I have a PR44 Unlimited and wondering how to dial it in. I know that with a stock D30 you try to run caster at 6-7 degrees (when lifted 3"-which is me). So, does that mean I set caster to 0 or 1 degree because of the 6 degrees built in from Dynatrac? I had this axle installed locally and they aligned it. It drives straight, and it's centered fine but I'm getting a vibration through the shifter. I'm not sure if they have the caster correct. I'm using a Coast driveshaft and I know vibrations can explode the transfer case if bad enough. The vibration is bad enough that I don't like resting my hand on the shifter going 50mph plus. Also, what would be the perfect pinion angle? Thanks for any input.

 

If you got the PR-44 with the castor corrected, you'll want your pinion pointed directly towards the t-case. Thats the purpose of the castor corrected version. Take a pic of yours and post it up. One of two things could be happening, pinion angle needs tweaking, or ds not balanced.

 

bubba, he has a prorock 44 unlimited and it comes with +6° of caster built into it. T&E, i would definitely try reducing the amount of caster you have so that the pinion is closer to being in line with your drive shaft. you'll most likely not be able to get it dead on and that's okay. technically, if you were to take a measurement of your caster now, it should read greater than +6° if it's off. when it's on, it should read 6° or there abouts.

 

How are you measuring your angles? Unless you have proper alignment tools, the angle should be measured (with an angle finder) from your pinion flange- nowhere else. There is no other place that you can guarantee you'll get an accurate measurement.

Your first statement is incorrect. Factory caster is set at 4*. This provides 2* of up tilt for your driveshaft. This is 6* of separation. If you did as you stated and adjusted your caster to 6 or 7*, your pinion would be parallel with the ground or tilted down 1*. Obviously, this is incorrect. The ProRock 44 Unlimited has an additional 4* of caster built in (10* of separation). If a rig had a stock housing and caster was at 1* (a common measurement with a lift and the pinion angle corrected), when a PR44 Unlimited was installed the new measurement would be 5*. This would be more caster than stock, and actually better than stock as 4* is really very minimal as a caster angle.

Since we know the angles of a stock housing and PR44 Unlimited, we can measure the pinion angle and know the caster angle. Again, by measuring the angle of the pinion flange (BTW-assuming level ground). The caster is measured back from 90* and the pinion is measured forward (or up) from 90*. The stock housing has 6* of separation. If the pinion tilt is 4* up we know that the caster is 2* back (or down) for 6 of separation. The PR44 Unlimited has 10* of separation. If the pinion tilt is 4* up we know that the caster is 6* back (or down) for 10* of separation.

Clear as mud now?

As WOL mentioned, the PR44 Unlimited housing has plenty of caster built in for your application. If you tilt the pinion to make it in line with your DS, you'll still have enough caster to steer very well.

 

Thanks all. Got under there today and the pinion is defanetely not pointed at the transfer case (or inline with the driveshaft). It's pointing slightly down. I think I'll buy adj uppers to correct this. I know I can shorten the adj lowers that I already have but I like the ability to have full adjustment. Thanks again.