Dana 30 pinion angle Question

[bae146]

I have a 95 jeep yj with the stock dana 30 front end.  I have a C/V front driveshaft.  The angle off the face of the output yoke on the dana 30 is 4.5 degrees up.  When the C/V shaft is hooked up the angle of the D/S is 11 degrees up.  So you get my dilemma......  Should I replace the C/V shaft with a regular shaft?  I can't get my angle finder in to see what the angle coming out of the transfer case is.  If I shim the axle I loose all my caster.  I have removed the vacuum disconnect and installed a tj shaft so this is spinning all the time.  So I need a full time solution.   Any ideas??

[bae146]

I know bnine has some experience with this set up.  Does anyone know who he did the work for?

[BlackYJ]

How much lift are you running?  Shackle lift?

Since YJs have a HP front, you can getting away with more lift before you have to go to a CV shaft.  Typically you are good with about 10-12 degrees on a standard 2 joint shaft.  Since you have 4.5 on the yoke and 11 on the DS, you should be able to get away with a std shaft.

[Bnine]

Ultimately, even with a CV, if you can get the angles to cancle out, it is ideal.

ie, 15 degree shaft, 5 down on pinion, and 10 for the 2 joints in the in the CV.

5 degrees is the max operating angle you want on any single ujoint.

But, with a YJ front, you really needn't worry about the pinion so much. The front shaft will only turn in 4wd, which is typically at low speed, and doesnt really matter.

The reason CV's were added to TJ and non disco XJ's is because the front shaft always turns, and they couldnt get a typical 2 joint shaft to align properly and eliminate vibrations.

If you really want to balance it out perfectly you can cut and rotate the perches, or add a small shim.

2 degree shim will bring the shaft close to 9 degrees total, pinion to 3.5, and the CV joints to almost 3 each. That all pretty equal.

That would drop your caster to about 5 degrees. If you are running 35's, 5 degrees caster is about optimal.

If you are running 33's I would leave it where it is and run it.

Are you getting vibrations somewhere?

Are they only when 4wd is engage?

Or are just finishing some installing, and double checking your specs?

hth

[BlackYJ]

2 degree shim will bring the shaft close to 9 degrees total, pinion to 3.5, and the CV joints to almost 3 each. That all pretty equal.

Wouldn't a 2 deg shim put his pinion at 6.5, not 3.5?

Also as stated he is running a TJ pass shaft, so the DS is always turning.

[Bnine]

2 degree shim will bring the shaft close to 9 degrees total, pinion to 3.5, and the CV joints to almost 3 each. That all pretty equal.

Wouldn't a 2 deg shim put his pinion at 6.5, not 3.5?

Also as stated he is running a TJ pass shaft, so the DS is always turning.

Only if he shimmed it down, what Im sayin is shim the pinion up.

I thought he was asking about the TJ swap, my bad.

It should still run ok as it sits, I would try first. If not, cut and rotate, or a couple degree shim.

[bae146]

How much lift are you running?  Shackle lift?

Since YJs have a HP front, you can getting away with more lift before you have to go to a CV shaft.  Typically you are good with about 10-12 degrees on a standard 2 joint shaft.  Since you have 4.5 on the yoke and 11 on the DS, you should be able to get away with a std shaft.

I have 3.5 inch BDS lift, no shims in the front, with a 1 inch longer shackle.  I have 33" tires.  I managed to squeeze my angle finder onto the output yoke of the transfer case.  It is pointing 6Degrees up as well.  I have no transfer case drop installed.  I am already running a cv driveshaft.  I thought that the cv shaft should point directly to the transfer case?  This would nessitate that I change the angle of the pinion from 4 degrees up to 10.  Of course that would bring my caster to 0  which would be a bad thing.  Being as this DS turns all the time I want to get rid of the vibe that I do have.  That and I like to do things right as they alway last longer.  I will try a 2.5 degree shim and see what happens.

[BlackYJ]

Is the shaft properly balanced?

Are you at about the same amount of lift I have so I am curious if it is not something else.

[bae146]

New shaft from DSI about 4 months ago......

[Bnine]

You definately dont "need" to point the pinion directly at the t-case when running a CV. It is just a common method that works.

You can run as much angle as you want on the pinion joint, up to 5 degrees provided the joint angles are cancelling eachother out as I explained previously.

hth

[bae146]

Well I took both drive shafts into DSI this morning.  The centering ball needed replacement so I asked them to replace the u joints while they were in there.  I am having the rear lengthened as it is a bit short.  Hopefully I will have them back tomorrow pm for the weekend.  This one car thing is no fun.   Although the wifes car is nice with AC and all that fancy stuff.