Ideal driveline angles

Just trying to figure out what degree shim I will need. Basically, I'm wondering how close the angles should be and if they are off, which direction should the difference be (should be pinion point lower or higher than output shaft)?

Thanks!

Forgot to mention...where can I get some steel shims for a reasonable price (probably in the 2 to 3 degree range)?

If you have a slip yoke at the xfer case then then the pinion yoke sould be at the same angle as the output yolk. If you have a SYE your pinion sould be in line with your driveshaft pointing 1-2 deg. down.

treadLightly said:

Just trying to figure out what degree shim I will need. Basically, I'm wondering how close the angles should be and if they are off, which direction should the difference be (should be pinion point lower or higher than output shaft)?

Thanks!

Forgot to mention...where can I get some steel shims for a reasonable price (probably in the 2 to 3 degree range)?

Click to expand...

it also depends on what kind of shaft you have. If you have a double cardon, your angle at the axle ujoint should equal to/ not greater than 1 degree, w/the pinon pointing down. If you have a single ujoint at each end then the angles between the two should be equal, but opposite. (like, 4 degrees down at the t-case and 4 degrees up at the pinion)

Tom Woods sells shims.

So...if I have two u-joints than I can be within 1 degree in either direction but no greater than that? And it would be optimal if I had them at equal (but opposite angles)? Is that all correct?

treadLightly said:

So...if I have two u-joints than I can be within 1 degree in either direction but no greater than that? And it would be optimal if I had them at equal (but opposite angles)? Is that all correct?

Click to expand...

Your close,

If your shaft has 2 ujoints on it, then you must have those angles EQUAL. These angles will be, one pointing down(t-case end) and one pointing up (axle pinion end) The reason for this is that you are trying to balance and cancel out any vibration in the ujoints. They must be equal.

If you have a double cardon shaft (like on the front shaft) that has three ujoints in it. Two by the t-case on one at the pinion. The angle of the u-joint by the pinion should be no more than one degree, with the pinion being pointed down,(like, make it straight, then move the pinion down one degree) the reason for pointing the pinion down it that when you accelerate your springs will natural wrap slightly thus rotation the pinion up that one degree, then the pinon u-joint angle will be zero. The two joints at the upper end of a double cardon shaft are designed to absorb the remaining angle.

I would go to Sears and get a magnetic angle finder, 10 bucks.
To measure angles you place the angle finder on the driveshaft (idealy it should be on the splines of the slip yoke but usually that part is to small, so find a clean undamaged part of the tube to place your angle finder on, record this angle. Now you must measure the pinion (yoke) angle. (the pinion yoke is the thingy that holds the u-joint in the axle) To measure this angle, look for the flat spot at the end of the axle tubes, right buy the differential covers, on mine they are round with a hole in the center, about as big as a 1/2 dollar. These surfaces are parallel to the pinion face. Slap on the angle finder and record this measurement. (You can also place the angle finder on the face of the pinon yoke if the d-shaft is removed.)

When I put on bigger springs on my 2000 I had a difference of 7 degrees, so I added a 6 degree shim, thus leaving me with my 1 degree down angle. This worked well for my double cardon shaft and sye.

I would also do a search, I remember seeing a picture that illustrated this very well.

Get a angle finder and may the force be with you.

Tom

I am still confused on where to place a magnetic angle finder on the rear diff. I have searched and readread about the "spreader holes" which I believe are the 2 holes just outboard of the diff cover in this photo of my 8.25" Chrysler diff.



I have also read about a flat spot one the outboard alxe tubes, which I have yet to find.

There are four raised "studs" over the pinion shaft if the photo below would be an acceptable location to take a reading at?



Thanks and sorry for a noob question.

00xj said:

......................I would also do a search, I remember seeing a picture that illustrated this very well.

Get a angle finder and may the force be with you.

Tom

Click to expand...

This post is several years old so, I must have done some searching to find it. I had to order the magnetic angle finder to do the job well. It has been here and I searched a ton more since it arrived. All I am asking for is a sentence or two on taking measurements from the rear diff. I haven't even been a forum member for very long and I have seen the same newbie questions answered many times over and yet I can't get help on this one. All I need is to know where to take an angle measurement on a 8.25" rear diff.

If, someone could help, I would appreciate it. I became a paying member to hopefully get some guidance from your extremely knowledgeable members and maybe I judged incorrectly. Thanks for your time,

Reed

I have noticed over the years that every one knows eactly the angle the front and rear diff should be and where to buy an angle finder to measure it. No one knows where to place the angle finder. I gave up on the advice and eye-ball mine then drive it and check for vibes.

You freaking take the diff cover off, and put a straight-edge metal ruler across the face. Then stick your angle finder to the ruler to see what angle your pumpkin is sitting at. Common sense dude, c'mon.

I took my angle off the nubs above the pinion.

take the caps off the yoke and set it on the yoke face.

Keep in mind, you can use any surface that is known to be 90 degrees to the pinion shaft.

Heck, you could even use the END of the pinion shaft for that matter.

And you don't need some fancy magnetic setup, -just go to home depot and get a cheapo angle finder, -they work just fine.

The accuracy of the angle finder isn't that important because you are using it for comparative purposes, -not building a 130 story building with it. Try to use the same edge of the angle finder when doing your comparisons between the angles.

I'll tell ya, being able to hunt down a drivetrain vibration and FIX it with a little patience and not a lot of money is a very gratifying experience.

It's not too tough, -hang in there and git 'er done.

barillms said:

You freaking take the diff cover off, and put a straight-edge metal ruler across the face. Then stick your angle finder to the ruler to see what angle your pumpkin is sitting at. Common sense dude, c'mon.

Click to expand...

You're right I should have done that when it was off. I know now that I should have. I am just learning about all of this. I pulled the whole diff off to take to it to someone to correct my blunder when I replaced my pinion yoke and screwed up the backlash adjustment. I didn't think to tell the guy to not reseal the cover when I dropped it off. I already refilled it and was looking to save a few bucks to not remove the cover again, The yoke was replaced because of driveline vibes that started right after I purchased this "set up" XJ.

The vibes took out the pinion yoke, u-joint and the rear half of a NP242






I am just trying to reduce the vibes now. The TC drop came in late after the carnage and since it is not a needed DD I have test driven it only and have lesser vibes after the TC drop.

Intial readings on a slope (fore to aft) indicate a 1/2° difference from valve cover and rear differential spreading holes. I want to check this on various surfaces to make sure. In any event, this is a "beginners" rig and I am not investing the time, work and money in a HnT for an $1800 rig.

Since I already have a new oil pan (previous owner bashed it and rockauto.com is cheap) , gaskets and rear main seal, I'll install them and I will probably dump this and move up. I appreciate the suggestions and guidance.

Thanks

Reed

F9K9 said:

This post is several years old so, I must have done some searching to find it. I had to order the magnetic angle finder to do the job well. It has been here and I searched a ton more since it arrived. All I am asking for is a sentence or two on taking measurements from the rear diff. I haven't even been a forum member for very long and I have seen the same newbie questions answered many times over and yet I can't get help on this one. All I need is to know where to take an angle measurement on a 8.25" rear diff.

If, someone could help, I would appreciate it. I became a paying member to hopefully get some guidance from your extremely knowledgeable members and maybe I judged incorrectly. Thanks for your time,

Reed

Click to expand...

This is from a hour ago and should answer your original question.

RCP Phx said:

This is from a hour ago and should answer your original question.

Click to expand...

That is what I took mine from. Thanks!

Great; I love it. A little sarcastic comment net all the correct answers. :yelclap: :yelclap:

Any hardware store will yeild you an angle finder. It does not need to be magnetic.

The FSM, shows how to measure angles, and that pix of the angle finder stuck on the back of the axle is not it.

You are measuring the difference between the pinion and the driveshaft also the output yoke and the drive shaft.

Use the U-Joint caps in the pinion side of the U-Joint as reference for the angle finder.
Use a short socket and put it on the cap, to extend it past the strap, then hold the angle finder on the socket. Read the driveshaft angle on the guage. Do the same exact proceedure on the output yoke of the TC.
The angles should be the same but opposite for the stock shaft.

Ron

Edit: OOps! Wrong thread!