Transfer case angle for drive shaft angle ????

[1946CJ2]

I have a 4.3/sm420/dana 300 (clocked half way up) on my 48 stretched willys build. Front drive shaft will be approx 31 inches and the rear should be around 35 inches (101 inch wheel base). I am trying to reset my angle for running gear. If I have the rear yoke at 3* down, my front yoke is at o*. I would like to drop the angle of the rear yoke a little more, but this would then increase the front yolk * (to point up) some.

My question: should the front transfer case yoke ever point up past o* to get the rear yoke to point down? Or should I keep the transfer case front yoke at 0* and set my diff yoke at 0*. This would give me a front drive line angle of just under 20*.

[rockbuggy84]

Negative front is real common due to droppin cases to correct for rear shaft. I personally would leave it alone and not drop the t-case, unless you are maxing drive shafts at full drop or have vibes in the rear and are not using a cv style shaft.

[WallyP226]

Isn't pinion angle dependent upon the type of drive shaft you intend to run?

If your sticking with a traditional U joint on each end, then the pinion angle needs to be paralell.

If your going to a double carden or CV style joint, then the pinion needs to point at the drive shaft.

Many times if the knuckles are alread burned on, if the pinion angle is within a few degrees (2-3), people shoot for the appropriate caster.

Wally

[1946CJ2]

The front axle I have to cut and turn. I plan on using a regular drive line.

the rear may have to use a cv.

If I have a neg front * (up) on the transfer case, what should I set the front axle yoke at (0*)? (front axle is a dana 44)

[WallyP226]

If your going to use a single carden joint, the joint needs to operate within 5-7 degrees, and the pinion angle needs to be paralell to the front transfercase yoke/ prop shaft angle.

Example, if the engine slopes down and back at 5 degrees then the pinion needs to be down and back 5-6 degrees as well so that both ends of the drive shaft turn at the same speed. Both ends turning at the same speed, reduces vibration, provided the U joints are operating within their limits of angle.

Billavista has a great tech article on drive shafts, pinion and transfercase angles. He also talks about an alternative way to set the pinion with a traditional U joint, by setting the pinion up at the same angle that the engine slopes back BUT often times it will vibrate.

http://www.pirate4x4.com/tech/billav...aft/index.html

It doesn't explicitly talk about front pinion angles, but the information about rear pinion angles applies the same to the front.


Wally

[1946CJ2]

I lowered the front of the engine a little tonight and as it sits both yokes on the transfer case are at 0*. I think I need to call Jess or Tom tomorrow before I weld everything up and make sure my angles are ok. I plan on using 1310 joints.

the front is 0* at transfer case and diff, but the drive shaft would be at 25*. The length of this shaft is 30 5/8". I think I could use the "Super-Flex" universal joint with a standard shaft.

The rear is 0* at the transfer case, the diff is at 20* and shaft is at 22*. The length of the rear shaft is 34 7/8". I think I need the 1310 cv joint.

The suspension on the jeep is brand new 2.5 inch bds soa (front and rear), and their is hardly any weight on the build currently. I think the angle of the shafts will be a little less as the springs start to sag and weight is added to the build.

Thanks for any advice

[1946CJ2]

Well I spoke to a few different shops. They said it is all doable, however, one of the shops advised me that on my front pinion, I should point it 2* higher than the transfer case yoke (as for a cv). This is with running a standard front drive line. He said, that yes this will shorten the life of the u-joint, but if it shortened the life by 90% you would still have 10,000 miles on it And how long will that take on a front drive shaft. I will probably get some vibration but then again its a front drive line.

Next question, When I raise the pinion to 20* or so, should I put in a new fill plug (to raise the oil level)?

[elarsen]

Originally Posted by 1946CJ2

Well I spoke to a few different shops. They said it is all doable, however, one of the shops advised me that on my front pinion, I should point it 2* higher than the transfer case yoke (as for a cv). This is with running a standard front drive line. He said, that yes this will shorten the life of the u-joint, but if it shortened the life by 90% you would still have 10,000 miles on it And how long will that take on a front drive shaft. I will probably get some vibration but then again its a front drive line.

Next question, When I raise the pinion to 20* or so, should I put in a new fill plug (to raise the oil level)?

Make sure you have clearance for tipping the front pinion. 20 degrees seems like alot. As far as the fill plug goes you could move it up or just jack the front end up when you fill it. When I did my 60 rear I cut an oval , flipped it and re welded it up.

[1946CJ2]

If I am not going to run the yokes parallel, does it really matter where I locate my front pinion?

[elarsen]

What has worked well for me is rotating the pinion so it points at the tcase yoke (keeps it out of the rocks) and 5 or 6 degrees caster with a .5 extra caster on the passenger side if it will be driven on the road.

I have had to limp home on the front axle & the vibration is not bad, but it was there. You could greatly reduce that with a cv, but with the 420 I doubt you would be able to get a cv in there due to the reverse gear bulge.

[1946CJ2]

The bulge is why I am not going with the cv. Is the .5 extra caster for the crown in the road?

[elarsen]

Originally Posted by 1946CJ2

The bulge is why I am not going with the cv. Is the .5 extra caster for the crown in the road?

yup