Vibrations...Need some expert thoughts here

[Cow_doc.308]

I mentioned the vibration in my runner in another thread a few days ago.

When I'm at cruising speeds (60-75) and holding steady, there is a pretty significant vibration under the seat that seem to me to be from the tranny rearward. If I accelerate or let it coast it dies down almost completely.

I've climbed under my truck several times and there is some up and down play in my rear drive shaft.

To my inexperienced eyes it seems that the only place that gives is the output from the transfer case. The u-joints don't seem to have any play in them and the rear pinion doesn't seem to wobble.

Am I totally off base here? Is it possible that there's a bad bearing in the t-case on the output shaft that allows this play in the shaft?

If I'm way off here (totally possible) what am I missing?

 

[5vzT4R]

I'm a little confused on what you mean by the rear drive shaft t-case out put.. But another thing to check for drive shaft vibration would be your carrier bearing.

 

[Cow_doc.308]

Sorry for the confusion.

What seems to have slack in it is the shaft coming off the back of the t-case that the rear driveshaft attaches to. I'll try to take a picture tonight

 

[ToyOtis]

Do yourself a favor and drop the driveshaft. The rear u-joint may not be sloppy, but may be seized and very stiff.
Eliminate this variable first. It is one of the usual suspects on our trucks.

I would think if the output shaft was wiggling a lot it would allow the stinky contents of the transfer case to puke, and you didn't mention any leakage.

 

[Cow_doc.308]

Yea u joints were the other thing on my list of possibilities. I'm dropping the drive shaft anyway Saturday so I think I'll just replace them while I'm at it.

Also, the carrier bearings were mentioned. Unless I'm mistaken one what a carrier bearing is I don't have one.

Is a 97 sr5 supposed to have one?

 

[ToyOtis]

You have a double cardan joint and a rear u-joint.

I took mine to a driveline specialist and had him replace the rear u-joint, inspect the double cardan, balance and lube. Doesn't take them long, and it should last for the life of the truck with regular lubrication. Best money I've spent, smooth as glass now.

 

[Cow_doc.308]

And the double cardan is non replaceable correct?

 

[02SE]

Yea u joints were the other thing on my list of possibilities. I'm dropping the drive shaft anyway Saturday so I think I'll just replace them while I'm at it.

Also, the carrier bearings were mentioned. Unless I'm mistaken one what a carrier bearing is I don't have one.

Is a 97 sr5 supposed to have one?

You're correct. There is no carrier bearing in the drive shaft of a 4wd 3rd gen 4Runner.

Make sure your 4Runner is secured from rolling, before dropping the drive shaft. I saw the aftermath of a guy that didn't set the parking brake, or block the tires, and the truck rolled over him when he removed the drive shaft. He didn't make the Darwin awards, but he was seriously injured.

 

[snivilous]

Maybe your tuned mass damper fell off.

I don't know how much extra vibration that causes though :noidea:

 

[blonde1boarder]

I had the same issue literally two days ago. The flange output from the transfer case had a quarter inch wobble to it. I dropped the driveshaft and used a 30 mm socket to tighten the staked nut out which got rid of the vibration.

 

[5vzT4R]

You're correct. There is no carrier bearing in the drive shaft of a 4wd 3rd gen 4Runner.

Make sure your 4Runner is secured from rolling, before dropping the drive shaft. I saw the aftermath of a guy that didn't set the parking brake, or block the tires, and the truck rolled over him when he removed the drive shaft. He didn't make the Darwin awards, but he was seriously injured.

Learn something every day.. I did not know they didn't have carrier bearings. I guess since every vehicle that I have owned has had one, I figured why would the 4Runner be different? Lol.....

:doh:

 

[Cow_doc.308]

So I took it to a shop this morning and the mechanic says there is a lot of slack at the rear differential and the tcase. He says he's pretty sure the pinion bearing is bad and probably bad bearings in the tcase. He hasn't pulled it apart to see exactly what all the problem is.

Should I repair what I have, buy a salvage rear end and tcase, or sell the runner and buy another?

 

[02SE]

So I took it to a shop this morning and the mechanic says there is a lot of slack at the rear differential and the tcase. He says he's pretty sure the pinion bearing is bad and probably bad bearings in the tcase. He hasn't pulled it apart to see exactly what all the problem is.

Should I repair what I have, buy a salvage rear end and tcase, or sell the runner and buy another?

What kind of slack? Some rotational play (slack) is perfectly normal.
Now if the output flange at the T-case can be moved up and down and side-to-side enough by hand to see and feel it, then you have bearing problems in the T-case.

Likewise if the input flange on the rear diff moves up and down and side-to side by hand, then the pinion bearings have problems.

 

[Cow_doc.308]

The up and down/ side to side slack is the problem I've got.

If gears were damaged either place wouldn't you expect a good bit of noise on top of vibrations?

 

[XJeepguy]

So I took it to a shop this morning and the mechanic says there is a lot of slack at the rear differential and the tcase. He says he's pretty sure the pinion bearing is bad and probably bad bearings in the tcase. He hasn't pulled it apart to see exactly what all the problem is.

Should I repair what I have, buy a salvage rear end and tcase, or sell the runner and buy another?

No offense to your mech. but I would get a 2nd opinion before buying all that.

 

[Cow_doc.308]

No offense to your mech. but I would get a 2nd opinion before buying all that.

For sure. I've got another guy gonna drive it this evening

 

[Cow_doc.308]

Ok, just an update here.

I called the mechanic told him I was coming to get the runner until I could decide what I wanted to do (and I had to have a ride home!). Anyway I get there and he said that after he dropped the drive shaft he did what Blonde1 did and tightened the nut on the back of the tcase back to torque spec and that got rid of all of the slack there. When I drove it home, 90% of the vibrations were gone. :thumb3:

I still have my rear diff with slack in it and leaking oil. Given what I saw in a youtube video in another thread it looks a lot like my pinion bearing are bad. So, hopefully next weekend, when I'm not on call, I'm going to drop the 3rd member and inspect and repair as needed. Fingers crossed for just needing new bearings.

I had the same issue literally two days ago. The flange output from the transfer case had a quarter inch wobble to it. I dropped the driveshaft and used a 30 mm socket to tighten the staked nut out which got rid of the vibration.

Oh, and one of my technicians volunteered her mechanic husband to help me so I'll have an experienced set of eye to help me out....and access to his tools

 

[XJeepguy]

Sounds a lot better . Pinion bearing shouldn't be that bad .

Ok, just an update here.

I called the mechanic told him I was coming to get the runner until I could decide what I wanted to do (and I had to have a ride home!). Anyway I get there and he said that after he dropped the drive shaft he did what Blonde1 did and tightened the nut on the back of the tcase back to torque spec and that got rid of all of the slack there. When I drove it home, 90% of the vibrations were gone. :thumb3:

I still have my rear diff with slack in it and leaking oil. Given what I saw in a youtube video in another thread it looks a lot like my pinion bearing are bad. So, hopefully next weekend, when I'm not on call, I'm going to drop the 3rd member and inspect and repair as needed. Fingers crossed for just needing new bearings.



Oh, and one of my technicians volunteered her mechanic husband to help me so I'll have an experienced set of eye to help me out....and access to his tools