Vibration from rear end.... happens like this

[CanuckQx4]

Im curious where to start looking for a vibration that Im now getting on my truck.

I get a good vibration, almost like the rear end is bouncing under light braking and low speeds. I get the same sort of feeling when I take off for the first part of the rpms.

The car rides completely smooth while cruising though.

What would cause such vibration or be a good place to start. I verified tire pressure, and checked my trailling arm mounts and all was fine

[Towncivilian]

Perhaps check for play in the rear driveshaft?

[CanuckQx4]

Just grab it and wiggle?? I can do that.

I did have an incident where the car rolled on me with the trailing arms disconnected and the rear tires went forward into the fender and the rear end kind of tilted up......

Never thought about the driveshaft for this kind of vibration but I guess it could be!!

[CanuckQx4]

I noticed on the drive home tonight that if you give it alot of gas it will make the vibration feel, but it will be a little less violent but alot more rapid

I'll climb under it when I wake up if it doesnt snow

[Chuck Tribolet]

Does the vibration frequency vary with speed? If it vibrates faster as the car goes faster, it's something that's rotating.

Chuck

[CanuckQx4]

Well I notice it does it almost EVERYTIME I brake at low speed, sometimes when I accelerate fairly slow from a stop

Im going to inspect my driveshaft very well today since mine is a 2wd and not to many parts are rotating

[CanuckQx4]

So I climbed under the car to check out the driveshaft.

I think I may have found the problem, in the middle of the driveshaft there is a U shaped cradle that bolts to the chassis on both sides and looks to support the driveshaft, there is a good 3/8" - 1/2" of play in the driveshaft at this point. I can move it around fairly freely

Should the driveshaft be solid in this cradle??

Heres a few crappy pics

Front


Back

[Chuck Tribolet]

I went under my '01 PF 4X4 and I don't have that. I suspect it replaces the 4x4 take off for the front wheels.

However, I don't think there should ever anywhere near that much play in a drive shaft. I've seen some bad U-joints and they
didn't have anywhere near that much play. Wait for a second opinion, but I wouldn't drive it with that much play.

Chuck

[Towncivilian]

If nobody else replies with an answer by tomorrow afternoon I'll crawl under my PF and see if my 2WD has that, and if so, check for movement.

[Buzzman]

Even after all these years, I'm still amazed to see that Pathfinders were produced in a 2WD configuration.

[Towncivilian]

Even after all these years, I'm still amazed to see that Pathfinders were produced in a 2WD configuration.

Believe me, I don't prefer it, but I got my PF as a hand-me-down from my mother, so I can't complain.

[Pathfound49]

Thats the carrier bearing. About the position that the back end of our 4wd transfer case is.

[Chuck Tribolet]

Actually, I would have preferred that my '87 PF were 2WD. It was a dog-hauler and I never used the 4WD. The '95 and '01
have made good use of 4WD on slippery launch ramps.

Chuck

[CanuckQx4]

Only thing that has me slightly happy is that the joint looks serviceable

Looks like you can take those 2 bolts out and the cradle would come off and the bushing or part could be replaced

I dont quite get how tight it should be or if this could be the source of the vibration

ps- I love that my qx4 is 2wd, I never would use 4wd and I like its compared simplicity

[CanuckQx4]

bump for good vibrations

[CanuckQx4]

so is that "bushing" serviceable?? And could it cause this problem??

[1wizeguy]

U-Joint.
I had the exact same problem were under heavy acceleration I'd get a bad vibration.. I took the drive shaft out and the rear u-joint was frozen

[CanuckQx4]

guess I better learn what a u-joint is on out driveshaft and check mine out!!

Was it an expensive part?? Any difficulty to the fix?

[fleurys]

about 30$ part (after market at neapco) and about 1 hour of work. If you can use a vise, a ratchet and a hammer, then you can change a u-joint.

[Pathfound49]

And if you can dodge a wrench you can dodge a ball.

[CanuckQx4]

Im not to familiar with anything beyond the engine so Ill have to snap some pics and come back and get some help from you guys on how to go about this. Only one u-joint Im assuming (can you tell Ive had a FWD Honda my whole life lol??)

[fleurys]

no..There is 2 u-joints in the rear and 2 in the front (for a 4wd).. check your fsm.. it's all in there...

here's a not so bad video of one way of doing it. : http://www.youtube.com/watch?v=659gVU4QSEg

[CanuckQx4]

mine is a 2wd, so would it be best to just change both?? or just the affected

thanks for the video

[fleurys]

if I were you, I would change both.... because if one is gone, the other will go soon anyway.... mind as well do it while you have the driveshaft in your hand...

[CanuckQx4]

is it possible that the vibration could be from worn upper control arm bushings?? Mine feel a little loose, can twist them by hand, but they are probably factory

[1wizeguy]

My u-joints were frozen and I had to take a torch to loosen them out.. Sounds to me like you should have a shop swap them out for you.. an hour or two labor is well worth hot u-joint grease popping in your face.

[CanuckQx4]

Its been bad weather here so I havent even had time to crawl under the car and inspect the U-joints

It hasnt vibrated nearyl as bad the last week either

I really dont want to fix something that doesnt need to be