Save 300 to 400 on Driveshaft vibration fix?

After reading a couple of articles on resolving driveshaft vibration it seems I can get away with using shims rather than getting a CV Shaft if I understand it correctly.

After adding my lift kit my shaft has an angle coming down from the transfer case but has vertically no angle at the pinion so the fix, it would seem, would be to shim the pinion down to match the angle at the transfercase. Is this correct?

Also from my reading it appears that the pinion tilts up when driving so I would need to compensate additionally downward when shimming. Also correct?

Now, the question is, if all this is correct, where to get the shims?

Also, the rear leaf springs already have shims attached in some way. Do I need to take these off or just apply the compensating shims?

One more thing, can I (should I) use some washers to adjust the pinion temporarily to test this fix?

Thanks,

Bill

Reply to
William Oliveri
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Excuse me, That's "Virtually no angle" instead of "Vertically no angle" below. In other words, almost straight from the pinion to the the angle at the transfercase.

Bill

Reply to
William Oliveri

Maybe, not in every case however. The shims may help for vibration but they don't compensate for a short shaft (stop giggling). : : After adding my lift kit my shaft has an angle coming down from the transfer : case but has vertically no angle at the pinion so the fix, it would seem, : would be to shim the pinion down to match the angle at the transfercase. Is : this correct?

Ideally you want the angle of the output shaft the same as the pinion. You are correct in your statement. The setup you have right now would be ideal for the SYS/Driveshaft - all of the angle at the output shaft and maybe 1* at the pinon.

: Also from my reading it appears that the pinion tilts up when driving so I : would need to compensate additionally downward when shimming. Also correct?

In therory, yes but I wouldn't bother too much trying to compensate for that. Work with an angle finder and fine tune by the seat of your pants for regular driving.

: Now, the question is, if all this is correct, where to get the shims?

Local spring shops may have an assortment handy. They might let you try a 4* and exchange it for a 3* etc.

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offroad shop wil have them. : Also, the rear leaf springs already have shims attached in some way. Do I : need to take these off or just apply the compensating shims?

You may have shims in there now, I can't tell from where I'm sitting. I would start from the bare spring perch and use one correct shim.

: One more thing, can I (should I) use some washers to adjust the pinion : temporarily to test this fix?

Not without a camcorder handy... I wanna see this! The shims are held onto the spring by the cantering pin which goes through the middle of the shim. If you stacked washers on the pin the only thing you would achieve is the worlds cheapest lift/lowering block (SOA/SUA). If you tried to stack them at the front of the perch, they would shoot across the room as soon as you put weight on the them.

Shackles will also change pinion angle but will affect your amount of lift.

-Brian

Reply to
Cherokee-LTD

Hi,

  1. Drop the tcase xmember 3/4".

  1. Put the Jeep on a level surface with normal load inside.

  2. Use an angle finder on the slip yoke to measure the tcase output shaft angle.

  1. Measure the pinion angle. Back of the diff housing makes a good perpendicular surface for the angle finder.

  2. Subtract your tcase angle from your pinion angle. This is exactly how many degrees you need to drop the pinion. If you round it off, round up to account for axle wrap.

  1. Figure out what your drive shaft angle will be relative to the pinion & tcase once they are parallel. If this relative angle is greater than

15 degrees, you'll have trouble eliminating vibes and your joints will wear quickly.

Beg or borrow shims from local Jeep club/garage or buy new:

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Depending on the depth of the shims, you may also need center pins with longer nubs.

Better yet, cut your spring perches off and re-weld them for precisely the angle you want.

Steve

William Oliveri wrote:

Reply to
Steve

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