nagata

I noticed a mild vibration in my 96 GT on Monday. I first noticed it right after I had 2 new rear tires put on (Falken ZE-512 245/45), so I immediately thought it was misbalanced tires, but after going on the highway I'm not so sure.

When cruising on the highway at ~70 mph, I feel the mild vibration and also hear a noise that's best described as a whirring sound, kind of like a mudding tire on the highway. The vibration seems to vary a bit with speed, and below ~55, the noise seems to disappear. The noise and vibration are most prevalent when cruising at a constant speed, they seem to diminish when decelerating or accelerating, and the sound seems to come more from the passenger rear. Now, I've experienced this sound when I had a bearing going out on a previous car, but had no vibration, and it seems odd that it just appeared after the new rear tires. I know it wasn't present before Monday.

I'm gonna have the tires rebalanced, but if that doesn't fix it, think I've most likely got a bad bearing? Or something worse like in the rear diff or axles? I changed the diff fluid on Sunday, the day before noticing, but I didn't mess with internals and filled it back up properly, so I can't see how that would have caused this. Thanks for any help!

madatmk3

Hi, I have a 96 GT that had the same issue. I took the car in to my suspension shop and it turned out to be a bent rear left axle, The sound in my case was caused by the bend in the axle rubbing the axle tube. The bend was caught early enough it didnt tear up the axle tube.

nagata

Well ****...I certainly hope that's not the case! Thanks for the heads up, I'll have to check into that. I haven't put slicks on it or improved traction in any way, no massive burnouts, no hard launches; so unless it was bent by the PO and for some reason I just now noticed it, I'm at a loss for how a bent axle would have happened.

madatmk3

Im not sure if it works this way but I think that once the axle gets slightly bent it can get worse over time. In my case I went through a dip too fast and the rear of the car kinda hopped up and came down hard, it drove fine for a month or so and then the vibrations started. They were also speed sensitive just like your issue. In any case having the axles checked would be a good idea they can completely wallow out the axle tube if the bend is severe enough.

nagata

Alright, well, if having the tires checked and rebalanced doesn't fix it, I guess it's off to a shop, no sense in playing a guessing game. In the event that it is a bent axle, how much did it run you for a replacement, and did you get a new or used one? Do the swap yourself? Thanks again.

massred98gt

wheel bearing

nagata

Well, I had the tires rebalanced and it helped the vibration some, though there's still a small vibration, but the noise is still there. I took a car savvy friend for a ride yesterday to get his input, and he thinks it sounds like diff clutches chattering. So, I'm just gonna go to a shop I know and have him look at it, too many different possibilities without enough experience/time to determine what the true issue is. Dang car is gonna nickle and dime me to death, lol. Thanks again for the help!