Drive Shaft Vibrations Solved Step-by-Step

With CB & no rear shims my measurements were:
a. Zero your angle gauge against the back of the transfer case, up to the right (under the truck facing forward) against that nice flat place with the two holes. (photo #2 and photo #3) 0°

b. Measure your first driveshaft angle by placing the gauge underneath the first driveshaft, keeping clear of any mud, stickers, etc. My gauge is magnetic so I flipped it over and hung it upside down. I messed with it a bit to get it perfectly in line with the driveshaft and perfectly underneath (by perfectly I mean I randomly wiggled it around until it came up with the most consistent number). This is your first measurement of three, write it down somewhere, and represents the angle of the first shaft as it comes out of your transfer case. (photo #4)5.5°

c. Take your next measurement underneath the rear (second half) of your driveshaft, after the carrier bearing. I took mine next to the rear differential, again keeping clear of stickers, weights, etc, and wiggling it until I had a consistent reading. This is your second of three measurements, write it down, and represents the angle of your rear half driveshaft as it relates again to the transfer case. (photo #5)5.5°

d. For the third and final measurement, you’ll need to re-calibrate your angle gauge. On mine, I left the gauge where it was, hanging by its magnets under the rear driveshaft, and pressed and released the Calibrate button a few times until the gauge, when hanging under the rear driveshaft, read zero. (photo #6) Then locate the nice flat area up against your rear axle housing, next to the rear differential case. Make sure it’s fairly free of mud etc. (photo #7) Then place your gauge (after zero-ing it out on the rear driveshaft) up against this flat part of your rear axle. I found a nice spot just above the molded line (in red) and next to the diff housing bolts (tip of arrow). This is your third and final measurement, write it down also, and represents the angle at which your rear driveshaft comes out of your rear differential. (photo #8)1°

I'll check my measurements w/no CB & 3° shim ASAP.

 

Current measurements with 3* degree shim and no CB drop:
Front DS 4.7*
Rear DS 4.4*
Rear pinion .3*
I should be vibe free according to these numbers, correct?

 

With these #'s I would hope so. Are the shafts in line, have you run a string line on them?

 

I have not ran a line but I will. If I do, & it's true, what's my next step? Can these shafts be mounted out of phase? On my LC, they had to be mounted out of phase but IDK enough about the d-shafts yet. I'm @ a loss as I should've been vibe free. I've greased the u-joints & shaft splines hoping they were just dry but that didn't help (I haven't had the truck long).

 

I agree you should be vibe free. Your angles are good. I can only think of a worn/defective item. Like a bad u joint, CB, transmission mount, rear axle bearings. You might need professional help by going to a driveline shop. They are generally good at figuring this out. Keep us posted.

 

If one of these were bad, wouldn't I notice vibes @ other times besides ONLY ~5 to ~14mph?

 

Diagnosing vibes can be very difficult. It sounds like you bought the truck with the vibrations. That makes it even harder since you don't have a baseline from before the lift.

 

It was bone stock when I bought it in Feb. 2018. I've done everything to it. It had a vibe before the lift but I'm not sure if it was the bad tires on it or not. It vibrated a whole lot more before I put new tires on it, which happened to be the same time I put the lift on it.
I hate to do it but I guess I'll wait until one of the u-joints shits the bed then replace all 3 rear u-joints & CB. Or save up for a DC one piece shaft.

 

Thanks for the clarification. I have read that others had to get their tires rebalance more than once to fix vibrations. Check with your tire shop. Too bad the vibration didn't get fixed by dealer before mods went on.

 

I'm sure it's not the tires as this is the 2nd set I've had since replacing the bad ones that were on it when I bought it. Long story about the tires lol.

 

I’ve got the same issue, but at 1500 rpm. Took mine to Pablo at Tandem in Ft Worth and he ran all the calcs. I’m still thinking double cardan.

 

@MolonLabeTaco, went back by Tandem today. Since Pablo adjusted the shackles on my OME leafs, the vibe was better and then got bad again. Next step is to replace the bushings in the shackles or go with a different shackle. My vibe didn’t start until about 10k miles ago. Goes along with the theory that something got worn. I’m at about 50k on the lift.

 

do yourself a favor, put a camera under the truck, you especially supercharged are likely going to be appalled at how much axle wrap you have and subsequent HUUUUGE angle changes at the pinion

Unfortunatly there is not much you can do to combat this other than a traction bar or something like a double cardan at the center which helps with the fact you wont have to properly phase angles between the two rear most joints.

 

Running OME springs with all the overloads. You think it still wraps? If it does it’s about to get worse. New headers, high flow cats, snout cutter, and a smaller pulley are sitting in the garage.

 

A shop I use recently installed the weld-on version and wasn’t real impressed. Maybe bolt-on is better.

 

Checked back this pm with my shop/mechanic. He expressed additional negativity about the product and quality.

 

Guaranteed to still have wrap, mount a camera real quick and take her for a spin.

Dont even bother with weld on or bolt on.... I have the weld on budbuilt one and its absolute TRASH. Had to modify and clock the rear bracket and mount the upper axle mount outside of the bracket just to clear the stock exhaust on my 2013, had to replace the rear standard poly joints with proper hard heims to eliminate flex, had to modify for clearance the front shackle mount to clear the body and mount properly to the cross member.

If you want a traction bar like that one can be built so much better.

Oh and to top it off i still have vibes, and by nature of how suspension cycles and what the traction bar does, if the truck is loaded down i get high speed vibes.

At this point im pretty much at a double cardan joint at the center is the only answer, or REALLY REALLY stiff rear springs to get rid of axle wrap.... but id like my ride to be nice.

 

yeah there is NO way id ever buy the bolt on traction bar. Those studs that hold the 3rd member in are NOT meant for those kind of forces.


Airbags could help with load, but wont help with axle wrap.

 

Finally got to measure with the new angle finder...my numbers don't look too bad, zeroed on the transfer case I got 3.8 first shaft, 4.6 second shaft, zeroed again and got 0.4 at diff. Currently have two washers at Carrier bearing and 2.5 degree shims. Any suggestions which to adjust?

 

If that 0.4 at the diff is correct it is way off from the ideal shown in Fig. 10 of the infamous Spicer diagram. You might want to take a peek a my comments in another recent thread on the matter starting with Post #4 here: https://www.tacomaworld.com/threads/drive-line-angles-peer-review-requested.555083/