BII Driveshaft Vibrations

[BlackBII]

So....I've got about 5" of lift on the BII, and I'm having some serious drivehsaft vibrations that I cannot get rid of. This is the third BII I've had with this much lift, but it's the first one with any problems....

I've got a single carden driveshaft, I have the transfercase and pinion flanges parralell, at the same angle, the u joints are nice and tight...I'm baffled.

On the highway, above 55mph, it vibrates the tranny and t case, and I can feel it in my feet. From about 35mph and down, it sounds like I have cards in my spokes on a bicycle...And I know for a fact it's the driveshaft, and not the tranny, tcase or rear end.

 

[BlackBII]

Bump!

 

[Totalled]

Single cardan...? You mean like this:

Or a single joint shaft like this:

If you have the top shaft, (a double cardan) the diff is supposeed to point at the t-case inline with the driveshaft.

If you have a single u-joint shaft, you are probably at the angular operational limits of the joints and need to swap to a double cardan shaft. (the top one)

I have a single joint shaft, and 5" of lift, and I get a little vibe at those speeds. I also have a C4 trans so my driveshaft is likely longer than yours, and thus the angles are less... so I can get away with it.

 

[Bubba Bob]

Assuming the angle isn't enough to bind the u-joints, remove the shaft and have it balanced.


Also, Ive actually installed U-joints TOO tight before and caused some tough vibrations. I'm not sure if they would have eventually worked themselves loose or not - Got that sucker back on the vise quick.

 

[4x4junkie]

Agreed on the double-cardan driveshaft. These things are short enough a DC shaft is pretty much mandatory with any lift.

The "cards in the bicycle spokes" part sounds more like a bad u-joint or something wrapped up in the driveshaft though

 

[BlackBII]

I have the single joint shaft.

I figured it was time to hunt down a double carden, but I have run that same shaft and the same lift with no problems, so I was a little

The "cards in the bicycle spokes" part sounds more like a bad u-joint or something wrapped up in the driveshaft though

Yeah, That's what I am thinking, but there is not...

This has been puzzling me for about a month now, I've swapped driveshafts, messed with the pinion angle, made sure it wasn't the tranny/t case....driving me crazy!


I'm going to go find a DC shaft. Thanks brotha's!

 

[BlackBII]

Update:

DC shaft took care of all the issues. Thanks guys!

I used a front 1354 output yoke on the back of the TC, and used a front BII shaft shortented about an inch and a half. Works like a charm!

 

[4x4junkie]

No problem. Glad to hear you got it fixed