Axle Shims, Newbie's searches inadequate

[Ray H]

I know that some people have good luck pointing the pinion at the tcase output without a CV shaft. I cant explain that. Here is the geometry of it and how it should "theoretically" work. Just to add, the reason that the pinion tends to point upward when you install lift or arched springs in an XJ is because the center pin on XJ springs is offset to the front of the leaf pack, which is sloped upward on an arched spring, so the pinion will tend to point up unless its shimmed back to level. this site doesnt take spring wrap into consideration so you still should allow a degree or two for that. http://www.4x4wire.com/toyota/tech/driveline/

 

[F9K9]

RAY H that's what I originally planned to do was going with http://www.4x4wire.com/toyota/tech/driveline/ recommendations when I ordered the 5° shims but, I believe I'll try GoJeep's recommendation of allowing for the 3° axle wrap. I went crawling today and my XJ's "to do" list grew a little during the ride so, I'll have plenty to do while waiting on the shims.:laugh:

 

[Gojeep]

If he's not running a CV shaft, he needs to lower the pinion a couple degrees.

No this is not right. I have fitted many of these to XJ's and that has not worked at all. When you fit a transfercase drop, as he has done, the angle in the uni at the transfercase end lessens by 2 degrees. So without a double cardon joint, you must equal any change at one end but doing the same to the other. To lesson the angle by 2 degrees at the pinion end you must raise it by that much. To do that you must have the thin side forward. I have proven this time and time again using a angle finder and all and have cured the vibes by doing so. Ran that way for 11 years no problem at all.
Doing it your way would give a 7 degree difference between uni angles. Doing it my way gets it back to 3 degrees the same as stock.

 

[F9K9]

:confused1The TC 1 " drop lowered the output angle by 2° therefore I originally had a difference of 7°. If, I raise the pinion angle 2° I will then be right back at 7°. I could be just not seeing this relationship correctly but, I know GoJeep definitely knows his stuff on these rigs but, I am confused even more.

:confused1

 

[boise49ers]

:confused1The TC 1 " drop lowered the output angle by 2° therefore I originally had a difference of 7°. If, I raise the pinion angle 2° I will then be right back at 7°. I could be just not seeing this relationship correctly but, I know GoJeep definitely knows his stuff on these rigs but, I am confused even more.

:confused1

I don't blame you. Do what I said. This link should make it perfectly clear. You get to this by putting the thick part of the shim forward. This is how I run mine with 6" of lift with no SYE and no vibes at all with a Dana 44. I had it running at 75mph yesterday after competition at our Rock Course So take that for what it is worth.

http://www.4xshaft.com/index.html

 

[boise49ers]

I ran a TC drop for while and it made no difference. So I got rid of it to get back the clearance. If it is an inch or less I'd take it off and try to align your TC shaft and pinion shafts like Tom Woods recommends. My son runs about the same set up I have , but with a 8.25 like yours. He has some vibration. The 8.25 are very sensetive to driveline change as you have inherantly found out. Good Luck !

I don't blame you. Do what I said. This link should make it perfectly clear. You get to this by putting the thick part of the shim forward. This is how I run mine with 6" of lift with no SYE and no vibes at all with a Dana 44. I had it running at 75mph yesterday after competition at our Rock Course So take that for what it is worth.

http://www.4xshaft.com/index.html

 

[F9K9]

Thanks, boise49ers! I am going to try the 2° shims with the drop as comprimise for now and see what happens. If. that doesn't cure it then, I'll yank the drop and shoot for shims that will get it as close as possible to the angle then.

I have a sneaking suspicion that my angles are going to change anyway before then.

 

[Ray H]

No this is not right. I have fitted many of these to XJ's and that has not worked at all. When you fit a transfercase drop, as he has done, the angle in the uni at the transfercase end lessens by 2 degrees. So without a double cardon joint, you must equal any change at one end but doing the same to the other. To lesson the angle by 2 degrees at the pinion end you must raise it by that much. To do that you must have the thin side forward. I have proven this time and time again using a angle finder and all and have cured the vibes by doing so. Ran that way for 11 years no problem at all.
Doing it your way would give a 7 degree difference between uni angles. Doing it my way gets it back to 3 degrees the same as stock.

Like I said, I can't explain why different angles at the tcase and at the pinion works for some people, can you? All I can do is give him the facts of the geometry. According to the measurements he gave, the geometry and the physics, he needs to lower his pinion. Thats all I can say about that. I dont make the rules.

 

[Gojeep]

OK, see if I can explain it this way. The picture shown is not how it looks after the transfercase has been lowered. It is no longer parallel with the ground or the pinion for that matter. The pinion without any shim is still parallel with the ground but the transfercase is now pointing down towards the ground by 2*. So to make the pinion angle parallel with that again, you have to point it up.
In your mind, draw a line though a dropped transfercase after it is pointing down. Now do the same with a flat pinion. It is not parallel with the line now that you have drawn through the transfercase is it. So how do you make it parallel again. Pointing it up. I am not going against the rules laid out what so ever. Just dont confuse yourself by making the relationship with the ground and not the components your are trying to get that relationship with.
How about this. Just rotate the whole picture so the transfercase is pointing down. See how the pinion now points up yet the relationship between them is un-changed?
The only thing different on a XJ is that, like from the factory, there has to be a 3* difference to allow for pinion rise during acceleration due to having a spring over which causes more rise than a spring under or a link arrangement.

 

[Ray H]

Im with you on that. But here are his reported degree measurements with the tcase drop installed and no reference made to the ground.
"Reading my TC output angle was exactly 0° when measured using the transmission pan for a mounting location. I used the differential spreader holes for the differential measurement and the angle was 5° upwards toward the TC output."
If his measurements are right, any way you slice it, theres a 5 degree difference between his pinion and output and the pinion is tilted up towards the output.
I make no claim that his measurements are correct, only that if they are correct, his pinion is too low.

 

[F9K9]

I do not know what the transfer case's and pinion angles were before the 3.5" RE Superflex lift was installed on my rig. It was already installed when I purchased it. The spring pack that comes with the kit obviously raised the pinion 7° ABOVE the TC's output. The drop lowered the TC output 2° bringing the pinion's angle to the current 5° above the TC's output difference.

For my application to look like the diagram would take a 5° shim (which is what I originally ordered) to LOWER the pinion to make them parrallel. To give it the 3° angle below parrallel that GoJeep recommends I would need to rotate the pinion DOWN 8°. I believe GoJeep is thinking that that my pinion is shooting 5° BELOW parrallel. In either case the 2° shim that is ordered is isn't going to do anything that I need to correct the situation.

Do I have a grasp of it now?

 

[F9K9]

I thought about this at work today and know that I have some errors in my thinking in the early part of my last reply but, generally I believe I have a handle on it.:dunno:

 

[boise49ers]

I thought about this at work today and know that I have some errors in my thinking in the early part of my last reply but, generally I believe I have a handle on it.:dunno:

I have went thru the same thing as you and finally settled for what I have posted. I see where GoJeep is coming from with his thoughts, but I'm with you and think if you have drop in the TC it isn't that much. If you have a driveline specialist in your area they can explain it in easier terms and show you on the rig what you will need to do. Our local guys don't charge for that service.
You probably have a good grasp on what you need to do. Try it then run it, and if it still vibrates alot swing by the driveline shop.

Hey I had to show my pics from this weekend on the RTI. I know everyone says articulation is over rated, but I was in the 800s and took second place on our rock course. XJs did real good Saturday. I'll have video link soon too.
This is from a Daily Driver also !

 

[F9K9]

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,If you have a driveline specialist in your area they can explain it in easier terms and show you on the rig what you will need to do. Our local guys don't charge for that service. You probably have a good grasp on what you need to do. Try it then run it, and if it still vibrates alot swing by the driveline shop.

Thanks for the advice. There is not anything available to me locally but, there is an excellent shop that is over an hr away. I have already been working with the owner for a Limited Slip install in this "DD".

BTW, you have an excellent wrencher just west of you that hosts the S-10 CrewCab forum http://www.s-10crewcab.com/phpBB2/profile.php?mode=viewprofile&u=2

Holler at him sometime.:wave1:

I guess I will cancell my order of the 2 degree shims for now and just keep researching.

I want to thank everyone for their input to this newbie. If, you ever get a chance to pass on thru my area then a couple cold ones are on me.

 

[F9K9]

...................Hey I had to show my pics from this weekend on the RTI. I know everyone says articulation is over rated, but I was in the 800s and took second place on our rock course. XJs did real good Saturday. I'll have video link soon too.
This is from a Daily Driver also !

I am quite impressed but, look at the source

Looks good to this newbie!

 

[Gojeep]

Sorry my mistake but I was just thinking from the point of view that from stock, dropping your cross member lessons the transfercase angle by 2 degrees so you need to do the same to the pinion. I didn't take much notice of the pan angle as you cannot use that as a reference point. There is no guarantee that it has any relationship directly with the output shaft angle. Look how the pan even is shallower at one end compared to the other. Dont know just how good that is compared to the output shaft and if it is angled to help drain the fluid. Using even the drain plug on the back of the transfercase is better than the pan as it is at least part of the transfercase and machined flat and parallel to the output shaft.
Take that angle there if you could so we know where we stand. I looks like the leaf springs you have must have rotated the pinion greater than even re-arched stock leaves with add-a-leafs for instance. I found the pinion unchanged with that setup.

 

[F9K9]

.............................................Using even the drain plug on the back of the transfercase is better than the pan as it is at least part of the transfercase and machined flat and parallel to the output shaft.
Take that angle there if you could so we know where we stand...............................................

That's a good point. I may have actually searched a little too hard. The transmission pan was one place I read about to place the magnetic angle finder on. I also read about using the valve cover as a reference point but, mine is aluminum and the later models are stamped steel? I'll try both if, I can nurse it to a level spot to measure. I've got two bent and cracked oem upper control arms from a ride on Saturday. I'll compare the tranny pan, TC drain plug and valve cover and post up the results.

 

[XJsurf]

I have a quick question. This weekend I upgraded my leafs from an RE 3.5 to the 4.5. Now I believe that I have 2.5 shims on the rear. Do they need to be increase due to the height change?? I also have a sye with a cv shaft. Is there still a need for shims??

 

[XJsurf]

I have went thru the same thing as you and finally settled for what I have posted. I see where GoJeep is coming from with his thoughts, but I'm with you and think if you have drop in the TC it isn't that much. If you have a driveline specialist in your area they can explain it in easier terms and show you on the rig what you will need to do. Our local guys don't charge for that service.
You probably have a good grasp on what you need to do. Try it then run it, and if it still vibrates alot swing by the driveline shop.

Hey I had to show my pics from this weekend on the RTI. I know everyone says articulation is over rated, but I was in the 800s and took second place on our rock course. XJs did real good Saturday. I'll have video link soon too.
This is from a Daily Driver also !

Boise49ers,
I have to ask is that rhino liner on the rear quarter panel. That looks nice!

 

[boise49ers]

Boise49ers,
I have to ask is that rhino liner on the rear quarter panel. That looks nice!

14 gauge steel painted with dulicolor bedliner. $7.50 a can at Wally World. The front clip , bumpers,the rock rails and inside the wheelwells are all painted with it. I love it, because it sands out and recoats real easy to match back up. Pretty durable too !