: Noise Diagnostic Help Please

soon to V
10-11-08, 05:00 PM
This forum's been great for me to always find out issues before going to dealer, thanks; now a question after searching noise threads to little avail. Issue is twofold. First is clicking sound coming from somewhere in rear axle area. Click happens at drivetrain engagement and every shift. Second is rubbing/grinding noise when turning but only after warmup (15 minutes of driving).

1. Click. This sound most of the time seems to be coming right off the left rear wheel, best heard when engaging next to a building as the sound reflects off. Sometimes though it comes off the right side rear axle/wheel area. Sounds like metal on metal. Not sure if its differential related or CV joint related or other. Note that I have had front rear diff bushing changed about 5k ago and no noises after that until now. This noise is not a clunk.

2. Grinding/Rubbing. I thought this was the fluid issue not getting to the diff clutch packs since this only happens after turning, but after changing the fluid 4 times over car life, twice recently by the dealer (since they wanted to make sure they did it correctly), I'm thinking it has to be something else. Note this is an 04 with 55k miles and original diff. I have driven car such to protect diff but realize I would probably be replacing it some day. If that day is now, fine, but I want to make sure I going after the right problem first. The car is still drivable, but makes these nasty noises that need to be addressed. I've parked the car until I diagnose and have fixed.

Last question: If this is diff, do I try to repair first or simply drop in the 06?

Responses appreciated!

10-11-08, 06:30 PM
If you need a differential you will want the new (2006-2007) unit. The older version (2004-2005) experienced catastrophic failure (the cases grenaded) whereas the later version does not. There are no older units in the GM parts inventory. If it is making noise the gear set is likely beyond repair and it would not be a good idea to put a new gear set in the obsolete case.

10-11-08, 08:40 PM
Not real sure what that click is, but might be related to the diff.

If that grinding occurs while turning in a parking lot situation, then is most likely your diff. Get a new one either through your warranty, by buying one, or by stealing one ... just get one.

10-12-08, 10:28 AM
They may have forgot to put in the limited slip additive at the dealership. Happened to me and a few others. That would explain the rubbing noise after and during a turn. I don't know what the clicking sound is. My guess would be a cv joint.

10-12-08, 03:36 PM
I would first buy a bottle of limited slip additive from the dealer and put it in. Drive it for a couple days and see if the grinding noise stops.v I agree with Jayrcr3 that it's probably the fluid.

soon to V
10-12-08, 05:53 PM
Thanks for input guys. Just as an FYI, when I questioned the service manager if the additive was put in, he just went ahead and changed everything again at his cost to make sure and he confirmed they put the additive in, so although stranger things can happen, I think its pretty safe to assume the additive is in and its something else. I should also note that there is no grinding noise when driving straight at any speed, and the grinding noise happens in both forward and reverse (turning - even if only slightly turning). Will take it in tomorrow and see what gives.

10-12-08, 06:59 PM
It has to be the clutch packs in the rear diff. If you have to get a new diff make sure you get the one Ewill was talking about in a post a couple of days ago. He said they started getting them the beginning of this year, and they seem to be holding up really well. You may have to PM him for the part #.