rear pinion angle question

[fubar_k5]

putting the dana 70hd in my blazer right now im sitting at 17 degrees at the axle yoke my drive shaft is at 21 degrees and my transfer case is pointing 3 degrees down. Im running a 208 with slip yoke. any ideas what my pinion angle should be ive tried seaching all i could find was cv setups.

any help would be awsome plan on welding the perches on tommarrow so I can have this done before a buddy of mine comes back on leave.

Forgot its got 56" springs not reversed with 7 inch shackles. I know slip yoke aint the right way to go just looking for an idea of what im suppose to be looking for. thanks

 

[bot0611]

yoke 17 degrees upwards
shaft 23 degrees downwards
t-case 3 degrees

and running slip yoke eliminator.

match the diff yoke and the d-shaft angles, you can run a straight line between thoose if using slip yoke eliminator.

 

[4X4HIGH]

T-case output and axle Yoke need to be the same (Obviously the t-case will point down and the axle Yoke will point up) also Ideally you don't want more than a 3 degree working angle on the U-joints or they will self destruct pretty quick.

 

[fubar_k5]

I was looking on pirate and according to how it says to caculate operating angles if i did it right i have a 4 degree operating angle off the pinion and 17 degree off the transfer case right? so what ur saying is I need to bring the rear pinion down to where it matches the transfer case operating angle?

 

[Hogback Fabrication]

Your pinion is pointed 17 degrees up right? If so, the operating angle at the diff is 4 deg and it's 18 deg at the t-case.

With that much lift and/or that short of a driveshaft you aren't going to get the angles close enough anyway. IMO 17 degrees at the pinion is the way to go, you can shim it up a little if you eventually go to a CV driveshaft.

The problem is that if you get your operating angles to match each joint will be operating at 15 degrees or so and you'll have vibration anyway because those angles are so steep.

You don't want to point the pinion up too much or you can starve the pinion bearings of oil, I've heard varying numbers for max angle (10-15 deg) but I know people that run 15 with no issues.

 

[fubar_k5]

I do plan on going to a better setup later. Just time and money right now wont allow it to happen. thanks for the help I understand it a little bit better now.

 

[4X4HIGH]

I find it hard to believe that your t-case is only 3 degrees down (how did you check this)?

 

[fubar_k5]

it was between 3 and 4 I checked off the output of the transfer case.