I have a 2004 Sierra Ext Cab 4x4 with Quadrasteer and I have noticed it seems to be squealing more when I make sharp U-turns. These are very slow speed U-turns on dry asphalt. It still has the factory tires and about 30 K miles. My suspects are the differential, the tires or alignment. Is this normal or a common problem and should I get it checked out? I checked with a guy that has a 2003 2 wheel drive, Sierra Extended cab w/ Quadrasteer and he does not have the problem.

This has usually been attributed to having a good, tight posi unit. If it seems excessive or has increased a substantial amount, you may want to have it looked at.

Thanks,

I will schedule a visit to the dealer.

Not to freak anyone out, but I just dropped my truck off at the dealer for a second time due to it making a groaning noise during tight turns. They changed the fluid the first time I was there. I really did not think that would help, but I thought I would humor everyone (you know the sugar and vinegar attitude). Well I got them to let me take the guy that will be doing the work for a ride. He agreed that the noise warranted a tear down of the rear axle.

As for the posi, what type of posi is used. If it is a helical gear type, I am not positive, but I do not think it should be making any noise.

I had the rumbling noise in my rear axle, took it to Chevy and $185.00 later my rear end is quiet again. Chevy said that they performed a rear axle service - it was a maintenance issue, not a warraty issue, that's why I had to pay.

Ya know, Dave, I've been thinking more and more on that very thing here lately. There's been lots of talk on rearend issues and the posis and the additives that everyone's having to add... helical posis don't need additive And, no, they don't make much noise, either.

But, I KNOW I didn't pull this from my butt . I had asked someone and that was what I was giving. I save EVERYTHING, so I need to go back and find it. The problem is... I save everything, and finding it will be a pita

I've almost been tempted to drop my cover (tell MrsQ I'm doing a fluid change )just so I could look at mine... but of course, it's just not quite that simple with ours, is it


I'll research and get the definitive answer.


I thought I had. And I guess, really I still do, I'm just kinda confused


I wanna see one.

Well the dealer had me pickup....my pickup? At any rate they gave me some paper from an internet site about some tests that they performed. They said that these tests confirmed everything was working as intended. So needless to say my truck still groans and I have a case number that is supposedly going to cover me if there is a catastrophic failure of the rear end (that sounds kinda messed up)

Being as I have always serviced my own vehicles and have always gotten the results I desire, I am seriously thinking about tearing into this thing myself. I guess the deciding factor will be exactly what kind of posi resides in that Dana 60.

I have heard a couple of stories about this subject. Most do not have solutions. One guy spoke of replacing bearings, the other said he had his diff rebuilt.

Here is my take. If my dealer and GM are telling the truth, the guy who had his bearings changed also had his fluid changed and the tech got lucky and added the right amount of gear oil and additive that quieted the truck, THe guy that had his posi rebuilt probably received a good solution to his problem if these posi's have clutches. Brand new clutches and lube would probably solve most any noise.

SS crew what was involved with your rear end service? Did it fix your problem permanently?

All I know is that the rear end is quiet now. The stealership charged me $185 for a rear end service. For $185 they better have gone in there and polished each gear to mirror-like shine. I really don't know what was included with the service procedure, but it better be more than just draining the fluid and replacing it with fresh stuff.

As far as a permanent fix, it sounds like this is a maintenance issue. But why is happening? Is the rear end lube a non-heavy duty grade? Usually you can go forever on the factory filled rear end. I went about 100k on my last truck with a locking diff without any problems. The dealer asked me how often I had the rear end serviced because everything still looked new.

It looks like we need to change the rear end fluid every 35,000 - 45,000 miles to keep things quiet and properly lubed, but come on, $185, that's a little steep. How difficult is it to this task? (I haven't looked, maybe it is harder than I think).

I'm at 27k miles and never touched mine. Of course, when the hunny had that accident a few months back, it got new juice, but I never had any noise before or since.

As far as a fluid swap goes, it should be pretty easy- plug at the very bottom, plug on the side. $185 is steep, but we all also know the dealer wants like, what- $45 a quart for the QS-specific fluid. What kind of scam is that


It's bugging the heck out of me now, not being sure exactly what posi in there. There's just too many things that don't add up for them to be the TrueTracs that I was led to believe, that I in turn led all of y'all to believe

I WILL get to the bottom of it


And I agree with you, Crew, rearends should last the life of the vehicle, practically, with a minimum of attention. Why do ours seem so high-maintenance. I mean, the rearend itself is just a rearend- the internal workings are just like any other.....

Hey guys, I got to see inside the differential when they had mine opened up. These rearends have a clutch pack. The disks look alot like the ones in an automatic transmition. If you use the specific GM oil for the Q steer, you don't have to add the modifyer. Otherwise you need the modifyer with any synthetic oil you use.
I also thought it was interesting that the axel bearings are actually part of the axel. This means that if a bearing goes bad, you have to replace the axel too, about $700 for that part.
There's also a special GM tool required to pull the axel. It's amazing how many dealers don't have that tool. I guess it's a good thing, because they have not needed the tool up until they worked on my truck.
Anyway, if you figure 3 or 4 quarts of the GM oil @ $35 per quart, thats only $40 to $60 labor to service the rearend. Not that bad for a dealer.
If you do it yourself, I quess you need to add a little extra friction modifyer to quiet it down some more.

Well, that settles that.

I'm gonna find out where I first heard that truetrac info

That's some interesting info on the axles. I wonder why the heck they did it like that ?? Maybe we can get KL in here

Well I rode in my buddy's 2003 SD. That thing operates like butter. No noise what so ever, and it has never had noise. I changed my fluid. I used Lucas synthetic gear oil and a bottle and a half of friction modifier. I realize that GL-5 synthetics should not need the modifier, but I figure I would try some overkill. The noise is better, but not gone, and now there is a new noise that seems to accompany a tight turn. As I drive off in a straight line I can hear something rubbing at about the same speed as the rear axle is turning. WHen they changed the fluid at the dealer they stated in the service reciept that the fluid was extremely dirty. That leads me to believe contamination from either 1. the clutches coming apart 2. a bearing going south. I am going to a new dealer to try my luck a second time.

Awphil03 thanks for the info. I cannot seem to find anything on the G86 axle. BTW I showed the paper work I received from the dealer to my buddy. It was supposedly the test procedure given to them by GM, well he pointed out something I missed. The test procedure was for a G80 Rearend!!!!

I really do not understand the dealer's problem with tearing down this rear axle and getting to the bottom of this for me?

Well I talked to a GMC representive, in customer service. They were about as helpfull as a rabid wolverine chewing on my head. I sent an email stating the problem I had with my truck and how I had received no solution from the dealer and no recourse for a solution. The representative then proceeded to ask what he could do for me. I kindly told him I would like my truck fixed. He the put me on hold and called the dealer. When he ruturned he told me that the dealer explained to him that, they had spoken to GM and was told that was normal, then they drove a similar truck that made the same noise. I assured him that the noise was not normal, and that worn out fluid was not normal, and that I had driven, not only a similar truck, but the same year and model, and it did not make the noise. He then decided to check for TSB's, which he said turned up nothing, that in turn did not jive with the dealer paperwork I received, about the whole test procedure presumably performed on my truck. He then asked if he could refer me to another dealer. I then thanked him for his time and hung up. It was in my opinion a worthless 15 minutes. I contacted GMC for there technical knowledge and they inturn called the dealer that gave me the run around to aquire their information.

At any rate the good news is that the Lucas gear oil and GM additive seem to be working. the truck has been quite for two days. So either the posi quit working or things are getting back to normal under there

I'm new here but have found you through another forum. I have a 2002 Sierra Denali and have had the groaning/grinding noise in my rear axle.

The first time I took it to the dealer and they tore down the rear axle to find all the bearings and clutchpack were about to explode. They ended up replacing the entire axle under warranty. In addition, I had a slight jitter in the rear steering so they replaced the steering unit also.

2500 miles later it's doing it again. It's now in the shop and the dealer said that there are metal shavings in the axle housing and the axle needs to be replaced. They claim that they can't repair the existing axle because there are certain parts that aren't available - the only option according to them is to replace the entire rear axle again. I'm getting tired of this and it sounds like this is becoming a more prominant issue among QS owners.

Thankfully I bought an extended warranty. For those that are having this problem you can plan on a $8000 repair bill if you have to replace the axle and steering unit. A new axle is $5500, the steering unit is around $1200, and the rest is labor.

Oh, one other thing... Make sure you add the friction additive when you service the axle. The dealer forgot to do that when they replaced the axle the first time and that may be why it's so noisy again. It doesn't explain the metal shavings though.