I need a favor from one of ya'll with a liftkit.

[OrangeCrush]

Is there anyway possible someone could get a picture of the pinion angles on the front and rear driveshafts. (front and rear on both)

When I put the Fabtech lift on over a year ago, I had a vibration. As many of you know, I went through 3 or 4 driveshafts in an attempt to fix this. Finally a 3.5" aluminum driveshaft seemed to pretty well cure the problem. It still had a very minor vibration but I was able to live with it.

A few weeks ago, I got a real bad vibration. I took the driveshaft in and the guy said it was warped/bent towards the end. He said that the kind of bend in it usually comes from too much torque. Well, obviously with the stock 6.0, that isn't the case. (I haven't been offroad forever)

The driveshaft place straightens (I don't know how that would be possible) and balances my aluminum driveshaft. The vibration is still the same.

He insists that because it's a harmonic style vibration that the pinion angle is off and not the driveshaft.

My problem with his theory is that, granted if the pinion angle was off, it was next to perfect before the driveshaft got bent. If the driveshaft was put back in the exact same condition as it was before it got bent (straight and balanced), I should at least be as good as I was before, right? Doesn't that make sense since the pinion angle hasn't changed.

Anyway, agreeing that the pinion angle might be off, I took the crossmember for the back of the trans and slotted the holes to drop the transmission about 3/8" of an inch. The vibration decreased significantly.

In the meantime, he made me another driveshaft (this one in steel) and when I put it in, the vibration again decreased significantly. (that tells me that if the vibration decreased, obviously there was still something bent in the other driveshaft)

Anyways, the truck is much better but still has a minor vibration, I would like to see pics of other H2's pinion angles. I want to compare to mine.

So if ya'll don't mind... I need some pics. (actually, it may not be a bad idea to see pics of a stock H2 to see how far the angles deviate from the factory)


Thanks,

Mark

[PARAGON]

I don't know, but after reading all of this. It sounds more like there is something going on with the setup of the rearend. Since you bent the shock also.

Bending the shock should be a good indicator that you might have the rear end off somehow.

[OrangeCrush]

Paragon,

Honestly, I think the bent shock is just a coincidence. It's probably from lifting the truck up on the lift and having the wheels hanging.

I've got more than 20K miles on the lift and it just happened. Not saying it can't be related, I just don't think it is.

Mark

[OrangeCrush]

Phil,

Thanks for the pics. Your rear end looks lower than mine. (of course you are older so it probably sags a little more... :giggling:

Seriously, I've adjusted the pinion angle up, down and around, it doesn't seem to make a difference.

Here's a few pics of what it looks like now. (At this moment, there is a 1" spacer on top of the trans mount to raise the trans)

http://i49.photobucket.com/albums/f279/orangecrush03/HUMMER009.jpg
http://i49.photobucket.com/albums/f279/orangecrush03/HUMMER006.jpg
http://i49.photobucket.com/albums/f279/orangecrush03/HUMMER005.jpg
http://i49.photobucket.com/albums/f279/orangecrush03/HUMMER004.jpg

Other than the fact that I temporarily have a 1" spacer lifting the rear of the trans, the only difference is your pinion angle looks smaller.

I'm at my wits end and really have no more suggestions.

:confused:

Mark

[OrangeCrush]

Your rear shaft at the the t-case looks to be at much more of an engle than mine. Mine is a bit of angle, but not as much as yours, I'll see if I can get a pic tomorrow from the same angle you took yours.

Using a cv based rear drive shaft may be the next thing to try.

Well remember, at the time of the pic, I had a 1" spacer raising the back of the trans.... thus increasing the pinion angle for the rear diff and trans.

I tried a series of different angles to see if a change would make a difference.

I like the idea of a CV joint based driveshaft. That may cure my problem.

Mark

[PARAGON]

Well remember, at the time of the pic, I had a 1" spacer raising the back of the trans.... thus increasing the pinion angle for the rear diff and trans.

I tried a series of different angles to see if a change would make a difference.

I like the idea of a CV joint based driveshaft. That may cure my problem.

MarkWhy the spacer?

Is your tranny and t-case angled up to the rear? It might just be the camera but it appears that the output shaft angles up.

[DRTYFN]

Those look like the undersides of Tahoes.:jump:X17

[OrangeCrush]

Why the spacer?

Is your tranny and t-case angled up to the rear? It might just be the camera but it appears that the output shaft angles up.

The spacer was to increase the pinion angle. I tried different settings. eg. dropping the rear of the trans, raising it, lowering the front diff, raising it... etc, etc.

Mark

[PARAGON]

gotcha, just making sure.

I still say comb over the track bars and panhard bar to make sure no movement took place at somepoint.

After that, through up your hands in frustration

[OrangeCrush]

gotcha, just making sure.

I still say comb over the track bars and panhard bar to make sure no movement took place at somepoint.

After that, through up your hands in frustration

Yeah, when I took the pic, it was still in there. In fact, I was in the process of removing it and if you look this pic, you can see that the nuts are loose. I started taking it off but thought I would take the pics first.
http://i49.photobucket.com/albums/f279/orangecrush03/HUMMER008.jpg

At the bottom of the pic, you can't see it but the two bolts in the crossmember are sitting in slotted holes. They are in the "up" (normal) position. I slotted them to lower the whole assy just to see if that would change anything.

Thanks,

Mark