Normal Whine?

[bigfj62]

I recently picked up a 97 FJ80 with 170,000 miles on it. I have driven it about 1000 miles. I am noticing a gear whine that starts about 45 mph and runs through about 55 mph. It is only when the accelerator is depressed not coasting. It does not seem overly loud but not sure if it is normal or not. Does anybody else hear this. Thanks

 

[superstan26]

I have a high pitched gear whine that sounds like it emanates from the transfer case. Mine is likely more pronounced than yours from your description as it has a broader range of speed and it's moderately loud however it does go away when coasting. I think it is normal with wearing of the gears, but I noticed a significant reduction of noise with fresh oil in the t case. My cruiser has nearly 300k miles on it.

 

[bigfj62]

It sounds to me like normal Cruiser T-case whine. TC has fresh gear oil.

 

[Kernal]

My 96 FZJ-80 with factory lockers has the same whine, started about 30,000 miles ago, removed front driveshaft, noise stayed the same, put in a heavier weight gear oil in the rear diff, noise became quieter. After ~30K miles the noise is still there, worse under load, goes away when coasting, comes back as I start up a rise in the highway. After talking to the Mud experts and a couple of diff rebuilders the consensus seems to be worn carrier bearings and/or pinion bearings in the rear diff. As it was explained to me the noise is caused not by the bearings themselves but by the mismatch in the pinion gear teeth and the ring gear teeth caused when the bearings lose their preload allowing the ring and pinion to move outside of their original (correct) positions when under load.

 

[CJF]

Definitely worth pulling the driveshafts (one at a time ) to check for changes in the noise.

 

[superstan26]

Definitely worth pulling the driveshafts (one at a time ) to check for changes in the noise.

Not a bad idea. If you decide to go this route you'll need to engage your center diff. lock in order to drive so you can perform the test.

 

[bigfj62]

Good points guys. I guess a re-gear may be in order for the lift and tires I want. LOL.