Another vibration question

[DEF4Runner]

This site has been amazing! I've learned quite a bit about my rig since I joined and thank everyone who has contributed. I've searched for a while and collected a ton of possibilities regarding a vibration I'm having on my 08 V6 4X4 at 147K. Trouble is, and maybe it's the way I'm searching, this one seems unique.

I have a high frequency vibration in the front end most prominent during decelerating from 30mph to about 15 or so (it might be occurring during acceleration, but the engine vibration would drown it out). While decelerating, I'll get a rhythmic rumble strip-like vibration...or like ripping the perforated zip top off of a small cardboard box...seemingly coming from the FR side, giving me a cell phone-like buzz in the steering wheel, gas pedal and floor board. When I say rhythmic, it sounds like: vrrrr, vrrrr, vrrr,...2-3 seconds...vrrr, vrrr, vrrr. At this point, you might be saying wheel bearing, BUT...it only happens in 2WD. Put her in 4WD and it stops.

I serviced the front diff about a month and a half ago, the second time it's been serviced. Instead of OEM fluid, I used M1 75-90 LS and filled to the owner's manual spec. I've noticed it's taking longer to engage 4WD since the service and can't help but wonder if that's my problem.

Going through my searches, M1 'seems' like a perfectly good product...running in plenty of 4Rs out here, but what's the likelihood my rig is just having a tantrum over it versus actually having damaged something else, like a carrier/pinion bearing?

For those that might ask, I've done the figure 8/turning left and right to isolate a wheel bearing, but no dice. Didn't help. I was kinda hoping that's what it was. Replacing those is kinda easy. They aren't completely ruled out though.

I'm planning to replace both axles when it warms up as the inner boots are leaking so I'm gonna swap the fluid again anyway. Has anyone else experienced this same vibration who can recommend what I can look at while I've got the wheels off again?

Thanks!

 

[fdbyrne]

If it stops when you put it in 4x4 it's very likely the driver side differential output shaft bearing. You won't find much about it on this forum, but if you go to a Tacoma forum and do a search for 'ECGS bushing' you'll find a lot of people that have that same vibration.

 

[DEF4Runner]

Could it be the inner CV joint itself? If it could, that would be a relief since I have new axles in the bull pen, but I always thought CV just clicked when heading south.

 

[fdbyrne]

I guess it's possible. Swapping out the bearing for the bushing isn't much more work that just swapping out a CV shaft.

Grab the inboard side of the CV shaft and try to move it up and down, left and right. How much play is there?

 

[DEF4Runner]

Just went outside to check. Absolutely no movement in the passenger inner axle. It's tight. Went to the driver's side...considerable wobble. Probably has ~ .25 inch or more of play.

 

[DEF4Runner]

This is exactly what it looks like:

https://www.youtube.com/watch?v=PEjqtDg9gUs

 

[fdbyrne]

Don't take my word for it. I'm not a mechanic. More of a tinkerer than anything. It sounds like the same problem to me though.

Do some research in the Tacoma forums and see if you think it's the same issue. Search for 'ECGS bushing'.

If you want to swap yours out you can borrow my bearing puller. It'll save you $60 or so.

 

[DEF4Runner]

Thanks!

I checked out the ECGS site, watched the videos and I believe I have a winner! Looks like I can add this to my list of springtime repairs. Any idea how long that bearing has before it gives out? Wondering if I can even make it to spring before I dig in and have to replace it. I sure don't need the damn thing to FOD out (Foreign Object Debris) in the diff.

 

[fdbyrne]

I've read a lot of stuff online about the front end vibration and I've read a lot of accounts of people going years before figuring out what the problem was and fixing it. I don't recall hearing any reports of the vibration starting one day and the differential failing violently in only a few weeks or months but you never know.

I've installed the bushing into two vehicles, a 1st gen Tacoma and a 4th gen 4Runner. It's the same process and it isn't that hard if you have ever done a CV shaft before. My advice is to just plan on doing it as part of the CV shaft job that you already have planned.

Let me know when you want the bearing puller. Send me a PM or something. They have to be modified a little to fit right and I already modified mine so that'll save you some time too. It's really not a hard job, assuming that you've done a CV shaft or two of course.

Might as well get a differential seal too since everything else will be new. Get an OEM one. They're cheap and have a better fit than any of the OEM ones that I've used.