Rear End nose while driving

[99ToyoRunner]

I've noticed when I'm driving on the highway and this only happens between 60-70mph there's a vibration and humming coming from the back of the car...It's not a violent vibration but a rather annoying one and the humming noise can get loud inside the car. This only happens between 60-70mph...driving around town the car is very quiet. Plus it starts to vibrate and hum when I go down a hill too but goes away slightly when I give it gas. I know this isn't a normal sound..I mentioned to this to my dad and he said I was being paranoid. But honestly it doesn't seem right. I just changed my rear diff fluid too and that seemed to quiet it down a bit. I'm not too sure what it could be. My 4Runner is a 99 V6 5speed with 158k thanks!

 

[Riceye]

Grease the bejeezes out of your driveshaft zerks. Purge the old grease, and wipe clean. Give the slip joint zerk about 20 pumps, as well. Might as well grease up the front drive shaft while you are at it. And check the fluid levels in the rear and front diffs, transfer case and transmission. You will need to drop the skid pan to access the front diff plug.

I had the same issue when I got mine, and this made a huge difference. If this doesn't help, suspect a bad u-joint.

 

[99ToyoRunner]

Okay..sounds good...I just changed the rear diff fluid unfortunately my skid plate two of the bolts holding it on are completely stripped. Is draining the trans fluid on a manual transmission any different than an automatic? I feel dumb asking..but this is my first manual car/Toyota I've owned. -Thanks

 

[Sherwood4Runner]

I had a similar sound recently and it was caused by a bad u-joint on the rear end of the rear drive shaft. However, start with fluids and greasing the zerk fittings on the drive shaft. Stop squirting grease when you hear a crackling sound. It is in fact possible to over-grease them (according to my driveline shop).

 

[hurt4x]

Grease and check u-joints as mentioned above first.

Since you mentioned changing the diff fluid. Did you notice and abnormal build-up of metal on the drain plug? Could also be pinion bearings going bad.

 

[99ToyoRunner]

The fluid was a bit dirty but no shavings...I'm going home to my parents house tomorrow so I was going to change the trans fluid and the front diff...and change the oil again too. Thanks for the advice

 

[wc11]

Wheel bearing maybe as well?

 

[99ToyoRunner]

It's possible...Once I grease the zerks and change the diff fluid and trans fluid..then hopefully the car won't make the noise anymore. It's strange how it only makes that humming noise and vibration between 60-70mph below 60mph the car is very quiet

 

[Snowy21]

It's possible...Once I grease the zerks and change the diff fluid and trans fluid..then hopefully the car won't make the noise anymore. It's strange how it only makes that humming noise and vibration between 60-70mph below 60mph the car is very quiet

That's exactly the symptoms of my 4Runner when the rear u joint went out. You can check by chalking the tires, put the trans in neutral and crawl under to see if there is slop at the rear joint (or any joint for that matter). Slop=bad u joint

 

[99ToyoRunner]

I made the trip home to NY from Massachusetts (230miles) and 30 miles from my parents home i started to hear what sounded like the drive shaft rubbing on a heat shield when I let off the gas but went away when I applied gas again..but came back as soon as I let off the throttle. So I pulled over looked under the car and didn't notice anything unusual. I managed to get home on the back roads not going over 50mph and the car was fine. I greased all the zerks...there was no play in the drive shaft going into the diff or anywhere. However I have to go back to work Tuesday afternoon and I don't feel comfortable driving the car back to Massachusetts and don't think I can get this fixed before Tuesday...On another note I drove 91.2 miles from Hyannis to the first rest stop on the mass pike and I topped off my truck with 3.4 gallons of fuel. I checked and I averaged 26mpg...Didn't seem possible

 

[99ToyoRunner]

Well thanks for all the input....my mechanic replaced the U joint on the aft end of my drive shaft. The U joint on the car was just ruined but what a difference...no more chunking noises or humming or vibrating over 60mph. I was going to do the job myself I have plenty of experience working on cars but I always second guess myself when it comes to drive train work. Thanks for the responses! Sorry my picture uploaded sideways...I uploaded it from my phone