high pitched whine from rear?

[cantspell]

hey there, i have a high pitched whine comming from what i think is the rear diff when i'm at higher speeds and OFF the gas, it only occures when the RMP's drop below 1K or so...is there a bearing back there in the diff that would make that sort of sound?

 

[BrooklynBay]

I had that same problem, and I couldn't find it at first. I asumed that it was a bearing, but it turned out to be the U joint. I figured it out once the U joint got worse. It stopped whining, and started to click every time I tapped on the gas pedal, then clicked again when I let go.

 

[rmcknight]

with the car on the ground, try and turn the rear axle back and fourth with your hands, if there is any play at all in the U joint area it may show up. My money is that its not bearings either, its probably the pinion i.e. the gears are a bit worn. If so its no problem at all. how many miles has it done?

 

[cantspell]

i have 240K kilometers...actually, the U joint was mentioned as well...but i've had ujoints go and it's usually more of a click sound...i'm going to bring it in to the tranny shop i go to today...

 

[rmcknight]

can you hear the noise more or less on 1) light acceleration 2) accelerate to say 80 and coast 3) when traveling 80 the point where you hold the foot down to just keep it at 80.

 

[cantspell]

it turns out it seems to be the transfere case shift motor, it's not disengaging fully....? i'll find out for sure tomorrow/

 

[rmcknight]

I dont see how that would not cause a wine! It may cause more power to go the the front or back wheels than it should but no noises. My money especially with 240K is gear noise in the diff! The transfer case has clutches and plates with oil creating friction, no parts come in contact to create noise!!!!!

 

[cantspell]

ok, well here's the thing, the whine correlates with the engine rpm's... so we think it's SOMETHING in the transfere case...as the diff is spinning at a constant speed relative to the wheel speed...does this make sense?

 

[rmcknight]

does it do it in neutral and or in overdrive (5th)? ie i am trying to eliminate the transmission.

 

[cantspell]

it does it in both - BUT, it spikes when i manually down shift...and it certainly seems to come from the rear of the veh...??? so the transfere case or the rear diff? and only when the rev's drop below 1K.

 

[rmcknight]

the transfer case is in the front of the vehicle, well front middle?
the noise would come from under your feet if it were the TOD system. So we are back to rear diff? By the way - thats the best thing to go wrong, if its a wine noise and even a clunk when you hit the gas hard for a second its going to be the diff.

 

[rthall003]

So we are back to rear diff? By the way - thats the best thing to go wrong, if its a wine noise and even a clunk when you hit the gas hard for a second its going to be the diff.

I have the same thing. Whining on acceleration and just recently it basically started doing the same noise - going down in pitch though - on decceleration. When the decceleration noise started, the clunking started, too. It clunks consistently after slowing down to a complete stop sometime between moving my foot from the brake pedal to the gas pedal. This is on my '98 5.0 2wd.

Is rebuilding the diff the only solution here? Thanks in advance!

 

[rmcknight]

diff and bearings i think. if its a LSD it could be a bit more $, if its not a LSD you should consider putting one in! my guess is new pinions 2 or 4 + bearings will be less then $500 U.S.D

 

[rthall003]

Whoops i forgot to mention, I do have the LSD

 

[rmcknight]

Its a job not easily done at home! Let me know how mutch it costs once you get a price, or just drive it until the noise gets worse and constant.

 

[rthall003]

I got quoted $550 from a gear shop in Tulsa, OK... seems fair to me I guess.

 

[rmcknight]

Do you know what they think it is and what they will replace for that?