If you've got gear whine, the issue is probably in the pattern of the gear mesh. That's a shimming/setup issue, no amount of fluid change will fix it. However, if caught early, a competent mechanic can reshim the gearing and fix it.
Got car back from dealer they reinstalled Gears in the rear end . Quiet like it should of been!! Now putting stock resonator back on with roush axle back to have a civilized sports car!
Took mine in for the same thing on the same day, just got a call that they got it back together and now a new noise has come up. They have to replace the Ring and Pinion and takes 3-5 days to get. Starting to get a bit worried that maybe this rear end specialist doesnt know what he is doing.:frusty:
Yup that's what it is. Are u at a big dealer? Find out who has been there the longest. I'm getting no noise now and especially since I put back my stock resonator and kept just roush mufflers sound awesome. Only noise I get is from the tires a little might need to get fronts balanced