Rspct2All

I'm getting a humming noise when I'm driving at high speeds.
Anything above 50mph is when it gets noticeable.

Does not sound like the tires, since they have good tread and good inflation.
While driving you can only produce the noise when accelerating.

Is it the transmission, rear diff, gears, bearings, ujoint, ...?
I'm just listing those that I've seen on the web searches...

Thanks in advance for the help everyone!

algranger

Could possibly be your ujoints.. check them for obvious slack

algranger

whens the last time you greased them?

Rspct2All

I bought the 4Runner in May 2007 and didn't have any records of previous maintenance done. From a Nissan Dealer
UJints... What is it's purpose?
I will do my homework, but thought I'd get someone's own definition before I read a bunch of what,where,how stuff
THANKS algranger, this feels like it'll point me in the right direction...
Anything that requires greasing sounds right for the issue to me at the moment...

algranger

Are you asking waht/where the ujoins are?
the problem could also be in your rear end but i dont know much about that haha.

Rspct2All

lol, no worries, i know where that is, haha
U Joint, aka universal joint.
The part that's connected to the driveshaft on the rear diff end and the transmission end... I'll see if that applies, this is only at some other SUV set ups...
Thanks again!

Mic09dcsm

Sorry for the thread jack, but if your driveshaft has slack your u joints are on the outs??

904_runner

Grease them and see if it helps.

algranger

Sort of.. if there is slack in the ujoints, allowing the driveshaft to wobble, then yes. The needles are worn out and the ujoints should be replaced

JCBM123

I am having the same issue with my 2001 4runner. Many folks suspected the wheel bearings, but my mechanic said there is no play in the wheels to point to a wheel bearing problem. But I am not sure he did a thorough check. I have fairly new Goodyear tires on it, the Goodyear tech recommended rotating the tires first, then checking again.

Rspct2All.. has the problem been resolved on your vehicle?, and I hope you don't mind giving us an insight.

Thanks
OO

YotaNewbie

I picked my '99 SR5 Sport up on Friday after having the inner rear axle seals and subsequent rear brake damage replaced, as well as the two rear driveshaft u-joints.

When I first picked it up and drove it around town a low speeds, it seemed fine: smooth, quiet, no shimmy or vibration. When I got it on the highway on Saturday morning, however, it was a whole different story.

At about 45 mph it starts making loud humming noise with a slight vibrating sensation, and that sound continues up to 70 mph, which is as fast as I got it. The noise almost intensifies when I let off the gas at that speed and I can hear what sounds like a heat shield under the car start rattling.

I was supposed to make an almost two hour (each way) trip for this weekend but I turned around as soon as I realized something was not right with my car. After reading a bunch of threads here I think they probably put the driveshaft back in out of phase or something. Unfortunately, the garage is closed until Tuesday so I'm stuck for the weekend.

JCBM123

Hmm.. Sounds really interesting YotaNewbie. Seems to be the same thing mine is experiencing. I just got mine, and the maintenance record on it shows some work around the U-joints within the past year. I wonder if it is related.

brian2sun

Rspct2all, YotaNewbie, and JCBM123,
When you check your driveline, it is normal to have a small bit of play clockwise/c.c. wise. That is just your gears' teeth rocking between eachother. If the driveline shifts up and down or side to side, your u-joints are bad.

YotaNewbie

Well, I originally brought mine in because I thought the rear u-joints were squeaking, but the mechanic said it was my rear brakes due to inner axle seals which had failed, thereby allowing the gear oil to leak out and contaminate my brakes. It's a bummer, too, because I just had the rear brakes rebuilt last December when I had my rear wheel bearings replaced.

Anyway, the mechanic initially told me my u-joints were fine, but then when I stopped in on Friday at noon to pick it up, lo and behold my driveshaft was sitting on a table having new u-joints put in. I guess after he'd done the seals and brakes, the squeaking noise persisted.

I have no problem replacing the u-joints, but the resulting humming and vibration is definitely a problem. I've been on lockdown all weekend, unable to travel, because these guys didn't put my car back together correctly and clearly the shop is closed for labor day weekend.

I'm hoping that it's a pretty quick and straightforward fix to make this right again.

moaky

It seems like everyone else knows what they are saying with the u joints. but we just did the cash for clunkers and our 95 runner was making the same noise and they said it was the tranny. it was a high pitch hum. hope its nothing big.

JCBM123

It looks like really bad news for me, as the Mechanics have narrowed it down to a bad pinion bearing. And it happens to be the other one.Yeah, that pinion bearing one that you pretty much have to pull the differential and axles apart to reach because, not the one you can access from the driveshaft side. I wonder why Toyota would build the system that way; the mechanic said you could access the pinion bearings on Chevy via both sides, without having to tear down the differential and axles. I'll keep folks updated.

YotaNewbie, it this happens to be the case on your vehicle, then it looks like the Techs messed up when they re-assembled your axle. Goodluck.

stevomcgee

I had this same problem for a while. The faster I drove the louder and higher pitched the noise became. Like a jet engine but not as loud obviously. Even when I was sitting at a stop light something would stick to where I couldn't move forward unless I gave it a lot of gas. Almost like something had break apart to start moving again.

I had a trusted mechanic (and good friend) look at it and he said the entire rear section needed to be replaced. He opened up the back axle housing and found metal shavings everywhere. I also had the pinion replaced but that didn't really solve the problem.

My suggestion is to have an honest mechanic look at it. Don't go to a Jiffy Srewb or anywhere like that. It cost me about $1200 for a used rear axle and labor when others were quoting $2500+.

Ironmike4x4

They don't always have to have play in the wheels to make noises. Cadillac Devilles are notorious for this until it does get bad enough to cause free play. The shake the wheels trick doesn't always do a good diagnosis. I've been fooled by this once. The best way is to get the wheels moving and use a mechanic's ear to be 100% sure.

akaphilly

i had the noise between 50-60. after i put larger tires on. first thought it was cv's so i replaced both..and it still was hummin.. then got poly steering rack bushings and the hummin was gone!

YotaNewbie

I brought my truck back to the shop this week and they ended up having to replace the new u-joints they'd just put in because they were clearly not compatible. The shop I went to doesn't specialize in Toyota's, they work on Range Rovers primarily, but I like the guy and I think they typically do good work. They got the new u-joints from Toyota and it's smooth as silk now and quiet. Obviously there was no additional charge, either.