Hello Everyone,
I have a 1997 4Runner, 272,000 miles, 4WD, AT, 3.4L I purchased about a year ago.
I have an audible humming/whirring/roaring sound at 40-50mph I am trying to diagnose. Becomes more audible when you let off the gas and coast at these speeds, you can even feel a light vibration in the floor and steering wheel. somewhat noticeable at lower speeds, goes away above 60mph.
Ive been chasing this for about 3 months now while performing the below maintenance and hoping that solves the issue:
Is this a problem? -
1997 4RUNNER transfer case output front driveshaft. - YouTube
-Is the transfer case output to the front driveshaft supposed to have some gear/chain noise? Or is this a bad bearing? I thought this didn't rotate in 2 wheel drive? would it still make noise?
I also replaced the engine when I first got it due to failed cylinder #2. So I'm now getting the rest of it in order.
-Replaced the rear differential with known good used one.
-Replaced the rear wheel bearings and seals.
-Replaced the front wheel bearings, seals, and hubs.
-Replaced the front differential driver needle bearing with ECGS bushing.
-Separately replaced the front lower and upper control arm bushings.
-Changed rear/front differential fluid & transfer case fluids.
I considered road noise from newer cooper AT3's. But I'm still getting this coasting noise when the car is in the air, see videos.
3rd gen 4Runner rear noise2 - YouTube - Noise at rear differential.
3rd gen 4Runner rear noise3 - YouTube - Noise at rear drive shaft.
I'm hoping someone can help pinpoint the problem from the description and video. I don't think this noise is normal and I assume it will only get worse if I leave it.
Thanks.