Driveshaft angles

[blubuckaroo]

Funny how one thread will lead to an entirely different topic. I always thought that drivelines were to be set up so the pinion shaft and the transmission output shafts were parallel to each other. That means that when you do an extreme lift you need to rotate the pinion down. the relationship of the transmission shaft, the driveline, and the pinion shaft should make a "Z". If you don't you'll wipe out u-joints pretty fast. That is one of the reasons that you need offset "C" bushings when you lift the front. I see a lot of lifted cars with the pinion pointed up.

 

[cgbexec]

I was under the impression that the rear driveshaft should be as parallel to the axel pinion as possible within 5 degrees anyway and most of the angle would be in the double carden(sp?) joint at the transfer case. I would think that setting a drive shaft up like a "Z", would lead to a harmonic vibration problem. The front drive shaft is normally not engaged at high speeds, so it is not as important to have that shaft to axel pinion within 5 degrees, but in a perfect world it would be. I have never heard of making the angles equal, as this would add more bind to the overall shaft. The other issue is the double carden(sp?) joint should be better to handle an angle at high speed than a single U-joint, so why would you run the same angle at both? They make degreed shims to point the pinion up to reduce drive shaft angle. Your way of thinking would increase both angles. I am not an expert, but just trying to think my way through this logically. (That has gotten me into trouble before).

In fact I am installing shims tonight on the rear axel pads to make the rear drive shaft and axel pinion more parallel. My pinion needs to come up about 6 degrees to bring it within 2 or 3 degrees of parallel with the drive shaft.

Chris B.

 

[TJK74]

http://www.4xshaft.com
Look here in the tech/info under geometry.

Single ujoint shaft should be at equal angle at the tranny and pinion.
Double cardian should be at the same angle as the pinion

 

[Apogee]

Most EB's use a double cardan joint at the T-case...this is effectively two u-joints so the angle is divided equally between them resulting in no angle required at the pinion.

For a two u-joint shaft, you want the pinion and T-case output parallel in the rear so the angles are equal and in phase. The other option is to do a "broken-back" configuration where the shafts are not parrallel, but actually equal and opposite from a fictitious centerline. Both methods effectively match the u-joint acceleration profiles from end to end. The only reason to over-correct the rear pinion and have it point slightly lower than parallel is to offset wrap (pinion rise) during acceleration when the highest torque loads are being transmitted.

Here's a good graphical representation of the angular speed of a u-joint and how it varies: http://en.wikipedia.org/wiki/Universal_joint

 

[NMWILLY]

well your both right.

Here's an easy to understand article on the subject that applies to the Bronco drive shaft.

http://www.4x4wire.com/toyota/tech/driveline/

Enjoy!

 

[76Broncofromhell]

Funny how one thread will lead to an entirely different topic. I always thought that drivelines were to be set up so the pinion shaft and the transmission output shafts were parallel to each other. That means that when you do an extreme lift you need to rotate the pinion down. the relationship of the transmission shaft, the driveline, and the pinion shaft should make a "Z". If you don't you'll wipe out u-joints pretty fast. That is one of the reasons that you need offset "C" bushings when you lift the front. I see a lot of lifted cars with the pinion pointed up.

No. Broncos use double cardan "CV" style joints. You should do a search on driveshaft angles to better understand this topic. Once you do that, you won't post stuff like this - which WILL NOT WORK WITH AN EARLY BRONCO DRIVETRAIN. The C-bushings in the front ends are to adjust caster - not pinion angle.

Oh yeah recommended angle at the pinion with a CV rear shaft is 1-5* in order to avoid flattening the needle bearings.

 

[blubuckaroo]

No. Broncos use double cardan "CV" style joints. You should do a search on driveshaft angles to better understand this topic. Once you do that, you won't post stuff like this - which WILL NOT WORK WITH AN EARLY BRONCO DRIVETRAIN. The C-bushings in the front ends are to adjust caster - not pinion angle.

Oh yeah recommended angle at the pinion with a CV rear shaft is 1-5* in order to avoid flattening the needle bearings.

I'm sorry,
I thought this site was for help and discussion. ?:?
My mistake!

 

[Baja71]

No. Broncos use double cardan "CV" style joints. You should do a search on driveshaft angles to better understand this topic. Once you do that, you won't post stuff like this - which WILL NOT WORK WITH AN EARLY BRONCO DRIVETRAIN. The C-bushings in the front ends are to adjust caster - not pinion angle.

While C bushings come in degrees to help adjust caster for lifted vehicles, by doing so you are rotating the axle housing and thereby effectively altering your front pinion angle. ;D

 

[TJK74]

I'm sorry,
I thought this site was for help and discussion. ?:?
My mistake!

No worries keep asking questions... its what keep this site going and fun even if it has been asked before. Almost any questioned asked by 76Broncofromhell will be answered with do a search its been discussed before.

 

[TJK74]

While C bushings come in degrees to help adjust caster for lifted vehicles, by doing so you are rotating the axle housing and thereby effectively altering your front pinion angle. ;D

This is true I had to use the c-bushings to rotate my pinion up to lose the driveline bind at the CV after installing extended arm. In doing so I lost a bit of caster nut its still within 2.5 degrees and handles well on road

 

[blubuckaroo]

No worries keep asking questions... its what keep this sign going and fun even if it has been asked before. Almost any questioned asked by 76Broncofromhell will be answered with do a search its been discussed before.

Well I noticed that 76Broncofromhell is in Chico. Thought we might have to get together over a couple of Sierra Nevadas to sort this out. I work up there from time to time and got a hankering for those things!

 

[76Broncofromhell]

I prefer Keystone Light.

 

[Devin]

I prefer Keystone Light.

That explains a lot. ;D