Clicking from rear under initial load...
 

When initially rolling from a stop, forward or reverse, I notice a clicking/popping noise which appears to come from the rear of the car. I looked underneath the vehicle at the U-joints, drive shaft, etc. - all appears tight and very clean. Also, a check of wheel bearing play, results in none for the driver's side rear, and a small amount in the passenger side rear. The car has 19k miles on it, and was not driven but 1600 miles in the last 11 years.

Once you get rolling more than a few mph, the Z runs smooth and quiet as as if on rails.

I found this post in the C-4 section, and it sounds very similar to my issue... claiming it's rust on the spindle shafts.

Anyone had this issue or have other thoughts?

Re: Clicking from rear under initial load...
 

yup, add new washers and torque the spindle nut to 164 #-ft. Make that 190 instead of 164. 164 is the torque specified in the C4 service manuals, but apparently there was a service bulletin changing the value to 190 #-ft after there were field complaints.

Re: Clicking from rear under initial load...
 

additionally the pop is coming from dry axle stub splines. grease the splines and retorque the axle nut- no need to pull the half shaft. just remove axle nut and work grease in with a small brush on both sides- then thrust the axle back and forth until it is well greased. retighten nut to spec. I have never had to get a new teflon coated washer, but it is recommended.

Re: Clicking from rear under initial load...
 

Thank you very much, Gents. Mike100 - I didn't think about a shortcut to fully removing the wheel bearing to get to the spline. I'll give your recommendation a shot.

I did find this descent C-4 wheel bearing removal video if I do need to go all the way with it. But hopefully not…

:cheers:
G

Re: Clicking from rear under initial load...
 

You won't have to unless you are servicing the wheel bearing or repairing the halfshaft. The c6 has the same issue- all the vettes do it. you can get about 3" of movement on the axle once you remove the nut. Grab it from behind the wheel or push the center of the axle stub with a punch or something that won't mar the threads. I don't think I even had to remove the tire...just jack up the rear of the car and jump down in there with a brush or a stick and jam a little grease on the exposed splines. This is a 10 min job.

Re: Clicking from rear under initial load...
 

I had a similar issue, but it turned out I needed to replace the driveshaft U joints. Mine were tight, but once the shaft was out you could tell they were very dry and crusty.

Re: Clicking from rear under initial load...
 

Going to give this a try in a couple of days when I have a little more time. Thanks for the tips.

G.

Re: Clicking from rear under initial load...
 

I would recommend 190 ft lbs. If I remember correct, GM revised torque for manual C4 rears to 190.

Re: Clicking from rear under initial load...
 

You got me there - I thought 164 was the corrected value. Use 190 folks.

Re: Clicking from rear under initial load...
 

I finally got around to working on this. I ended up doing a complete job by removing the Wheel Hub & Bearing on both L & R sides. To get a Hub off, it required various extension lengths pieced together with the T55 Torx. I found that on the top torx hub bolt, a wobble extension allowed a workable angle for the impact wrench.

The spline on both L & R sides required wire brushing clean of rust, as did the inner spline grooves on the Wheel Hub & Bearing.

I did a lot of brushing and cleaning of all parts in and around the entire area… just for the fun of it.;) After lubing with Mobile 1 Synthetic bearing lube the Spline, Teflon Washer, and the inner spline grooves on the Bearing Hub, I reassembled. Torqued all bolts to specs.

Two drives, and clicking is gone. Thanks to ALL for the direction to go on this.