UnstableAviator

I'm out of ideas. No clue.

1984 Camaro, LS1/T56, Moser Ford 9".

- Rear was mostly quiet with my old standard SBC/T56 combo. Just a slight whine at 50mph.

Last winter, total rebuild of the car. LS swap, T56, etc.

- Welded on LCARBS.
- Switched to "Right Stuff" brand disk brakes.
- New Founders performance poly LCA's
- Spohn poly Panhard bar
- 1LE Sway bar, poly bushing

Rear whine was unbearable right away, despite being quiet in the car before the LS swap.

-Rebuilt the 9" center section, new gears/posi refresh.
- Set up by reputable shop in Columbus

Whine so loud it was like a tornado siren inside the car.

- Swapped in a spare T56 in an effort to troubleshoot, no change.

- Borrowed and swapped in a 3.73 pumpkin, known to be quiet from another car. NO CHANGE.

I don't get it, so I ask for help. If it turns in the driveline, its been changed. Axle bearings and driveshaft are the only two things I havn't swapped out, but since the sound is occuring under slight load (pinion depth?) and is a loud whine I don't think its an axle bearing. Plus, I've carefully inspected the bearings, they look and act brand new. I've taken the console out of the car, watched the driveshaft yoke depth under normal driving, the driveshaft length is perfect.

I just can't believe after a center section rebuild, an ENTIRE SWAP of the pumpkin, and a thorough check of everything, the sound is 100% UNCHANGED. Someday I'd like to drive the car without earplugs..

//<86TA>\\

iTrader: (15)

is it the rear or is it the trans?

UnstableAviator

Definately the rear. No doubt about that

UnstableAviator

Found the problem today, and it was totally unexpected. The disc brake conversion is the culprit.

I swapped back the 4.11 gears after pressing on new axle bearings, first run with the car jacked up, sans brakes, was dead silent. Quiest as a church mouse. Installed rotors and calipers, awful whine returned.

Still no solution, but the whine is greatly reduced after putting some copper RTV on the caliper contact area of the pads. I think I've got a resonance with the brackets holding the calipers in place. I used a C-clamp to spread the pads, of course no noise due to no contact. First touch of the brake pedal (while on jackstands) and the hideous whine returned.

UnstableAviator

I was wrong. The whine returned even on a brand new set of 4.30's.

This time, however, I did find the actual problem. The driver side axle was too long. Putting pressure on the diff and making tons of metal trashing the bearings. I cut down a new set of axles, installed a new diff, hit the Power Tour, and its now dead silent after 2000 miles. I just figured I'd update this thread for completeness and incase someone stumbled across it when searching.

Bottom line, axle too long, bad things happen. And by too long, I'm only talking 2mm or so.