New Drive Shaft SYE, More Vibes

[skates04]

Well I finally ditched the the t-case drop, and got a Tera SYE kit and a tom woods cv drive shaft, and a set of adjustable uppercontrol arms, I was getting vibes with just the drop above 60mph both Accelerating and Dec. My upper arms came first, and I found my stock arms had shot bushings, so the new arms, helped the ride and got rid of all deceleration viberations, and slightly helped the others, Well since installing the SYE and drive shaft I cant seem to get rid of the viberations and they are worse, At first I did'nt have anything to get my angles So I eyeballed it. Then I used a slope Gauge that came with my Tomwoods shaft and my drive shaft and pinion were dead on 20*, Still getting vibes I lowered my pinion 3* as suggested, and I still get vibes, My control arms are also set exactly even. Any suggestions???? Lower arms are fixed so nothing can be adjusted there, which should'nt really matter. This is all kind of annyoning after dropping all that money on these parts.

[NAILER341]

did you use the first pic to set yours up?

[blkTJ]

the angle at the axle pinyon to driveshaft is 0 to -3 degrees, yes??? (where is this 20 degrees coming from???)

if that is the case the ds needs to be rebalanced.

[skates04]

The drive shaft angle is 20 degree's, and the pinion is 3 degrees less than that (17 degree's) And it is setup just like the top picture

[blkTJ]

the ds needs to be rebalanced.

see above.

{edit}pull out the front driveshaft to eliminate that as a problem, it may need to be balanced as well{/edit}

[goodtimes]

Where are you measuring the pinion angle from? I had the same problem until I talked to Tom Woods (nice guy), He suggested measuring the pinion angle by pulling the diff cover and measuring the rear face of the diff housing, which is exactly 90* (perpendicular) to the pinion. He also told me that I should shoot for 1* below the driveshaft slope, not 3 (as I had initially set it up).

Another place that would be good to measure pinion angle is the front face of the yolk, provided it has not been torn up on the rocks (ears must be flat).

[skates04]

I have been measuring from the rear face of the differential, but with the cover on I guess that could be making a difference, I'll see about measuring off the yoke and see where its at, And then set it to 1 degree less than the drive shaft and see what happens.
Lucas

[cjdirtbiker]

Driveshaft vibes at 60?

If you're just getting vibes at speeds over 60 I would not suspect driveshaft alignment, although it's possible. Normally it will show up off start and at lower speeds once the shaft gets moving and the harmonics get to working, say like 25 to 40mph. It sounds more like tire balance or wheels out of round. We have to trust you can tell the difference between DS speed and wheel speed. If you have aggressive mudders that are really worn and cupped they can show vibes like that too.

I didn't get that fussy measuring mine. It looks pretty straight and there are zero vibes, even at 75mph The tires are another story.

You might check your motor mounts as well. And yeah, I would pull the front to eliminate that as a possibility.

[aston]

If you're sure it's the rear DS remove it and prove yourself right

[skates04]

The tires are brand new goodyear wranglers, and I have access to a wheel balancer and I balanced them my self, the wheels are new as well, and I was getting the same vibes with my old tires, But Im not ruling that out yet. So more info on it, its a pulsing vibration, in about a 3-4 second span it goes from nothing to worse to nothing, I know it was probably a bad idea, but at 65 I put in 4hi and it pretty much went a way, then as soon as I put it back in 2wd it came back, it starts at 60mph and gets slightly worse I go faster, up to 80mph the fourbanger cant get any faster I did hit my front drive shaft pretty hard a while back my boot on the slip joint in the middle got torn off, But there are no missing weights on the drive shaft, from what I can see, I cant tell if its bent just looking at it. So in the morning Im going to take off the front see what happens, then maybe even run it in FWD and see what happens.

[cjdirtbiker]

Tweaked front DS, yep.

>snip
I did hit my front drive shaft pretty hard a while back...
>snip

Uh, gee, there's your problem. It doesn't take much to knock them off center. Just a wee bit will cause vibration.

I was going to mention hitting your DS with a rock but I just naturally figured it was a new DS since we were talking about a new one with SYE. Never thought to consider it could be the front one!!!

Yes, pull the front DS and see if your vibration disappears!

[skates04]

The front drive shaft did it, took it out and no more vibrations, now to get it fixed. If its slightly bent can it be striaghtend?

[igofshn]

It can be retubed.