Low vibration at 60-70mph (3 Viewers)

[Super77]

I’m getting a very low-pitched rumbling vibration between 60 and about 70 mph in 2WD. Anything below or above that speed and it fades out. Been there for a while, but suddenly feels like it’s gotten a little worse.

Let off the gas and put it into neutral, no vibration. Only happens when the whole drivetrain is engaged and under power, so my guess is that it’s neither the engine nor the wheels. Any troubleshooting tips? Out of balance prop shaft?

 

[HemiAlex]

Have you checked if your rear Outputshaft bearing is loose?

Push up and down on the front of the rear driveshaft with your hand from 12 to 6. If it wiggles, you’ve got a problem.

 

[ntdb]

Make sure all of your driveshaft bolts are there and tight. From personal experience.

 

[cps432]

If it’s not your driveshaft it’s your differential carrier bearings and pinion bearing. Luckily, the third member comes out with a minimal amount of work and persuasion and can be swapped just as easily.

Do this: at the pinion flange where the driveshaft bolts up to the diff, see how much lateral play there is. You may need to drop the drive shaft on that end to really get a good idea of how much it’s moving. You should feel the gear lash which is rotational and that’s normal. But if you can move the flange from side to side, up and down, or in and out then you need to rebuild that diff.

If that’s not something you’re able to tackle call cruiseroutfitters. They rebuild diffs and ship them in 5 gallon buckets. It’ll take you an hour to drop it and reinstall the new one. I think the baseline cost is around $600 for a single diff. When you’re done with the job you ship the old unit back to them for a core charge refund.

Alternately, in a pinch, you can swap the front and rear diffs. Usually the front diff is practically brand new since it only turns in 4wd.

If you wanted to re-gear or add lockers to the diffs now would be a good time to do it and cruiseroutfitters can hook you up with all that stuff too.

 

[cps432]

Additionally, you ought to check for the same play in the transfer case output flange. They can both go out and present the same problems. I had an awful noise that I lived with for years until I finally swapped the diffs. That helped tremendously, but the bulk of the wear and tear was in the idler shaft and output bearings in the transfer case. A rebuild fixed all those sloppy noises.

 

[Seth S]

Put some fresh grease in your drive shaft joints and see if it gets better

 

[OSS]

-

 

[poptart]

Put some fresh grease in your drive shaft joints and see if it gets better

Start with this.

 

[Super77]

Thanks for the responses so far. About a year and a half ago, I started to notice a little grumbling in (what I thought was) the third member. At that point I tightened up all the driveshaft bolts, re-greased the expansion joint and U-joints in the driveshaft, and checked the pinion and output shaft bearings for play. None that I could find, but I did suspect that the 3rd member pinion bearing was the source of the grumble.

Around that time I had Torfab rebuild my transfer case, so I doubt the problem is there. I think they know how to do the job right.

Years ago when I had a 40 but lacked the money or sense to take care of it, I recall the drive shaft grenaded itself as a result of a long-neglected U-joint. Started with the same noise I’m hearing now.

 

[1911]

Years ago when I had a 40 but lacked the money or sense to take care of it, I recall the drive shaft grenaded itself as a result of a long-neglected U-joint. Started with the same noise I’m hearing now.

Bad u-joint would be my 1st suspicion. If your truck is lifted, and the working angles of both u-joints are not (close to) equal and opposite, you will get a vibration in a certain rpm range. Over time, that will wear out the u-joints faster than otherwise.

 

[4runner2FJ60]

Same as all above, I had U-joints go out on my 4runner more than once until I had the rear shimmed. It started happening after the 4" lift I put on it. Also when I first got my 60, it would do the same vibration thing over 35mph. I went under to check and not only was the shaft loose with play in the rear, there was an entire bolt missing and 2 others where loose enough to turn by hand! I'm glad it didn't let go.

 

[Super77]

Not lifted as in ‘Bro-dozer lifted’ but I did install a light/medium OME suspension a couple of years ago, and I’m about to add a AAL. I’m actually in the process of baselining the stance against the factory dimensions to figure out IF it’s lifted. When I got the truck it was dragging ass so bad I can’t tell if did more than just put back the original height. I’ll check the u-joints and bearing play while I’m down there.

Is there such a thing as a drive shaft getting out of balance, like a wheel? I noticed mine has a weight tacked on, presumably to true it at the factory.

 

[poptart]

Yeah drive shafts need to get balanced occasionally. If you think it’s that I’d just pull the drive shaft and take it to a shop and have them replace the u-joints and spin it up and check it for balance. Would be a good time to check the rear pinion for play as well like you said.

 

[Rokketz]

Have you checked if your rear Outputshaft bearing is loose?

Push up and down on the front of the rear driveshaft with your hand from 12 to 6. If it wiggles, you’ve got a problem.

i just got a 60 ('85) and noticed some vibrations at 62-65 and beyond mph in 4th gear...im my research here i came across your post and checked the vertical play at the front end of the rear drive shaft..... i have maybe 1mm or 1/2mm play...should there be ZERO play? if thats my issue is it a total rebuild to solve or is it simpler that that? thanks in advance. FWIW i greased all zerks on the front and rear shafts and while that lessened it a bit its still there

 

[OSS]

There should be zero play.
But make sure it’s not the U-joint that’s loose.

 

[Rokketz]

There should be zero play.
But make sure it’s not the U-joint that’s loose.

I joint was good. I greased all the joint too but no play in the joint. Just a tiny bit of movement when I pressed upwards on the bottom of the driveshaft

 

[4runner2FJ60]

I am sure you checked if you did the check for play, but mine would vibrate like crazy when I first got it until a friend was riding in it and ask why it did that between 35 - 45 mph only. I got home and crawled under to find the PO or someone reattached my rear drive shaft with three bolts, only one of which was tight! Yes there was a ton of play. I can't believe it drove as good as it did!

 

[cps432]

I joint was good. I greased all the joint too but no play in the joint. Just a tiny bit of movement when I pressed upwards on the bottom of the driveshaft

Are you checking the pinion and transfer case output flange? The driveshaft should flex just a bit, but the flanges at either end should be 100% solid. If you can move the flange up, down, left, right, in, or out then you have bearings to replace at the very least.

 

[Rokketz]

Are you checking the pinion and transfer case output flange? The driveshaft should flex just a bit, but the flanges at either end should be 100% solid. If you can move the flange up, down, left, right, in, or out then you have bearings to replace at the very least.

pinion side is solid, no movement, the Tcase side there is a slight movement, not much but some....not like the pinion side.

 

[cps432]

pinion side is solid, no movement, the Tcase side there is a slight movement, not much but some....not like the pinion side.

Is there any oil leaking around the transfer case? It might be time for an overhaul.