So i installed a new coast frint DS this weekend, anyone think the difference between the pinion angle and the DS angle of about 1.5* will cause a vibration?

 

My Coast front driveshaft causes vibrations also. My buddy with a JE Reel says his does the same so I have to write it off as the design.

I've heard you can adjust the pinion up to be more inline with the transfer but there's a trade off with it impacting the caster.

I guess it all depends on how bad it is. Mines noticeable but not too bad. It's a rumble that starts around 70 and will progressively get worse as speed increases.

 

I just installed mine over the weekend and so far no issues (knock on wood)

 

Too much vibration will blow up your transfer case on a road trip. I have seen this happen twice. I would correct the angle as much as you can to reduce the vibration while keeping your castor manageable.

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I think I'm at 4 1/2* on the pinion so I guess I have a little more room to spare for adjustment. Also, I'm getting re-geared from 5.38 to 5.13 so that should bring the rpm count down a little. I am just wondering how folks with 4" of lift make this work? Do they push the pinion angle to 6 and it works out? Since I dd mine and drive it to where I wheel which usually is 3hr min drive I don't want to risk blowing up txfr case. Maybe I should move to shorter lift like 3" or 2.5".

 

On the contrary, having the 5.38-5.13 gearing will actually amplify what you are experiencing. The DS will be spinning much faster with those gearing. If you do a search, the exploding T cases are majority of the jeeps that regeared to 5.13s and higher

 

Maybe you misunderstood. I'm already geared at 5.38 and thus i have much higher rpms. I plan on getting re-geared to 5.13 for other reasons but it includes the desire to run highway speeds at a lower rpm.

 

Gotcha, yes I misunderstood. Others have adjusted their caster to under 4 degrees (around 3.2-3.4) which seem to reduce the vibration....

If that doesnt work and its hard to find a happy medium to reducing the vibration and driveability, Other options I have seen were to:

1)Remove front drive shaft on long trips.
2)Get manual lock out hubs
3)Get aftermarket axles that have been designed for it.

 

When there is a double cardan on the t-case end of the drive shaft, and a single cardan on the pinion end, the pinion axis has to be as close to the drive shaft axis as possible, preferably within a couple degrees.

Another thing to consider is how the drive shaft is mounted to the t-case.
One method places the double cardan closer to the t-case than the other. Closer is safer.

A couple years ago, there was a lot of forum traffic about exploding t-cases.
The common items on all of them were:
Lifted
Re-geared
Double cardan at the t-case, single at the pinion
More than a couple degrees misalignment between the pinion and drive shaft
Vibration could be felt
Highway speed
KABOOM!!

 

I have a few of those common items. As far as the dbl cardan mounting - I'm not sure mine could get any closer. Now for the common items (lifted, re-geared, dbl and sngl cardan joints, vibration I think, hwy speed) I can check those. Damn, looks like I'm going to have to pull it to confirm the vibration is indeed from the front.