Driveshaft angles

[Jason7121]

Hi everyone I have a question regarding Driveline angles. My truck is a 71 c10 short bed with Ls and 4l60e with trailing arms in rear. I used cpp tubular transmission crossmember. My trans is 6 degrees down so I put my rear pinion yoke 6 degrees up. I don't have any major vibration but the angles just don't look right. When you look at driveline out of trans it goes upward instead of downward. Anyone have pictures or experience with this on your c10. Thanks for any help.

[Jason7121]

Mine is like this

[Rufas]

I understand what you are going through. My 700R trans is 6.3 down and the pinion is 6.3 up. Is your truck lowered? That will make a difference. With the air out of the bags I have the same as you. With the driveshaft going up to the pinion. With the air maxed out there is a slight slope down to the pinion.

That said I haven't driven it yet to see what happens.

[Jason7121]

Mine is static dripped 4/6 no air ride so my measurements were at true ride height

[Robznob11]

Mine are like that but, my question is ....is that 6* down with a gauge or 6* total with drive shaft angle figure in? If it is 6 down with gauge and the shaft is going up like that then your toatal angle is even more. If that were the case i would raise the tranny as much as i could for 3* down or less and then lower the pinion to match. If you leave it at 6* down it would not hurt to drop the pinion down to 4* up....it will try to raise as you apply tq and the pinion tries to climb the ring gear. It is a standard practice to run your pinion 2* down as compared to the tranny for that reason. Many may debate and say not so unless its a leaf spring truck , but i assure you there is some give even in the truck arm suspension.

[Jason7121]

Yeah trans is 6 down when measured at u joint cap on slip yoke and 6 up on u joint at rear pinion yoke

[Robznob11]

I would at minimum try to raise the tranny and lower the pinion to minimize the compounded angle. I did that with mine and have had no issues with 550+ hp

[Robznob11]

My tranny is at 3* down and my pinion is at 2* up

[Jason7121]

I'll try and raise trans looks like I can raise it maybe 1 1/2 " before it hits floor board

[Jason7121]

Thanks for the help. Did you measure yours on the ujoint caps as well

[Robznob11]

Thats a bunch. On mine i cut 1/2 aluminum plate for spacers under the tranny mount. I rhink think it was a little over 1* for every 1/2* . Be sure you set it up at ride hight with full weight on tires with a level surface. I put mine on level ground with 8" boxes under the tires. That way i could make mesurements and adjustments but still simulate natural ride hight. Make sure tire psi and all is good to. Its the little things that get people messed up...like trying to set it to fram etc....its all about ride hight with actual running gear on the truck.

[Robznob11]

I think i used the shaft on the tranny w/ shaft out and a flat on the pinion. Just look close at the measurement spot, because there are spots that are machined at an angle and will give you false mesurements. Common sense will steer you stright here lol. Its been a couple years since i set mine so i dont remember on the rear.

[Jason7121]

Ok I have Jack stands under front control arms and Jack stands on the trailing arms under the rear coils

[Robznob11]

I would do blocks under the tires expecially if you run staggered wheels and tires. When I did mine i read alot of literature on it including one from a fellow who was a chassies builder who recomended this procedure. Now....In my mind I could not see how that would change the relationship of the u joints much as long ad you had the sprung weight on it like you do.....but in the end I figured it was eaisy to get boxes and left no question of it being wrong ...and just did it. I have had 0 issues, no vibration, no noise

[Jason7121]

I'll try and find some blocks and make sure it's at ride height

[Robznob11]

Set the e brake, cauck the wheels. I pulled the drive shaft and let it roll off once!

[Jason7121]

I have done that too haha. Thanks again I think I'll measure off the caps and leave drive shaft in. But in neutral so I can make sure yokes are level .

[geezer#99]

While you need your pinion angle to be the same as the tranny output, you need to also measure your driveshaft angle to determine the operating angles of your u-joints. Look here for some info on that.
https://www.drivelinesnw.com/part-tr...ngle-problems/

If your angles are in spec just leave it alone.

[Jason7121]

Thanks for the link it should help

[Jason7121]

This weekend I raised the trans got it to 4 degrees down. I took out shims in rear and got rear pinion to 3 degrees up. Haven't driven it yet but angle looks better.