BonesDT
Elite Explorer
- Joined
- July 12, 2002
- Messages
- 1,066
- Reaction score
- 9
- City, State
- Westchester, NY
- Year, Model & Trim Level
- Red '99 Sport SOHC 4x4
I'm having some major vibration/hum issues.
Recently I installed 4-door leafs. The packs I got had wedge shims on them. The shims came positioned so as to angle the axle pinion downward. I thought this was odd and my I made the amateur mistake of reversing the shim so as to angle the axle upwards thinking this would help relieve some driveshaft angle.
http://www.pirate4x4.com/tech/billavista/PR-shaft/index2.html
1) For driveshafts with a single-cardan u-joint on both ends (as I have), you want the t-case flange and the axle flange to be at the exact same angle (parallel to each other). Since the joints are at the same angle, their elliptical rotational pattern perfectly cancel each other out.
2) For driveshafts with a double-cardan u-joint on the t-case side and a single-cardan on the axle side, the t-case flange angle doesn't matter, but you want the axle pinion to be pointing directly at the t-case flange. The two joints in the double-cardan are naturally at the same angle and cancel each other out, hence the third axle joint needs to be at (almost) zero degrees so as not to vibrate since there isn't another joint for it to cancel out with.
3) There isn't a lot on this, but for driveshafts with multiple double-cardans (on both ends), it's a free for all, but at the expense of a shortened main shaft which cannot tolerate as high angles.
Based on this, I tried to rectify the issue by reversing the shims back to the way they came to try to make the flanges more parellel. I measured the shims to be 2.17 degrees. When I had the shims angling upwards, the difference between the top of the flanges measured 38 1/16" long and the bottom of the flanges measured 37 5/8". After I put the shims back to the stock position, I now have 37 15/16" on top and 37 13/16" on bottom. The axle pinion is pointed up at 4.5 degrees and the t-case is pointed down at 2.5 degrees. I still have the vibe issues, could this small difference still be it??
However, I have never seen any mention about a driveshaft with a double-cardan on the axle end and a single-cardan on the t-case end. It seems to me this kind of driveshaft shouldn't even exist, because it would mean you would have to point the t-case flange directly at the axle, which would be some extreme engine/transmission/t-case angling.
I'm not sure which Explorers came with double-cardan rear driveshafts, but what I do know is my 99 Sport came with a single-cardan and Cardone shows a double-cardan for 95-96 Sports.
Now here's where I'm really confused. The 95-96 Sport driveshaft has a double-cardan on the axle end (or does it?). How can this be??? How do you set-up your pinion angles.
Recently I installed 4-door leafs. The packs I got had wedge shims on them. The shims came positioned so as to angle the axle pinion downward. I thought this was odd and my I made the amateur mistake of reversing the shim so as to angle the axle upwards thinking this would help relieve some driveshaft angle.
http://www.pirate4x4.com/tech/billavista/PR-shaft/index2.html
1) For driveshafts with a single-cardan u-joint on both ends (as I have), you want the t-case flange and the axle flange to be at the exact same angle (parallel to each other). Since the joints are at the same angle, their elliptical rotational pattern perfectly cancel each other out.
2) For driveshafts with a double-cardan u-joint on the t-case side and a single-cardan on the axle side, the t-case flange angle doesn't matter, but you want the axle pinion to be pointing directly at the t-case flange. The two joints in the double-cardan are naturally at the same angle and cancel each other out, hence the third axle joint needs to be at (almost) zero degrees so as not to vibrate since there isn't another joint for it to cancel out with.
3) There isn't a lot on this, but for driveshafts with multiple double-cardans (on both ends), it's a free for all, but at the expense of a shortened main shaft which cannot tolerate as high angles.
Based on this, I tried to rectify the issue by reversing the shims back to the way they came to try to make the flanges more parellel. I measured the shims to be 2.17 degrees. When I had the shims angling upwards, the difference between the top of the flanges measured 38 1/16" long and the bottom of the flanges measured 37 5/8". After I put the shims back to the stock position, I now have 37 15/16" on top and 37 13/16" on bottom. The axle pinion is pointed up at 4.5 degrees and the t-case is pointed down at 2.5 degrees. I still have the vibe issues, could this small difference still be it??
However, I have never seen any mention about a driveshaft with a double-cardan on the axle end and a single-cardan on the t-case end. It seems to me this kind of driveshaft shouldn't even exist, because it would mean you would have to point the t-case flange directly at the axle, which would be some extreme engine/transmission/t-case angling.
I'm not sure which Explorers came with double-cardan rear driveshafts, but what I do know is my 99 Sport came with a single-cardan and Cardone shows a double-cardan for 95-96 Sports.
Now here's where I'm really confused. The 95-96 Sport driveshaft has a double-cardan on the axle end (or does it?). How can this be??? How do you set-up your pinion angles.
