How to adjust driveshaft angle.

65 CJ5 wihich now has a D44 rear and a D20 transfer case. Have had new clutch and pressure plate installed. Transmission torn down and inspected. D20 transfer case inspected, new intermediate shaft installed. New u-joints. Still have some driveline noise when coasting. I have searched through existing posts and suspect that may need to check driveshaft angle. My question is, if the angle is off, how do you change/adjust the angle? With my setup, what is the appropriate angle?

Thanks

Ross
65 CJ5 Tuxedo Park Mk IV

 

http://www.4xshaft.com/

Tom Wood has a pretty good tutorial here on how to check angles. You need to know what you have to know where you need to go. I try and keep U-joint angles less than 3 degrees different. The closer to equal the better and the shorter the shaft the less forgiving they are to unequal angles. Unequal angles=vibrations. I've had some that were fine with 2-3* different and some that vibrated with 1 1/2* difference. Each vehicle is a little different. To adjust you may have to angle down the transfer case output, angle up the rear axle pinion, a combination of both, or worst case have a driveshaft with a double cardan joint (sometimes erroneously called a cv joint) built and angle up the rear axle pinion. This will require a new transfer case rear output yoke.


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First, are you sure the vibration is from the driveshaft? A loose or bad pinion bearing will also cause your symptoms. Second, if you do lower the cross member, check your fan clearence before your fire it up. A double cardan joint is the preferable way of dealing with this as it doesn't alter the ground clearence or cause the potential fan problem.

 

Thanks guys...good info. Yes, I was thinking about the pinion bearing as well....I can't detect any side to side movement, but I have not pulled and inspected yet. This is not really a vibration, but a rattly noise during coast and higher rpm acceleration.

 

Usually driveline vibrations caused by u-joint angle issues show up in high gear under "float" conditions. In other words that sweet spot when neither accelerating nor decelerating and there is minimal if any load on the drivetrain.


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I put a D30 front axle in my '56, and used McRuff's spring plates and wedges. I don't have the drivetrain installed, but I can see that the angle from the D30 yoke to the T-case is going to be quite extreme. Is this normal when a D30 is put into an ECJ5? Kinda has me wringing my hands.

 

Yes, you can get a pretty big angle at the transfercase but with a little lift, it wouldn't make any difference whether the axle was a 25, 27, 30, or 44. Again, the solution is another double cardan joint but that isn't going to likely fit with a factory V6 and the SM420 guys will also have a bit of a fit problem. Dropping the cross member to get a better angle on the rear driveshaft only acerbates an adverse front driveshaft angle.