driveline thumb, maybe help!

[gbc]

Hey everybody,

I noticed this thump/clunk/bump metal sound coming from mid/rear of my 4th generation sport 2006 4runner. I tried to isolate the problem but failed... I am by no means a mechanic or have any knowledge in this field to make a proper assessment.

Basically, when the vehicle shifts front to back or side to side by a combination of brakes/bumps/physics/whatever I notice this annoying thump metal sound....sounds almost like a spring or like as if something was out of place and hitting something else. I wont hear this thump when I drive in a straight line and the terrain is perfectly straight, at least thats my perception but I could be wrong.

I am almost certain that when the vehicle loses center of gravity somehow the noise manifests itself

The only way I could reproduce this thump consistently is when I go over those speed bumps. So I researched the forum and the closest thing I found with matching symptoms would be driveline thump issue?!

What could it be?? Take these factors in consideration even if they don't really seem to fit in. I changed my tires(to winter ones), and seem to recall the noise shortly after....also the temperature has dropped a few degrees....

thx :S

 

[scottm]

Sounds like someone needs to get underneath and see what is hanging loose. Not likely a major driveline or structural part, or you'd have worse symptoms. Did the spare tire get dropped or even lowered by whoever changed your tires? Could be they didn't get it back in place.

Where are you? Maybe someone here is close by.

 

[eskimochaos]

Lube your shaft.

 

[scottm]

Lube your shaft.

I'm thinking no on this one, sounds like side-to-side motions, and speedbumps are normally with little torque on the driveshaft. The tire guys left something loose, and I'd start with the spare tire.

 

[eskimochaos]

I'm thinking no on this one, sounds like side-to-side motions, and speedbumps are normally with little torque on the driveshaft. The tire guys left something loose, and I'd start with the spare tire.

Yea but speed bumps cause the rear end to compress, causing the drive shaft to "compress".

When I get the thunk, speed bumps cause it to happen as well as aggressive braking.

Check spare tire and tool set in trunk.

 

[gbc]

yup I checked the jack this morning and everything seems to be tight. I also checked all the other compartments and everything is good.

I am the one who changed my tires and I didn't touch the spare tire. So I guess drive shaft is the culprit?? what are we talking about in terms of repair/patching/greasing ??

Any other observations or tests I could do to isolate this problem?

thx again

 

[James_T]

yup I checked the jack this morning and everything seems to be tight. I also checked all the other compartments and everything is good.

I am the one who changed my tires and I didn't touch the spare tire. So I guess drive shaft is the culprit?? what are we talking about in terms of repair/patching/greasing ??

Any other observations or tests I could do to isolate this problem?

thx again

Hm, this is a long shot, but check your rear brake calipers. I reinstalled my calipers a while back, and didn't tighten one of the mounting bolts enough, and sure enough, it fell off while driving, allowing the caliper to swing and "clank" against the side of the hub while stopping and accelerating. You don't even need to take off the wheels to check, try moving the caliper by hand, or observing if the bolts fell off by crawling under the car.

 

[Doozi]

Double-check your spare to be sure... it may have lost some pressure and is able to move around a bit, but I agree with lubing the driveline. 3 zerks on each driveshaft... 2 u-joints and 1 slip joint. It's an easy job with a grease gun that has a flexible hose... just don't go overboard. The u-joints will "crackle and pop" as you fill them with new grease and displace the old so stop and wipe off the excess when you hear it. Adding grease to the slip joints is a little more vague... I didn't hear any noises or witness any seal expansion, but you definitely don't want to over do it. Maybe 10-15 pumps of the grease gun and I've heard that it's best to do the rear shaft with the rear axle at full droop so the slip joint is fully extented.

If that doesn't reduce your noise, crawl around under the 4Runner and check everything... gas tank skid, exhaust system, etc. and check back with us.

Good luck,
~Doozi