So while cruising around I hear this loud howling coming from the rearend. At first I thought wheel bearings? But then I realized it only happens in 4th gear around 2400-2600 rpms and in 5th gear from 1800-2000 rpms. When I had it in the air a couple of weeks ago the housing looked in good shape with no leaks or cracks. Anybody have any advice as to what it may be?
You are positive you don't have the same sound in that rpm range using other gears? My first thought would have been like you - wheel bearings. Then I would check rear differential fluid levels. You might be low, or it might need changing. If you plan to replace fluid, make sure to remove the fill plug before you drain the differential.
Absolutely positive, I havent really hit higher rpms (nothing more than 4k) in 1st-3rd but no howling in those gears under that rpm. Another reason I suspect the rearend is because it only does it when theres a load on it. If im in the range of when it normally howls, and i let off. It goes away considerably. I think maybe this weekend I should replace the fluid just to see if theres any change.
I suspect wheel bearings or tires. Here's why...when you say is is only between this RPM and that RPM in X or Y gear, you are actually saying it is speed dependent. You might not hear it in 3rd because the engine or exhaust/intake is drowning it out. IF it was the diff, you would hear it in all the gears.
My colleagues NA had a mud wasp clog the vent hole which pressurized the case when it warmed up, blowing the oil out the seals. He replaced the fluid, it still hows but hes been running his this way for a year and a half.
I've got a slight whine from my rear end as well, sometimes I think it might be tires.
If it's definitely coming from the differential, and not your wheel bearings (it will sound like you're sitting nearly right on top of the source of the sound) it's your pinion bearings.
Im really hoping its wheel bearings! But I never been one to just throw parts at a car hoping it fixes it. So when I throw it in the air again ill see if I can recreate the situation
If it is your diff, it will break the R&P soon. They really don't like to be misaligned. If you are at the diff howl stage, it will go shortly.
I get a howl from my rear end now with poly differential bushings, it sounds like all the diff whine gets directed into the body. At first it scared be but I have grown to like it.
I don't mean a loud howl, just a distant whine.
I would listen to kung fu tho:
If it is your diff, it will break the R&P soon. They really don't like to be misaligned. If you are at the diff howl stage, it will go shortly.
Could you expand on that a bit more? For science...
Wolfgang Pauli summed it up nicely.
That should keep you busy for a while.
Put it up on jack stands and use one of these to find out which bearing is singing.
In my case it sounds like it's coming from behind my left ear when driving.
Thats exactly how mine is, i can hear it really pronounced in my left ear.
Wheel bearing, assuming you're in a left-hand drive vehicle.
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