Hello all,
I recently just did a manual swap on my truck (A518 to NP435) which moved the transfer case up by approx. 4 inches. I got some salvage yard manual driveshafts and the rear fit fine. The front however (15" W-W) seems to short because if i extend it to fit there is very minimal spline contact. I measured and there is only 3.25" total of spline length. That being said how much engagement is needed. Secondly, the front angle is also quite steep (It binds and you cant turn it by hand). What I need to do is change the pinion angle, but could I just clearance the cv for now until i have time to re-shim? Thanks in advance.

 

You never want to change the front pinion angle with shims. It will change the steering angles and cause the truck to handle poorly.

Clearance the "CV" - this is very common and an accepted fix.

As for your spline engagement; you should be fine unless you do some severe off-camber off-roading.

 

Are the shims really that bad? I have some installed that came with my lift and i wouldnt say it handles poorly, I mean it aint no ferrari, but thats because its a 22 year old truck. I also thought that with a CV shaft there should be no angle on the u-joint that connects to the dif? Correct me if I'm wrong.

 

You have a double-cardigan on one end of the front drive shaft and the u-joints at the front and it is very common to "clearance" the pinch-points to allow for more room when flexing.

What size lift do you have?

The only "proper" way to adjust the front pinion angle is by rotating the tubes in the center section. This however is very expensive and time consuming while also not a viable option in 99% of the cases. It is also not recommended to shim the front axle very much as you will introduce negative caster which will cause the truck to wander and drift going down the road.

 

I have a 6" lift on the truck. Drifting and wandering on the road doesnt sound like a fun driving experience so I should probably stay away from shims then. Will clearancing the u-joints cause them to wear faster, as this is my DD and I dont have OD, so the shaft will potentially spin at 2400+ RPM.

 

You won't be grinding the U-joint itself just the area's where they will contact or bind

 

That I understand. I'm still a little nervious about the spline contact though. I'm thinking I may not even have and 1". I'm not at home right now so I can't measure it. Is there a rule of thumb to go by as far as how much spline contact is needed? Thanks for all the help so far.

 

The shaft should have roughly 5" total spline travel: 2" at compression and 3" at extension as a rule of thumb. With 6" lift you may need to have a new drive shaft made or yours lengthened. Now you can buy a spacer (or you could I haven't looked in a long time) that would go between your double-cardigan flange and the transfer case flange. But that would only give you at most an inch.

 

I guess i never measured the spline travel on the "new" ds i got. My old one (20" W-W) only has 3.25" of total travel, I assumed the 15" would be the same, but maybe its not. If the 15" does have 5" of travel then I'm probably alright.