Thread: driveshaft angle from trans to rear

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ok im building a 32 as some of you guys already know , my question is i got a winters quickchange and a muncie trans , the driveshaft seems to have to go on a big angle to connect to the rear since the yokeis located low on quickies , what is a good way to set pinion angle when the drive shaft has to dive down pretty far ......

3 degrees down works for me...

what about the driveshaft pointing down a bunch of degrees is that normal ?

Well, with the low pinion on a quickie, has to be that way. Look at the driveshaft angle on some of the 4WD stuff......

Dave, most of the severe driveline angles on 4x4's have a CV (constant velocity) type driveshaft.

Godspeed32, Is their anyway to rotate the rearend housing (pinion snout) up? Thereby decreasing driveline angle? If not, you can look into a CV type drivleshaft.

I am not really sur ewho could give you all of the information that you would need, or where you can get one.

I set the car on the ground - or at least mock it up at ride height, with the pinion yoke set at 0*. Then I measure the down angle at the transmission yoke, and bring the nose of the pinion yoke up until I have the same angle.

If you really want to dial it in, measure the angle between the output shaft of the trans and the driveshaft, then between the driveshaft and the input shaft of the pinion. Both angles should be equal, and between one and three degrees.

It's important to have the angles equal because U-joints are not constant velocity. They actually slow down and speed up as they rotate. Making the angles equal causes them to change velocity at the same time and it eliminates vibration. If the angles are unequal, you're looking for trouble, vibration and wear.

Take a look at this: http://www.iedls.com/ptsetup.html

Generally, you want the pinion pointing up about 3 degrees, and the tailshaft pointing down 3 degrees. They don't need to be aimed at each other, and in fact it is preferable if they don't. You want the u joints to "work" as they rotate.


Don

Originally Posted by Dave Severson

3 degrees down works for me...

me to it works good on chevys to dave

Like Don sez, the joints must '"work" as they rotate. A driveshaft that runs straight will eat u-joints in no time. the rollers wear into the cross in one spot, and there's no movement to spread the grease around.

All good advice -
Another item to consider is to make sure your driveshaft builder times it correctly - I recommend someone like Denny's in Syracuse, NY to manufacture it to take your engine power.
They had an internet special on the HD's when I bought mine and it was enough to pay my NY sales tax and shipping and then some. Their aluminum pieces are pretty but I'm not convinced they are worth the extra $100+.

Originally Posted by Dave Severson

3 degrees down works for me...

Dave,

You point both the tail of the trans and the nose of the pinion down?

Here is Tom Woods' Driveshaft 101 link.
http://www.4xshaft.com/index.html
go to "tech info" and choose "Geometry 101"
The info applies regardless of the type of car/truck.

Tom also builds really nice driveshafts.

mike in tucson

Originally Posted by Henry Rifle

Dave,

You point both the tail of the trans and the nose of the pinion down?

The trans should point down 3 Deg and the pinion should point up 3 Deg, cancelling each other out for smooth stop-start mechanical transitions. Pointing them both down is an invitation to U-joint failures thru bind.

With the car level and the crank down 3*, I try for 2* up on the pinion. That way when you're cruising, I figure the engine torque will pull the pinion up another degree or so and you'll be flush. If you lay 'em both in a 3* down/up, then you're gonna be way out when the car is under power. At least that's the way my feable mind sees it.

Compensating for under load conditions sounds like a good idea to me. I would want to dial it in dead nut at common cruising speed and hopefully still be within tolerance coasting and under full load.

There's a few painfull ways to do this. Inductive proximeters or optics come to mind quickly. Cheaper would be to strap on a dial level and have the neighbor or brother in law open the door and stick his head under the rod while we're going!

You guys do that and I'll just use my $1 dial level and scab mine in and run her 'till she shakes or breaks!

Kitz