between the two tires to initiate the locking mechanism, per a statement I read from Eaton a few years back. In "normal" turning, it should not lock up.

I'd get someone under that truck asap and check to see if they added any fluid. If the fluid is not there, or way low, the mechanism does not get lubed, and might experience high friction loads that would alter it's "normal" operation.

Pull the check/fill plug (the one on the rear of the differential cover, not the one underneath) and stick your finger inside. You should be able to feel fluid at, or just below, the level of the hole. If you feel nothing, curl your finger down inside as deep as you can, and see if you can feel oil. If you still cannot feel oil, go get some and put it in, pronto. Then I'd check the other two fluids (front diff and t-case) as well.

If you're unable or unwilling to do these checks yourself, ask around and find a reputable service facility nearby and have them do it.

I took it back yesterday and I guess they didnt put enough lube stuff in it so now its working fine... I hope it stays that way

Didn't put enough oil in the rear end? Bet they didn't put any in. All these quick lube and oil change places have mimimum wage help and high employee turnover. They don't like to have the customer watch what they are doing. Glad you caught it early on before any damage done. Keep your receipt on this one and make some notes, dates, time, place and who you spoke with just in case.

The "lube stuff" is probably the friction modifier additive.

^^^^^^^That would just make it chatter- not lock up (I wouldn't think anyway....)

The g80 does not require friction modifyer. At least the older ones don't. They probably didn't out any gear oil in. This is why I ne'er trust any quick lube places. I unfortunately worked for one once. And I watched a Co worker blow up a brand new Mercedes. They drained the oil and changed the filter but forgot to add oil before sending the customer off. Needless to say the company wound up buying him a new Mercedes. And the employee in question did not lose his job. Which shoes you his much they a. Mark up the prices and b. Actually care about quality service.

I agree with k9dmax; the lack of FM would probably make the rear clutch chatter, but should not make it lock up. Per Eaton's own statment the lack of FM is not a detrimental thing; just an annoyance.

The problem she described is way past an annoyance; it was likely a lack of lube all together. The frictional drive system can't operate long without the fluid and will quite likely make the clutch/pawl engage.

Glad all is now well. I suspect they didn't put enough fluid in, or any at all. Good you caught it early; probably little harm done.

Don't go back to them.