Been discused. havent found an answer.need personalized help with pinion angle.

[bot0611]

Ok so i took the damn T-case lowering kit off, my tail shaft sits @ -10* Y and my pinion angle sits @ +16* Y so the the choices ive seen here are torch and re weld perches or shims.

Ok i think i got it right now, both tailshaft and pinion have to point and the same angle one up and one down, am i good here??

so should i just get 6* shims on back, or rotate 6 * the axle and re weld.
Did i get it ok.

Thanks in advance guys.

 

[bp71k5]

You've got it right. You also have to make sure that each joint is still with the max operating angle. I'm not sure of the exact spec, but I've heard 3 degrees max is recommended for freeway speeds? Can anyone confirm that?

I personally don't like the shims cause the aluminum ones seem to break and they also add a bit of lift which makes the pinion angle a bit worse. I cut and welded mine which let me fine tune the angle.

If you have large tires, you might use 4 degree shims instead to account for a little axle wrap under load. The pinion will rotate up a degree or two to match the transfer case.

 

[bot0611]

Im leanning towards the perches getting re welded but dont want to screw it up.

tires are 33's for now but looking forward for some 35 after this summer.

That 3* (ive heard it as well) is between lets say pinion or tailshaft and the d-shaft itsefl right

 

[bp71k5]

That 3* (ive heard it as well) is between lets say pinion or tailshaft and the d-shaft itsefl right

Actually it's the angle that each joint operates at. One between the pinion and driveshaft and then the other one joining the shaft and trandfer case output.

 

[Hogback Fabrication]

Remember that if you rotate the pinion up 6 degrees it will change the operating angle at the joint at the t-case end.

4 degrees sounds more like it to me.

However, matching the angles in no way guarantees no vibes. As Brian mentioned, 3 degrees is what Spicer considers the maximum angle on it's universal joints without vibration and any lifted K5 is going to be beyond that.


The only surefire way to not have vibes is a cv shaft.

Other than that, some have the best luck matching angles like this and some have the best luck pointing the pinion at the t-case even though it sounds like the "wrong" way to do it.

I've had mine on dozens of 80 mph trips to and from Moab and never had noticeable vibes and I never ran a cv driveshaft (was a 4" lift).

 

[4X4HIGH]

Matching the angles at each end regardless of the working angle WILL eliminate any vibes (the matching angles are what stops the vibes) if the working angle is greater than 3* then you go through U-joints quickly. It is damn near impossible to get matching angles AND under the 3* max working angle on a short wheel based vehicle so matching the angles are the best choice if a CV shaft isn't in the budget.

I studied a bit on this subject once and found what i'm saying to be true to a T.

 

[bot0611]

Well a CV is around $300 and it aint what i wanted at the moment.

The vibes are notisable at high speeds but they are not continuos, i will try and jack the end with no springs and turn the yoke and see where it leaves me, thanks guys much appreciated

 

[bot0611]

I saw on a post here that zero rates move the pinion angle, is this true??

 

[Hogback Fabrication]

Matching the angles at each end regardless of the working angle WILL eliminate any vibes (the matching angles are what stops the vibes) if the working angle is greater than 3* then you go through U-joints quickly. It is damn near impossible to get matching angles AND under the 3* max working angle on a short wheel based vehicle so matching the angles are the best choice if a CV shaft isn't in the budget.

I studied a bit on this subject once and found what i'm saying to be true to a T.

In theory, yeah, that's right.

The further you get from a 0 degree operating angle the more violent the vibration that the u-joint will exhibit.

U-joints inherently vibrate, each cap speeds up and slows down as it rotates and causes a vibration. The whole idea of "matching angles" is to have the upper u-joint "cancel out" the vibration from the lower one or vice versa.

When you get to higher operating angles, each cap is speeding up and slowing down a lot more causing a lot of vibration. If that setup were in a perfect setting with no suspension movement and all the angles perfect etc. it probably wouldn't vibrate. In the real world, as soon as those steep angles get a little bit off those big vibrations from the u-joints translate to big vibrations in the drivetrain.


And of course the higher u-joint wear is directly associated to the higher change in u-joint cap speeds.


Reading here