As my other shows, I did a new mod. Now as most of you guys know, you change one thing and you end up changing a bunch of things. The simplest things turn into major pains. Anyway, I am trying to correct my driveshaft angle. It is not bad but it is not in phaze with the pinion. So I plan on having some one inch lift blocks machined to a wedge but I need to find the degree to get it right the 1st time.

So here goes:
X-case ouput to driveshaft is 85 degrees the driveshaft is 52.5" u-joint to u-joint, then 80 degrees from shaft to pinion. From u-joint to axle center is 14.5"

If anyone can decipher that or tell me how to calculte I would be greatfull.
Lator.....

Wow thats a confusing way to put it, what you are trying to do is get the yoke on the out-put and pinion to be at the same angle. So from what I can tell by your numbers the pinion needs to come up 5 degrees to match your t-case.

Flip it up like this again so we can see it.



If a 45 passenger bus leaves Chicago with 16 passengers, travelling at 56 mph, crosses a toll bridge, how much is the toll for the return trip?

All that matters to phasing is the angle of the t-case output and the angle of the pinion shaft.

The angle of the t-case/pinion shafts compared to the driveshaft angle only concerns the u-joint limits of flexibility.

But by changing the pinion angle won't the output angle change? If I flip it up again, then the weight won't be on it to get the correct measurements.
Lator....

Yes, changing the pinion angle will change the output angle. However it doesn't have to be perfect, just within a couple degree's. Overshoot the mark by 1 degree (or undershoot depending on which way you're going).

I just went through this, Mike.

You're making this too hard.

Go to harbor freight and get an angle finder. I paid $3 for this one:



With the driveshaft in, get the angle of the pinion and the angle of the Tcase output (you can use the flat surface at the outer end of the slip yoke for this.

The idea is to get these as close as possible. I had a Tcase output at 4 degrees and the pinion at 11 degrees, so I had 7 degrees to make up. I went down to my friendly offroad parts store and bought some 6 degree shims (biggest shims they had) and put them in. I'm now very close, considering the 1/2 degree margin of error on the angle finder.

My vibration is definitely less, though there is some noticeable vibe from 35-40mph that I'm not sure the cause of. I do know I need a longer driveshaft, so I might be getting some wobble at the slip yoke due to there not being a lot of slip yoke on the output shaft, and on hard braking, when the rear springs unload, the driveshaft is hitting the rear most crossmember, so that needs some significant notching as well.

The shim kit I bought came with new centering pins and cost me $39.

Already have the angle finder, that was how I had exact degrees. I know that ouput and pinion joints should be at equal but opposite angles for the least vibrations. I just did not know if there was special math for calculating which shim to use. I've only found 3 and 6 degree shims so I will probably end up with a 6 degree and a add-a-leaf to get the back end up just a tad. Whats funny, is before I had the pinion aimed towards the output and never noticed a vibration. Anyway, sorry I made it complicated, I was just trying to make sure you all had the info you needed. If I had not, you guys might have gone pirate on me and flamed me for it. Thanks for the help.
Lator....

I don't trust degree shims. Out back it's easy to cut and re-weld new spring purchases on. Up front I might be forced to run degree shims.

Why not? With new pins you bolt them to the leaf pack as if they were another leaf.

quote:

Originally posted by LordBiotree:
I don't trust degree shims. Out back it's easy to cut and re-weld new spring purchases on. Up front I might be forced to run degree shims.

You dont trust them and advise him not to run them but you might run them in the front? haha, chuck that bitch up on a mill and do that. Its about the same as cutting off and installing new perches.

I'm not running any degree shims. Out back I set the pinion angle with the purchases. up front the c's will need to be cut and re welded.

After 6 months of the truck being in the shop I don't think I'm going to tear down the front end just to cut and turn the c's.

well, for those of us who don't have a welder, bolting in a set of shims out back is a lot easier too, and they're plenty safe. They're a solid piece of steel.

You can also get weld-on shims for a permanent solution without having to cut and reweld the perches.

quote:

Originally posted by LordBiotree:
I'm not running any degree shims. Out back I set the pinion angle with the purchases. up front the c's will need to be cut and re welded.

After 6 months of the truck being in the shop I don't think I'm going to tear down the front end just to cut and turn the c's.

Cutting and turning the C's won't point your pinion at your transfer case. The only way to fix that is with shims. I welded on a set of 8 degree steel shims and I have 6 degree steel shims bolted in on the rear axle.

I personally don't like Aluminum shims. With the weight of my truck they flatten out.