shimming axle to help pinion angle

[richingalveston]

I have a dana 60 and 14 bolt with a 5 inch lift using zero rates.
I have to move the axles back to stock location. currently have front moved forward an inch and back moved back an inch.
Since I am going to take it apart again, I want to shim both axles to help my pinion angle. I have CV style joints at the t-case and everything is running close to its limits.

I plan to take my zero rates to a machine shop and have them milled so that I do not have shims above or below the Zero rate.

How many degrees can I go on the front and back. I assume the back can go as far as you want or will something starve for gear oil.

The front is the question with the Dana 60. I assume there is some camber or caster. not sure which built into the axle. Is there a point which you should not go past or it will affect steering or tire wear.

Not sure what the limits are if there are any. 10 to 15 degrees would definitely make a difference.

Thanks for your input.

Rich

 

[Chaski]

I wouldn't mess with the front at all. If you want to spend a bunch of money you could cut and clock your knuckles, but that is a lot of trouble. Changing your front pinion angle without correcting caster will not wear out your tires, however it will cause death wobble and probably make your hands and feet sweat trying to not die while going down the road. There is no other way to gain clearance in the front without some scary caster steering geometry. Now in the back if this is the same rig in your signature you probably have a pretty weird pinion angle with your shackle flip. On my buddies m1008 he is running the ORD 4" flip with no shims, and his pinion is pointed above his t-case. On my K2500 I have the 2.5" flip, and 1" zero rates, which I milled 3 degrees. I did this to drop the pinion back down closer to stock, drives nice, but I have a nice long driveshaft. With the 4" shackle flip your I'm guessing your pinion is pointed at your transfer case, which is what you want with the cv's. Maybe go buy a magnetic protractor and check where you are at? I can tell you 10-15 degrees is WAY too much, and probably not possible on a 1" thick block...damm trigonometry. Get a protractor, measure what it would take to point the pinion right at the transfer case and I'll bet it is more like 2 - 3 degrees.

 

[Westech]

Re shimming your front axle will NOT cause death wobble . With a 3" lift I used 2* shims in the front of mine. I would use 4* with a 5". Death wobble is due to worn kin pin bushings/ hold down springs end of story.

 

[Recovry4x4]

Adjusting to zero or negative caster will create an ill-handling vehicle. Whatever term you give it, it won't be fun to drive. It's a simple matter of geometry. Sorry Richingalveston, I can't give you exact degrees off the top of my head. Rear lift height also effects the caster angle. Best to use an angle finder or even a plumb bob to determine what you have to work with.

 

[Skinny]

Re shimming your front axle will NOT cause death wobble . With a 3" lift I used 2* shims in the front of mine. I would use 4* with a 5". Death wobble is due to worn kin pin bushings/ hold down springs end of story.

To a point...

When you remove positive caster, it creates instability which any smaller disruption on the steer axle while driving could cause a severe death wobble. Positive caster actually lifts the front of the vehicle when the tires turn left or right. Removing caster will cause not as much lift which means no oppposing force to push back on death wobble influences. Worn parts obviously cause this to happen as well. If anything you want to increase positive caster with larger heavier tires to negate this effect.

I would agree not to touch the front end unless you are going to shim for more positive caster or do a full out cut and turn to the knuckles. On the rear, just buy new spring perches, chop what you have off, set them in place, jack the pinion till you get the desired angle, then tack them in place. Shims will do the same thing but aren't as solid. You will probably need to replace shock mounts if you are rotating the rearend at all. With my shackle flip, the mounts come awfully close to the shocks. As far as lubrication, should be good. You can always buy a new diff guard with an oil fill plug that is higher or just fill the diff through the breather line which is really fun!

Just curious, what problems are you having? I would think with a CV rear driveshaft and a shackle flip, your rear shaft would almost be perfect. If not, only requiring a few degrees extra on the rear axle.

 

[richingalveston]

I have no problems in the rear, the shackle flip gives it just enough it would not hurt to have a slight bit more angle. It is pointing at the oil pan and not the t-case but it has no vibration or bumps due to the cv hitting its stops.

My front driveshaft is longer than the rear. My t-case and transmission is 2.5 inches longer than stock. I have the t-case clocked almost flat and would have to rebuild the cross member to clock it down. There is only 1/2 clearance on the top of the t-case so I cannot raise the back any further to help the front.

The front drive shaft is at its limits when the axle is hanging on the springs, there is a slight bump in the CV joint. Just trying to get some extra room.

I have the axles moved an inch and I have the High steer and tie rod. The tie rod hits the pitman arm in certain situations. If I move the front axle back 1/2 inch it will fix the problem. I am going to move the back axle forward so that I can trim the front of the back fender and not the back of the back fender.

Since I was going to take it apart, I was going to see if I could improve the front axle angle.
I will probably add limit straps if I have to. It only happens when there is no weight on the axle. does not seem to be an issue when one tire is up and other is down.

Moving the axles back to stock will allow me to build the drive shafts the same. They will be close enough in length that I can make them interchangeable. Could not due this with the current set up.

I already cured my death wobble with new front hubs. I chased it for about 6 months before doing new hubs and rotors up front.

 

[Skinny]

I think you will he unhappy moving the front axle back to the stock location. I would clearance the front CV or buy a high angle CV from High Angle Drive line.

 

[richingalveston]

I need to move it because it hits the pitman arm. It only needs to move back 1/2 inch however the zero rate is either 1 or 1 1/2. It does not allow for moving the axle only 1/2 inch forward so it puts me at moving the axle back to the stock location.
I was considering making custom zero rates with about 5/8 inch offset and built in shim because that would be perfect, I may skip the shim but still make a custom block.

I have to take it apart one more time so I wanted to cover everything I can. When it goes back together it will have Hydro assist steering also.

Thanks for the input
rich

 

[Chaski]

That is what 1" zero rates look like when cut to three degrees, if anyone was curious.

 

[richingalveston]

Looks like that is on the rear, does your front have them also and did it affect steering?

 

[phil2968]

If you have one u joint and one CV joint in your shaft you will have drive line vibration. U joints are meant to be run in tandem. The following video explains it quite well. Note what happens to shaft speed when only one u joint is angled. Same would happen with a CV and u joint combo.
http://youtu.be/gmV4qwLfOMY

 

[richingalveston]

It is not the same with a cv joint and u-joint. The cv joint or 'constant velocity' joint does not speed up and slow down like a highly angled u-joint. You will only get that in the u-joint that is at the differential and it gets worse with more angle. Thus that is why I am trying to shim my angle up in the front. I do not have any vibrations but I am at the limits of my CV joint when my axle is at its lowest point.

Thanks for the post, that explains two joint geometry very well.

 

[phil2968]

So you said you have CV at the transfer case. U joints at the axle then? Trying to get rid of their angles? Just trying to figure out your set up.
A CV on one end of the shaft supplying the angle means a u joint on the other end must be straight. Is this your goal?

 

[richingalveston]

yes, I am trying to reduce the angle on the U-joint at the front axle. Have front and rear axles with cv at the t-case. rear axle is ok. front angle could be better but does work. I roughly measured it with a T-square and 4 to 6 degrees would probably get it as strait as the rear axle.

just not sure what that would do to my steering on the D-60 front axle I have in my 1009
I will be taking the axle loose again soon to and I would like to do all I can while I have it apart and I was considering having My zero rates milled.

 

[Chaski]

I don't a run a shim in the front. I only have about 3.5" of lift. The front end has about 8 degrees positive caster in stock form. I wouldn't rotate it in the negative direction more than three degrees from stock keeping it around 5 degrees positive

 

[olly hondro]

From a local shop :

".....[FONT=&quot]thing I would do is look at the caster angle of the steering knuckle, 5-7 degrees is what you want...But you need to look at pinion angle also, if you put degree shims in, you mess with pinion angle. There is an adjustable lower eccentric available for the 60.

Third thing is camber angle.. The housing may be bent, or the lower knuckle bearings are history.

Toe is the last thing, about an 1/8" toe in."

[/FONT]

 

[Skinny]

This is a simple throw money or labor at it kinda fix. Leave your front axle alone, position it where you need it in order to clear tires or steering linkage...that is perfectly fine. If your front driveshaft is not vibrating from operating at an excessive ujoint at the axle end, you are doing pretty good because the only way to fix that are not worth it or really expensive.

-lower the truck
-clock the tcase down (NOT a tcase drop)
-cut and turn the front axle
-have a custom high pinion D60 installed

This leaves you with what it sounds like is the only issue to resolve, the tcase front driveshaft CV operating angles. You WILL have to clearance it either yourself which can crudely be done with a cut off wheel to gain a few degrees which is what my 4" lift required at max droop or to buy a driveshaft that has a higher operating angle like this one: http://www.highangledriveline.com/1350cv.html

 

[86m1028]

Since you have the Ord magnum, why not clock your tcase down some ?




Can you post a pic of your frt driveshaft angle at the Dana 60 yoke ?

 

[richingalveston]

I finally got the chance to take some actual measurements of my drive line angles using a torpedo level and speed square.
My front steering knuckles have 9 degrees angle up towards the front.

My front pinion angle is 5 degrees up toward the t-case. With each degree of shim the pinion will raise 1/4 inch. I believe 3 degrees would make a big difference in getting my pinion in line with the t-case. (I was way off thinking 10 to 15 degrees was needed),

I do not have the t-case in the vehicle so I could not get drop and distance between the t-case and front and rear u joints.
I know my front drive shaft is 3 inches longer than the rear.
I was able to figure the angle of the t-case because it is still mounted to the cross member. A very good estimate of my t-case angle is 4 degrees. The rear output is 4 degrees down and the front is 4 degrees up.
The rear axle pinion angle is 13 degrees and points directly at the output flange on the t-case (could not get much better).
The transmission and t-case should be installed next week and then I can find the drop and distance on the drive shafts. I can then calculate my CV angle and u-joint angle.

I believe I am going to shim my front axle by milling my zero rates 3 degrees. This should give me 6 degrees on the steering knuckles and 8 degrees on my front pinion angle.
I have to move the axle back 1/2 inch to fix the issue with the high steer tie rod hitting the Pitman arm.
Since I have zero rates I will a have to move it 1 inch which puts it back to the stock location (there is not a 1/2 adjustment option on a ORD zero rate).

I have a shop that will mill my existing zero rates for about $75.
In order to re-clock my t-case, I will have to rebuild the cross member that has already been powder coated. It will cost more and take a lot of time.
If I still need a little help, I will clearance my CV joint myself to

I am just trying to fine tune the drive train since I have to take it apart and put it back together one more time. I can run things as they are and will only have a slight vibration every time the front suspension is at full drop which will be rare, but since I have the opportunity, I would like to fix all issues that I can.

I currently do not have an issue with the rear axle and since it will not harm anything, I am going to move it back an inch to allow for front and rear drive shafts to be interchangeable. The front will only be one inch longer which will be close enough for a spare drive shaft to be made that will fit either the front or back.

I would like to thank everyone for the input. I am close to getting my 1009 back on the road. My next steps are to get the transmission installed. Move the axles and mill the zero rates. Have drive shafts lengthened/shortened and then install the OPTI shift trans controller which should be on its way.

Rich

 

[Skinny]

Rich

I don't want you to take that is criticism, you are going to regret that move. If anything you would want to sacrifice pinion angle to increase positive caster. Stock caster is OK with bigger tires, a few degrees extra like 3-5 degrees is awesome. It is going to keep the truck tracking straight with heavier wider tires and will reduce the front axle from developing death wobble when hitting pot holes. Yes death wobble typically occurs due to worn out parts or defective tires/balance issues but the shopping cart wobble tendency can happen with reduced caster.

I think you are at the point of a cut and turn on the front knuckles or just leave it the way it is. Just my opinion and like the ol' saying goes...