Driveline and Pinion Angle

I have the drive line with a front driveshaft from the transmission to the CB. Behind the CB, it is connected to a double cardan joint. The DCJ is connected to the rear drive shaft which is connected to the rear pinion flange. The output flange at the transmission measures 87.3 deg down, rear flange on the front driveshaft measures 85.5 deg down and the rear pinion flange measures 83.7 deg up (?)(It is parallel to the others but off-measurement). Do I set it to the angle of the tranny flange or, taking into consideration the DCJ, to the rear flange on the front driveshaft? And how much?

 

I have the drive line with a front driveshaft from the transmission to the CB. Behind the CB, it is connected to a double cardan joint. The DCJ is connected to the rear drive shaft which is connected to the rear pinion flange. The output flange at the transmission measures 87.3 deg down, rear flange on the front driveshaft measures 85.5 deg down and the rear pinion flange measures 83.7 deg up (?)(It is parallel to the others but off-measurement). Do I set it to the angle of the tranny flange or, taking into consideration the DCJ, to the rear flange on the front driveshaft? And how much?

 

I have the drive line with a front driveshaft from the transmission to the CB. Behind the CB, it is connected to a double cardan joint. The DCJ is connected to the rear drive shaft which is connected to the rear pinion flange. The output flange at the transmission measures 87.3 deg down, rear flange on the front driveshaft measures 85.5 deg down and the rear pinion flange measures 83.7 deg up (?)(It is parallel to the others but off-measurement). Do I set it to the angle of the tranny flange or, taking into consideration the DCJ, to the rear flange on the front driveshaft? And how much?

 

If you are trying to get rid of driveline vibrations, point the rear pinion directly at the carrier bearing. The DC can handle all of the angle difference between the two halves of the driveshaft, as the two u joints in the DC make it “self cancelling”. The u joint at the transmission or transfer case has no opposing joint to cancel the angle, therefore you want to keep the angle there to a minimum (i.e. don’t use a CB spacer). Likewise, the u joint at the rear diff will last longer and run more smoothly if you minimize the angle there as well.

 

So you are saying shim the rear axle so the flange is at 85.5 deg?

 

Mine is opposite of that. Trans connects to drive shaft. Drive shaft goes through carrier bearing and connects to double cardan joint. Second driveshaft connects to other end of DCJ and then to pinion on transfer case.

 

@drr
???

 

This is how I fixed my drive line angles on my 1978 Land Cruiser FJ40.

To Determine the angle difference you will need a magnetic angle finder, from Lowe's for under $10

Pinion flange angle reading



E-brake angle reading


Do the math


Use shims to correct the angle


Place shims above leaf springs and you're done

 

I'm not quite clear on where you're measuring the 85.5 degrees, is that right in front of the carrier bearing on the front half of the rear driveshaft?
You basically want to make the rear pinion flange as close to 90 degrees to the rear half of the driveshaft as possible. So if you stick your angle finder on the driveshaft, and then against the flange at the rear diff, you want those numbers to be either + or - 90 degrees from each other. This will minimize the included angle at the rear u joint, which is what is causing the vibration.

 

90 deg less 1-2 deg to account for axle wrap correct?

 

Well, you should probably try to eliminate any axle wrap as much as possible. Generally that will wear out your leaf springs faster, and put additional strain on driveline components.
Your pinion will tend to lift up under moderate to hard acceleration, so accounting for some lift so the u joint doesn't bind is probably a good idea. Also, it's unlikely that you'll get the pinion pointed directly along the axis of the drive shaft using angled leaf springs shims, so as long as you err on the side of keeping the pinion slightly below the driveshaft, you should be good.

 

Rear pinion flange should point right at the center support bearing where the double cardan joint is.

 

And if it doesn't, what then and why?

 

Ok im confused after reading this. But your drive shaft angle should be no more then 1-3 degrees. Which you can just get a app on your whome and measure really quick. If its more then that and you are getting vibration you might any to look into shims on the leafs or carrier bearing drop (this is for the rear)
Same measurement for the front but idk how to correct that