Indexing pinion angle

[ww2steel]

Hello. I am just finishing up a spring over axle (SOA) conversion. Front is done. I am tweaking ride height by adjusting rear shackle height. Once done with that I can index the pinion. Rear shaft is a double cardan (both are, actually). Current angles are 29° at the Transfer Case (double cardan end), and 24° at the pinion. (Also, it's now a T-176 , the TF999 Transmission has been swapped back out.)

1) I read that the single joint end of a double cardan is supposed to be run at 0° since there is no opposing joint to cancel out vibration, correct?

2) To accomplish that I will have to tip the pinion up about 24° (after shackle adjustments, running about 1.7° down angle at rest to account for torque). Will running the pinion tipped up like this cause problems? The only things I can think of are possible difficulty bleeding the wheel cylinders (so do on a slope), and possible lubrication issues of the pinion bearings. Am I going to lunch the bearings if I tip it up that far? (Tipping the pinion up will also help the Transfer Case angle.)

3) I also read that running a U-joint at 0° causes brinelling to the needle bearings and races since they don't move/ lubricate. Understanding that I probably will be a degree or two off anyway just because of everything involved- is this something I should worry about? Should I plan to run it at 1-2°?

Thanks,
Mike

 

[tarry99]

Without getting to technical here..........I would take this conversation up with whomever is building the drive-line.......Guys like Tom Woods or High Angle would be my choice.

 

[Kane]

I have a tom woods double cardin Shaft. He told me to set the pinion side of the Shaft at 3-7 degrees because when you accelerate the springs will flex and that will keep the shaft at no less than 0 degrees.

 

[Posi]

I set mine at 2*, I have a traction bar as well.
If your concerned about the pinion bearing do to the angle drill the diff and add a zerk fitting.

 

[ww2steel]

Well, I guess I'm building/ correcting the driveline. I can ask the guys at the shop that does my driveshafts- this rear one is the last of four recently. The problem is that some master mechanic previously put in this double cardan shaft when they put in that horrible 4" lift that made this all necessary. They had about a 20° angle on the lone joint, which I guess explains the wobble I got at a specific low speed. (I assumed it was a tire harmonic.)

Keep in mind I am correcting problems created in just about every system on this Jeep. During the time I didn't own it the guy got ripped off every time he went by a shop.

So maybe 5° down to keep a minor angle on it?

I am concerned about axle wrap with the very soft springs and SOA, so the traction bar may be in order. In that case maybe 2°. The zerk is for normal moly type grease so it will stay in there longer?

Thanks,
Mike

 

[Posi]

I would be concerned with axle wrap with a 360 and yj springs as well.
I'm running a 360 with 1/2ton wagon springs using a traction bar.
Yes on the molly
I'm at 19* and didn't feel the need to install a zerk fitting.

 

[ww2steel]

I put the 360 in about 21 years ago when I was 17. If I want to go fast this would be the last vehicle I would take. Never the less, I am positive you are correct. I put in the lighter YJ springs (non-towing, non- hard top). Without shocks or sway bar connected I can jiggle the thing with two fingers. They are obviously super flexy. If they are too soft, I guess I just swap stuff again, which kind of IS my hobby on this vehicle. Despite using it for a daily driver in high school, I am sure I have more hours working on it than driving it.... which is, of course, an obvious statement for most of us that like CJs.

Thanks again. I just wanted to see if anyone saw a fundamental flaw in my idea. I'll probably zerk in when I do some rear-end work in the future.

Mike

 

[Jimbos76cj]

Ive never heard that the drive shaft sould be at a 0 degree angle for a single joint system. A standard drive shaft should be set so the Transfer Case yoke and rear pinion are paralell. so id the Transfer Case is 10 down the pinion should be 10 up. thats how they cancel each other out. For a double cardan shaft the rear pinion should point right at the reat of the Transfer Case yoke then minus 2-3 degrees for spring deflection. It doesnt really matter what angle the Transfer Case yoke is with a CV shaft (with in reason).

 

[Hedgehog]

If you don't mind, I must ask a side question. How do you measure the main shaft angle?

I've been thinking that I'm running at 0*, but then again I have no idea what the main shaft coming from the Transfer Case angle is.

 

[Torxhead]

If you don't mind, I must ask a side question. How do you measure the main shaft angle?

I've been thinking that I'm running at 0*, but then again I have no idea what the main shaft coming from the Transfer Case angle is.

I put a level/protractor on the pinion yoke end after removing the drive shaft.

 

[Hedgehog]

Small perch. Is it long enough to get a really good reading ...... Wait, you wouldn't have suggested it if it weren't. I'm putting the rear axle back in this weekend so this is the perfect time to add a shim, if it needs it where do you get steel shims? I'm shooting for parallel main and pinion shafts.

 

[Posi]

https://www.wfoconcepts.com/cr/Axle-Shims/3225
If you shop around I'm sure you can find steel shims for less.

 

[Lumpy Grits]

Find a shop that works on semi-trucks.
They use steel shims from steering and front end alignment.
LG