Vibrations on the Highway

[EOE_overland]

Just bought an '89 FJ62 three weeks ago. Engine runs good (210K), but I have a consistent vibration starting about 60mph that increases to 70mph (where I stop accelerating). I had a bad axle seal on the front axle; replaced axle seals, knuckle and wheel bearings last week. No change. By the way- thanks to all of you who posted great instructions on front axle rebuilds, hub assembly (PO/mechanic didn't assemble them properly- no damage, though!), and the tips on going with Marlin seals from Cruiser Outfitters- all great! I also had the alignment done and wheel balance checked last week before driving to the Blue Ridge Mountains last weekend. All my work was good, but still the vibration. Still has stock tires with good tread, but doesn't feel like a tire/wheel issue. Any thoughts on what I should look for? I'm going to do the rear wheel bearings in the next week or two, but it feels like (I hate to say it) it's coming from the driveline. I should also say that I changed the oil in the engine, gearboxes, tranny, and transfer 2 weeks ago. All seemed good except the front axle (how I found the seal leak) and I had ATF in the transfer case. I put gear oil back in it. Be gentle I'm a bit of a noob. Had an FJ60 about 10 years ago, but didn't do any work on it myself. Thanks!

 

[Front Range 4x4]

I'm guessing your drive shaft is causing the vibration, what's it condition?

 

[EOE_overland]

It seems ok. No major bangs/scrapes, and doesn't appear to be bent. But is there a reasonable way to check it out for straightness? Anything else in particular I should look for if the shaft is to blame?

 

[cfdlighthouse]

check your u joints....motor and transmission mounts....

bad u joint or broken mounts can allow for a vibration.....

also harmonics can cause the vibration too....the natural disunity of mechanical parts at certian rpms can cause a vibration....

have you checked the fluids in the transfer case and rear axles...

are your front hubs locked

good luck

 

[ferd69]

Sounds like you got bad vibes

I had the same problem. I pulled off my rear driveshaft and checked the U Joints and they were fine. I took the driveshaft to a driveshaft shop and had them balance it. Sure enough it was way off balance. New U-joint and balanced sure made a difference. The ride is so smooth I have to keep my eye on the speedometer I can’t tell when I hit 90’s ++++

Sometimes, you can get rid of driveline vibration by simply rotating the driveshaft 180 degrees and reinstalling.

 

[Front Range 4x4]

It seems ok. No major bangs/s****es, and doesn't appear to be bent. But is there a reasonable way to check it out for straightness? Anything else in particular I should look for if the shaft is to blame?

Sounds like you got bad vibes

I had the same problem. I pulled off my rear driveshaft and checked the U Joints and they were fine. I took the driveshaft to a driveshaft shop and had them balance it. Sure enough it was way off balance. New U-joint and balanced sure made a difference. The ride is so smooth I have to keep my eye on the speedometer I can’t tell when I hit 90’s ++++

Sometimes, you can get rid of driveline vibration by simply rotating the driveshaft 180 degrees and reinstalling.

Like ferd69 said; try rotating the DS 180 first, if that doesn't work bring it to a DS shop. That was the cause of major bad vibes on my 62.

 

[EOE_overland]

Like ferd69 said; try rotating the DS 180 first, if that doesn't work bring it to a DS shop. That was the cause of major bad vibes on my 62.

I'll give the DS rotation a try. Let you know how it goes.

 

[EOE_overland]

Like ferd69 said; try rotating the DS 180 first, if that doesn't work bring it to a DS shop. That was the cause of major bad vibes on my 62.

Bingo! Pulled the DS at lunch. Let it sit in the parts washer to ungunk it. Looks like a counterweight may have broken off in one spot. Local DS shop is too far away today to get it balanced. So I rotated it, and the pulsation at 70mph is less than half what it was at 60mph on the way to work. I was so happy I went 70 the whole way home! I'm going to wait a week (for parts), do the u-joints, then get it balanced. Then all should be well. Thanks guys; great work!
Any idea as to why rotating it helps? It seems to me that and unbalanced shaft is unbalanced in any position?

 

[Front Range 4x4]

Bingo! Pulled the DS at lunch. Let it sit in the parts washer to ungunk it. Looks like a counterweight may have broken off in one spot. Local DS shop is too far away today to get it balanced. So I rotated it, and the pulsation at 70mph is less than half what it was at 60mph on the way to work. I was so happy I went 70 the whole way home! I'm going to wait a week (for parts), do the u-joints, then get it balanced. Then all should be well. Thanks guys; great work!
Any idea as to why rotating it helps? It seems to me that and unbalanced shaft is unbalanced in any position?

My apologies for not being clearer on rotating 180 degrees. What I should have said was separate the slip-yoke from the long end of the DS and reinstall it with the u-joints in alignment (phase).

I snagged someone else pic to illustrate, note the difference shown by the arrows:

 

[Front Range 4x4]

Any idea as to why rotating it helps? It seems to me that and unbalanced shaft is unbalanced in any position?

Oh, what probably helped you was the cleaning, may have been enough junk to throw it further out of balance than just losing the counterweight. Regardless, you have narrowed it down to the DS and saved yourself from replacing other stuff.

 

[EOE_overland]

Yeah, plenty of gunk! Thanks again,
Matt