i have a problem, and it kinds sounds like the problem that clint(swampthing) has... when i take off from a standstill i get a whirring/grinding noise coming from under my cab somewhere... i first thought it could be the transmission fluids being low, but i changed that, and other than it looking like gooey tar, no change in noise... next, thought it could be due to tires being out of balance and howling, but after getting them rotated and balanced, noise is still present, but now its getting louder...

now im stuck either thinking that its the front passenger CV axle because it recently let loose, or something much worse in the tranny/transfercase/rear dif.

any ideas??

oh, and the whiring gets louder as i accelerate, but goes away as i press the clutch in, and returns after a gear shift...

 

is the noise consistent with vehicle speed or engine rpm?

 

yup... faster i go, the louder the whirring gets... im to the point where i just turn the radio up so i dont have to hear it anymore... i know thats one of the worst things that i can do, but im at a loss to what is making the noise...

 

So to confirm, its proportional to vehicle speed and stops when you press the clutch? Have you tried putting the t-case in the different gears and testing that? Maybe try putting the tcase in neutral and running the tranny through the gears, if it's coming from the tranny then "theoretically" that should isolate it.

By the way, I'm in NO WAY WHATSOEVER an expert on the matter. I have however spent the last 2 or 3 days trying to figure out a strange wirring from my truck which I think I've narrowed down to shotty wheel bearings. So just trying to help you with things that I tried that might relate to your situation.

 

It could also be caused by a bad throw-out bearing.
But take country wheeler's advice 1st and run it through the gears with the T-case in neutral. Does the noise get better for a moment after you shift?

Any improvment?

 

Do the 4runners have a hanger bearing?

 

4Runners use a one piece driveshaft, no carrier bearing.

If the noise goes away when you press in the clutch, your throwout bearing is toast.

 

I think that's backwards - if the throwout bearing is going you'll hear the noise when the clutch is pressed in, not the other way around. That bearing ain't doing anything when the clutch is engaged. A noise that happens constantly but disappears when you disengage the clutch sounds more like a transmission input bearing, or a needle bearing under a gear, or something else internal to the transmission.

 

When I fired up my 3vz after the conversion , I had forgotten to put ATF in the P/S reservoir, and had a loud whirring noise, consistent with engine speed, filled the reservoir and away it went.

 

Yup, you are correct. Doh.

The input shaft stops spinning when you press the clutch in, so you are right, i would look at the input shaft bearings.

 

okay, so i spent 5 minutes trying to figure out how to put the transfercase in neutral, but i finally did it... i put it thru the gears, and no, it doesnt make the "whirring" noise, so i guess i can rule out the transmission...
maybe the transfer case or rear dif??? any ideas? i know that this is the same problem that swampthing is having...

 

thanks for the advice about the P/S res. but i know for sure that isnt the case since i put P/S fluid in it about every other week...

 

I hope you put ATF in your reservoir and not power steering fluid.. the PS systems on these trucks don't take power steering fluid.

 

yea... i found that out through another thread and i need to drain the P/S fluid and refill with ATF... thanks tho!

 

Update... still havent found out what the noise is, but it got worse today... Ive been driving all morning, and when i stopped today to get a Full Throttle vanilla coffee(the best ever) and started my truck back up, i would get up to about 30 MPH and the whirring turned into a horrible grinding noise... it only grinds 3rd thru 5th... but the worst is 5th now... i can actually feel the vibrations coming through the shifter that correspond to the noises that im hearing...

here are some pics, and a really crappy video...

 

Was the truck in gear when you took the video??? If it was, then your rear Diff needs to be rebuilt. Have you checked the fluid level in rear axle? Does your axle leak??
The reason you don't hear the noise at lower speeds is because the gears aren't turning fast enough to make much noise. I had a similar problem with mine, but I knew what it was. So I was able to get it fixed pretty easily. The diffs in Toyotas are easy to change. You can get a rebuilt one, a used one or have yours rebuilt. I bought a rebuilt from Jaws Gear and Axle, because I didn't have the time to get mine rebuilt.

PM me if you'd like,
Grant

 

U-joints or rear diff. I gernaded my rear a few years ago. Just drain the fluid you will see nice chunks of gear splines. If the noise goes on under accel and goes away after decel sounds like R&P.

 

crap!!! i took off the fill plug and it was one of the most horrible smells ive ever been in contact with in my life... the oil looks like tar, and i dont have a socket big enough to unscrew the drain plug!!!! anyone know the socket size for the rear dif drain plug???

 

24MM socket

 

Thanks DC!