Periodic vibration - unclear if drive line

[ShawninVA]

I just DIY upgraded from stock to OME medium springs and I love the improved ride. Now that the honeymoon period is over, I'm noticing a periodic, faint vibration between 40 and 70 mph that I'd like to get rid of. I'm now obsessing over it, mainly because I am a or mechanic, at best, working on a 285K mi truck and I am paranoid. It's so faint that if I'm talking to someone or have the radio on, I forget about it. My wife and kids did not notice it until I pointed it out.

I can feel the vibration come and go at about 40-45 cycles per minute. It goes away, then gets more intense, peaks, then fades away again. It's very regular. Some more details:

- I installed the OME offset control arm bushings per the instructions, and got an alignment after. The shop said my caster was 0 degrees ?!? I can't figure out why that might be related, but there it is.
- I have regreased my u-joints and put two pumps in the slip yokes. Checked for driveshaft play. Can't detect any (just under the truck, four wheels on ground). BUT I've never replaced the u-joints.
- I do have the typical shift clunk for an 80 at 285K.
- I can't link it to speed OR RPM. It does not go away or change while moving in neutral, or with CDL, or downshift out of overdrive. Yep, now you probably think I'm imagining things.
- I can't feel it in the wheel. I can't feel it in the tranny or 4WD shifter. I feel it in my feet and my butt.
- Does not go away with A/C off.

Speculation, "try this", or thread links are welcome. I'll have some time to play with it this weekend. I had planned to cruise Uwharrie but all the rain makes me think again.

 

[BILT4ME]

Typically vibes like that at those speeds are U-Joints. Especially after a lift, which changes the dynamic area the U-joints have been riding in. They are working a bit harder and are wearing in new areas.

Run them until they get louder or change them out.

 

[ShawninVA]

I'll change them out. I did not think about the wear issue you mention.

 

[inkpot]

I would stsrt by greasing them good and don’t forget to put a little grease in the slipyoke also. It may be just wanting a little love?

 

[ShawninVA]

I would stsrt by greasing them good and don’t forget to put a little grease in the slipyoke also. It may be just wanting a little love?

Yeah, I did both two weeks ago and still have the issue. After so many miles, I wonder if I ought to just replace the u-joints.

 

[baldilocks]

Can you post a couple photos of your axle and drive line from the side just behind the front tires from both sides. Your castor should not be zero with those bushings.

Also measure from center if hub to fender lip so we know how much lift you got from the mediums. Perhaps it was more than advertised if your rig is bone stock.

If your U-joint angles are not correct at both ends, New Joints will soon be vibrating also.

 

[lumbee1]

Install a hazard switch with the 7 pin mod. Remove your front driveshaft and lock your axles with the center diff locker switch (hazard switch). Go for a drive and see if you still have vibrations. If you do, reinstall the front drive shaft and remove the rear drive shaft and go for a drive.



Slee - Pin 7 Mod for CDL (Toyota 80 Series Land Cruiser)
7 Pin Mod

Hazard switch relabel
80 Series CDL SWITCH $30 SHIPPED

 

[ShawninVA]

I'll jump on the photos in the morning.

I have the CDL mod already. While troubleshooting this week, I stopped getting indicator lights and my relay is not making any noise. I'm taking a look at the position sensor tomorrow as well checking the ECU connector. First time I've had this problem after installing the switch a year ago.

 

[inkpot]

Yeah, I did both two weeks ago and still have the issue. After so many miles, I wonder if I ought to just replace the u-joints.

Have you tried changing the phase of the front driveshaft? Rotating the front half of the shaft by 90 degrees MAY quiet the noise created by lifting the rig. Quick and easy test that is free to do. If no improvement then replace the joints. Be sure to use OEM quality parts.

 

[Tools R Us]

... I'm noticing a periodic, faint vibration between 40 and 70 mph ...
I can feel the vibration come and go at about 40-45 cycles per minute. ...

That type of sound can be from low/dry knuckle(s), they should be 1/2 to 3/4 full with moly grease. Confirm by looking in the inspection plug, add as needed to bring it up to level.

 

[ShawninVA]

The weekend got away from me. Finally got a tiny bit of wrenching time tonight. I have not figured out the center diff lock issue. I looked the FSM diagnostic procedure but set that aside since it looked like I needed a few hours.

While changing the oil, I took the control arm pics.

 

[ShawninVA]

I used an inclinometer at work a couple of years ago and might still have it around. Maybe I should check caster myself? The numbers were given to me by Mr. Tire in Durham. I'm not sure I completely trust them.

 

[ShawninVA]

And, the center-to-flare distance for each wheel:

PS Frt 22"
DS Frt 21 5/8"
PS Rear 23 1/8"
DS Rear 22 5/8"

 

[ShawninVA]

Paused everything to look at the CDL issue. Sensors look OK, the relay looks OK. No noise from the actuator. I can't get it to lock up even in low range (no pin 7 mod). I might be adding the diff lock actuator to the list. I suppose dropping the xfer case would be a great time to pull the shafts and change out the ujoints. I have the inclinometer and can get the flange face vs. shaft angles. I assume that is what's needed to check my driveline setup.

@baldilocks Any feedback on the photos and lift heights, above?

 

[baldilocks]

Looks like you have very little suspension lift so your U-joints should still be at reasonable angles. Did you install the taller springs on the driver side. Looks like your rig leaks driver quite a bit.

 

[ShawninVA]

Looks like you have very little suspension lift so your U-joints should still be at reasonable angles. Did you install the taller springs on the driver side. Looks like your rig leaks driver quite a bit.

I got the springs from Slee and followed the US version of the instructions. TBH, I went by label and not by height. So, 3/8 - 1/2" is a lot?

 

[ShawninVA]

After working out the CDL issue, I've done a fair bit of work tracking this down. I've replaced the ujoints with OEM thanks to @beno. I needed them from the looks of the old ones. In the process, I did some of the recommended diagnostics.

It does not occur when driven with CDL on only one driveshaft - front or rear.

It is 100% speed related, not engine. It might be a tad worse under power or coasting but not significantly.

It seems like the vibration moves left to right and I can feel it in the steering wheel. This puzzles me, because if it was isolated to the front axle I should have felt it with CDL+front shaft only. I can't feel it in the tcase shifter, either.

Next steps are checking the knuckles.

After that, assuming no issue with the knuckles, should I change the phase or balance the driveshafts, even if I can't feel it with one shaft?

 

[blkprj80]

If you go out and rock the truck side to side (get mean with it!) at the front, can you feel or hear the bearings moving? Robbie ( @powderpig ) did this to mine and said I needed to service the front axle, which I did. Mine wasn't noisy, but I hadn't driven it much at that point. I had a vibration that I finally got go go away with a double cardan driveshaft. Replacing front driveshaft u-joints didn't help any.

 

[ShawninVA]

If you go out and rock the truck side to side (get mean with it!) at the front, can you feel or hear the bearings moving? Robbie ( @powderpig ) did this to mine and said I needed to service the front axle, which I did. Mine wasn't noisy, but I hadn't driven it much at that point. I had a vibration that I finally got go go away with a double cardan driveshaft. Replacing front driveshaft u-joints didn't help any.

Thanks. How much lift at the time?

 

[blkprj80]

OME 2.5" I think. Heavies in front, Medium in rear.