Help with drive line angle?

[JRSTI]

I have a 1972 K5 with a 6 inch lift and a 700 r4 tranny. My transfer case makes a rattles sound at 40 mph and above. The transfer case output slope is 0 degrees. The axle pinion slope is 19 degress. The drive shaft slope is 20 degrees. Do I need to move the axle pinion up or down and by how manet degrees?

 

[Moody]

http://www.pirate4x4.com/tech/billavista/PR-shaft/index.html

Here is some great reading on the subject......

 

[JRSTI]

I did read that an got lost with all the info. Just need to be pointed in the right direction.

Thanks for the help.

 

[Moody]

Just out of curiosity did you move your engine forward when you did the 700r4 swap? If not, it moves your transfer case back increasing your driveline angle. With 20 degrees difference you would probably have to add shims and try to move your axle back if you have the room. Even with those mods you may not be close enough with a fixed yoke. You might end up having to use a C/V joint in the back. Hope that helps!

 

[Moody]

Sorry, just realized I didn't answer your entire question. You would need to move the pinion down with shims at least 5-8 degrees and move your axle back with a zero rate an inch to inch and a half. Remember, at operating speeds your pinion will want to move up so you have to take that into consideration.

 

[JRSTI]

I did move the transfer case back to fit the 700r4. I also have a Offroad desing shacle flip, so that moved the axle forward an inch.

 

[Moody]

I'm assuming you're using 56's in the back with the flip. The combination of the flip (moves the axle forward) and the transfer case back both increase driveline angle. I'd see about using a zero rate and moving the axle back 1.5" and try some shims and see where your at. You might want to look at a longer rear shackle as well.

 

[Hogback Fabrication]

With that much lift and the shortish wheelbase of K5, the only way you will fix this is with a double cardan (cv) shaft.

The simple fact is that even if you get your angles to match, the operating angles of each joint are simply too steep to eliminate vibration.

It sucks, but that's the way it is.

 

[JRSTI]

Thanks for the help guys.