Pinion Angle
 

Hey guys, does 5 degrees of pinion angle sound correct? I did some math and figuring and that is what i have come up with. I cannot check it because i have no motor or tranny in my truck at the moment. Just wanting to confirm this before i weld the axle perches in place.

Re: Pinion Angle
 

Three to five degrees down depending on what angle your transmission is at bolted in....

Re: Pinion Angle
 

always set all my hot rods between 3 and 5 degrees and never a problem. Can't remember where i got the info, but it was years ago. Craftsman makes a nice magnetic angle finder and it's fairly cheap. In fact just changed my old truck to a 350 auto this last week, had to build a crossmember, set it a 3 degrees.

www.picturetrail.com/skysoldier173rd

Re: Pinion Angle
 

3 to 5 degrees down??? Wouldn't the pinion be 3 to 5 degrees up?

Re: Pinion Angle
 

Yes 3 to 5 degrees down when compared to the drive shaft which should also be 3 to 5 degrees down from the transmission. I had often heard that the angle of the transmission yoke should be the same as the angle as the pinion yoke.

Re: Pinion Angle
 

You know what Zack, I need to appologize. I gave you some bogus info in your other thread regarding the pinion angle. I said that the pinion was 14 degrees up from the trailing arm mounts. Well, that was actually 4 degrees up from the trailing arm mounts. Only explanation is apparently I had my head somewhere it didn't belong at the time......:o

Re: Pinion Angle
 

I heard the same as GENIII above in his post, that the pinion angles offset with equal angle, only one up and one down about the same amount (3 to 5 degrees). I have seen shims used also to obtain the proper angle on trans mounts if the crossmember comes out too low to bring it up.

Re: Pinion Angle
 

LOL, np Fab. I haven't set the angle yet so it's all good. I guess the best way to do this is, level the perches and set the angle from that point???

Re: Pinion Angle
 

see page 5 for rules on angles:

http://www2.dana.com/pdf/J3311-1-HVTSS.PDF

basically, as mentioned above, the angle of the transmission and the angle of the pinion should be as close to equal (but opposite) AND there should be some angle at the u-joints

Re: Pinion Angle
 

I guess the best way to do this is, level the perches and set the angle from that point???[/QUOTE]

Yes. I personally have shims and spacers all over my driveline and although it works great (no vibrations), to me it's kinda jalopy style and I wish that my perches had been welded in the right place from the start.

Re: Pinion Angle
 

Thanks guys. I will review this info and go from there.

Re: Pinion Angle
 

Just to clear up any possible misunderstanding, the pinion shaft should be PARALLEL to the transmission output shaft. You can call them opposite angles if you want to, but relative to true horizontal, the angle is the same (and the same direction) on both.

Ray

Re: Pinion Angle
 

That's what I did with the original rear end I checked. I leveled the trailing arm mounts and measured the angle on the pinion yoke which was 86.4* Allowing for a little error, I would figure 86*......or up 4* from level.

Re: Pinion Angle
 

Having the pinion and trans parallel made a pretty bad vibration that I had go away. Definitely a better way of putting it!

Re: Pinion Angle
 

Ray, thanks for clarifying, just because I know the meaning of what I said doesn't mean others do:o

Re: Pinion Angle
 

Thanks again Fab. I will level the trailing arm mounting area and set it as you say at 4* up from level. That should put me within spec as you have described.

Next question: The rear i am using is out of a 86 donor truck. I do not have the drive shaft from that truck. I only have my original driveshaft. My OE shaft u-joint cups are a good bit smaller than that of the 86. What is the solution to this?

Thanks,

Re: Pinion Angle
 

You need a "transition" U-joint, which has two different sizes of cups. Measure for the cup diameter and span on the rear end yoke. You already know what size the shaft takes.

Now take the dimension info to your friendly local parts store and hope for the best. When you get that "deer in the headlights" look, head for a driveshaft shop. The driveshaft shop will charge you more, but at least will know what you are talking about.

Ray

Re: Pinion Angle
 

Awesome! Thanks guys for all your help. I guess i have never seen a transition u-joint, LOL.

Re: Pinion Angle
 

conversion joint is another term for it. any of the ujoint manufacturers should have a conversion list
ron