Am kind of concerned its the diff or trans. It only happens sometimes and at very low speeds (just moving) as soon as I speed up it seems to stop. Pretty sure its coming from the rare.

It's like a popping sound only when moving.

 

could be one of these, brakes, u joint, rear center section gears or bearing, axle bearing, carrier bearing if you have two piece driveshaft. is the car jumping when it pops?

 

Also, is this coming up as soon as you start the car, or after driving for a while?

 

Does this happen when you rotate the steering wheel? Mine does and I'm wondering if its the same problem as yours.

 

It seems to only happen after a while of driving, not on cold start. It possibly happens when rotating the steering wheel, but only slightly, and then seems to continue when straigtening up the wheel. I don't think the car is jumping, but possibly like its struggling a little bit?

It has quite a metalic sound. I'm trying to get a vid of the sound, but its only happening sometimes so hard to predict when it will happen.

Also, my brakes are pretty poor at the moment. the brake pedal doesn't have much travel, but I have to apply a lot of pressure to slow the car down. Been meaning to get this fixed! Same with the hand brake. I was wondering if the brakes were sticking but don't think it would make that kind of noise.

 

Get it checked and have them open up the rear differential while the car is on the lift. If anything, at least have them change the fluid. It's one of the most overlooked areas in the vehicle for fluid changes. I had the same issue where the sound would only come up after driving for a while and it turned out to be the rear differential fluid, and the lack of Posi additive. If anything, at least you'll have the new fluid with posi additive to rule out!

 

if your brakes have worn down the pad all the way then its hitting metal. have a look at the rotors and if there all grooved and uneven then you need a brake job asap. car is not safe with brakes on metal.

 

Thanks for your responses.

Not really the answer I wanted, but i'll take it in later this week and get the dif oil changed and inspected. Only thing is I have to try and track down that posi additive. Can someone give me the exact name? Not sure it will be easy to find where I'm from.

I have no service history for it (aside from an oil and fuel filter change just before I got it), so I should really get the trans serviced as well. It's not my dd so its just parked in the garage atm.

Has 60,000 miles on it, surely posi isn't on its way out already

 

Even still, it's good to get it checked. You shouldn't have to look for the posi additive, the shop should have some (If they know what they're doing, that is). Good idea getting the transmission checked out as well, this way you can start keeping track of your own service history

 

GM Limited-Slip "Posi" Additive