Driveline question: Front axle to TC angle (1 Viewer)

[copasspupil]

My front axle to TC looks too pitched in either direction. Are you still looking for 8* or less in the pinion angle or is it different for the front as oppose to the rear?

My rear looks fine however.

I'll take pics tonight when I get home from playing with the kids.

I've got ~ 29 1/2" for the rear and 22 7/8 for the front length.

My drivelines currently measure 31 and 14 1/2". They are going to the driveline shop for the changes. I plan on going with a CV jointed for the rear but if the angle is too much do I go with a CV for the front too?

 

[Mace]

What type of Front Driveshaft? If it is a CV, then point the pinion directly at the tcase. If it is a Standard DS, then make the orientation of the pinion the same as the orientation of the tcase flange.

 

[Bug Gut]

I agree with the cv mounting, but the mounting of the std shaft the angles are to equal and oposite angles. IE if the output flange is 5 degs down the pinion should be 5 degs up.

 

[Bug Gut]

but actually you really dont need to worry about the front as much as the rear, due to the fact that you dont run the front shaft at freeway speed.

 

[copasspupil]

They are both tipped up

 

[Mace]

Copasspupil,

You are asking specific questions with very little information.

Here is a good primer
Tom Wood's Custom Drive Shafts - Driveline 101

 

[copasspupil]

Ok the rear are at 82/tc and 84 at the rear axle. The front axle is 75 and the front of the tv is 84 degrees

 

[1911]

The problem with the front is, that you must set (shim) the front axle to get enough caster so it will steer safe, regardless of the resultant pinion angle - unless you want to do a cut & turn like most SOA conversions. Un-equal pinion and output shaft angles will result in odd vibrations at speed and accelerated wear of the u-joints, but as has been said these are usually not overwhelming considerations on a 40 where the front drive shaft does not turn all the time and even then usually not at speed.

On the rear, what you really want is equal angles (or close to it) for both the pinion & drive shaft and the TC output shaft & drive shaft.

here is my truck for an example, before I shimmed the rear axle:

There is a 10 degree angle between the TC output and the drive shaft, and only a 5 degree angle between the drive shaft and the rear pinion. This resulted in a noticeable vibration right around 35 mph. Rotating the rear pinion down with 4-degree shims brought the two angles much closer and fixed the vibration. 6-degree shims would make even better angles, but 4's are what I had on hand and they fixed the vibration.

 

[Mace]

Ok the rear are at 82/tc and 84 at the rear axle. The front axle is 75 and the front of the tv is 84 degrees

How are your front and rear TC numbers different?

 

[Mace]

BTW, on the front axle, unless you are planning on doing a cut-n-turn, Your best bet is to set your caster correctly and then work on Driveline issues.

Remember, you typically do not go over 45 in 4wd. Driveline orientation is not a huge deal.

 

[copasspupil]

I get it now. My rear driveline I received from the po is so wrong in so many ways. I am going to use the front for the rear and buy a new one for the front. Shimming the front will help also.

Good question on the tc. I may have typed incorrectly. I will go check again