The following is an email I sent to Moser. Any of you driveline gurus out there know what this problem could be ?

I purchased from Moser a 9" Ford housing, axles, ring gear & Trac Loc differential for my 1987 Camaro. I have been working through several problems with the installation, which include,
Drive line vibration @ 65 mph - fixed, was driveline angle at trans.
Right side axle pushing the bearing apart - fixed, shortened axle (at your suggestion) & used a Napa wheel bearing ( A press ring from a Green bearing must be used to clear the axle seal, I found this out the hard way.)
The third & most perplexing problem, that has not been solved, is a loud whine under load at speeds above 25 mph. When you let off the gas & coast it is quiet, as soon as throttle is applied noise immediately returns. The first thing that came to mind is the ring gear pattern. I took the third member out I checked the pattern & found it to be okay. The problem persisted. I took it out again & had a machinist that does rears check it & he found it okay. I have since changed both u joints & rechecked drive line angles, with no change. I am out of ideas. Can you suggest any areas to look at ? The third member came from a junkyard & has had the ring gear & all the bearings, replaced except the pinion pilot bearing, could that create such a noise ? This problem was not present until a month after the installation. The noise is very loud & seems to come from the rear & resonate in the steel drive shaft.

Thank you in advance,

Rick Franklin

 

richmond gear set? they tend to make a good bit of noise

 

US Gear. I've been down the path with Richmond before & won't use them on the street for that reason. These gears were quiet until about two month ago.

 

Your letter didn't specifically state the third member case as being new. I would put the odds against it for an aftermarket case but factory cases can crack. That might explain things. When the axle is apart on a bench the alignment is fine. Under a load the crack opens a little and your alignment goes away causing a whine. That would also explain why it suddenly appeared. The main spot for cracks is around the 3rd bearing on the pinion allowing deflection. It may be a good idea to wash it all down clean and carefully inspect for cracks. It would be better to tear it apart and magnaflux but then you are talking about spending a little money. You will be happy if that finds the problem but PO if it doesn't.

 

Sent it to Ford specialist & he found the problem, ring gear bolts were hitting the case during torque load. Solution: grind out case. Thanks for your replies.