'Humming' noise from rear end

[Kung]

I've been so involved with tracking down a vibration issue with my 4Runner (which has FINALLY been solved - 2 out-of-round rims) that I completely missed this one until recently.

Long story short, it starts to 'hum' above about 55 or 60 mph, and ONLY above those speeds. Below that it's quiet as usual. It doesn't appear to abate when the gas is let off; it seems to be directly linked to the speed.

I'm guessing either rear wheel bearing(s) or possibly torque converter, etc. Any suggestions on how to narrow it down? I've got an appointment with the hobby shop on Fort Leonard Wood on Monday (yes, they're actually open Monday) but I'm curious if there's anything I can do myself to assist.

 

[jmildoc]

I had that same problem not too long ago and ended up being a rear u-joint. super easy fix if you have a vice, hammer and some sockets. also i think it was about a $12 part so not too bad.

 

[Kung]

I have all of the above, but what I don't have is a ton of time. LOL

That being said, I usually pay like $40/hour for labor, and almost NEVER get charged the full rate, so we'll see what they say. I'll keep that in mind - thanks for the info.

 

[Bama_Runner]

I have this hum as well but mine shows up at 25-30 and then again at 75. I have replaced U-joints and it didn't help. Next I am going to have the balance checked on the drive shaft. Then, if I still have it, I'm going to check out the axle bearings and then the pinion. I have had this issue with 2 sets of wheels and 2 sets of tires, so I'm positive it's something in the driveline now.

 

[Kung]

Well, I'm pretty positive that the driveline was checked (when trying to find out what was causing the vibrations between 55 and 75 or so), and the vibration is NOT there now, so while it MIGHT be U-joints, I am leaning away from that.

I'm guessing it might be bearings. (Whee!)

 

[KidVermicious]

Well, I'm pretty positive that the driveline was checked (when trying to find out what was causing the vibrations between 55 and 75 or so), and the vibration is NOT there now, so while it MIGHT be U-joints, I am leaning away from that.

I'm guessing it might be bearings. (Whee!)

Find a highway with some corners, and see if it gets better or worse as the truck leans back forth. If it doesn't, that kinda shifts it away from it being a wheel bearing, tho it doesn't rule it out.

 

[Kung]

That's easy - I can do that on the way home. 28 North (the road I take) is curvy as hell. LOL

 

[PitbullRescuer]

U joints don't hum, they vibrate. Anytime I've ever had an issue like this, it's always been a pinion bearing. Debatable if it's worth fixing or not.

 

[bergeron37]

I'm in the process of buying a new 3rd member because of a similar problem, see my thread a few pages back.

I ran my 3rd out of gear fluid and that was pretty much it, its ****ing annoying as hell.

 

[Kung]

U joints don't hum, they vibrate. Anytime I've ever had an issue like this, it's always been a pinion bearing. Debatable if it's worth fixing or not.

Y'know, I thought that might be the case as well - I thought "If it was wearing out, it'd probably seize up a bit, in which case it'd vibrate." Thanks for that.

 

[Kung]

U joints don't hum, they vibrate. Anytime I've ever had an issue like this, it's always been a pinion bearing. Debatable if it's worth fixing or not.

Forgot to ask - why debatable? On the one hand, I don't mind buying a new vehicle if I have to; this is our dependable 4WD vehicle.

On the OTHER hand, we have no car loan, so I'd rather not get into one if I don't HAVE to.

 

[PitbullRescuer]

Still drivable with it humming. I had a Grand Cherokee that was humming for years. I had a Yukon Denali that started humming right out of warranty. I finally fixed it 100,000 miles later. Debatable because its not really necessary to fix it. Try changing the diff fluid & adding some Lucas to it.

 

[Kung]

Still drivable with it humming. I had a Grand Cherokee that was humming for years. I had a Yukon Denali that started humming right out of warranty. I finally fixed it 100,000 miles later. Debatable because its not really necessary to fix it. Try changing the diff fluid & adding some Lucas to it.

Oh, those are a given, for sure.

 

[Kung]

Good news - we were at our friends' house last night, and they were in the middle of installing a new stove. (On a side note - they're giving us their 'old' stove - which isn't old at all. LOL)

ANYWAYS, their uncle used to work for a dealership, and he said "Oh, if you need someone to work on it, I'll do it for you." Evidently he's one of the best around, and he is with mechanics like I am with computers - he does phenomenal work and for dirt cheap.

They'd had to replace an engine and a rear end in a vehicle and the dealership charged them (or wanted to) like $2500. He charged them $600. LOL

SO he told me if it came down to it he'd charge me $200 or $300 plus parts. Now THAT I can handle.