bombout800

So I've been recently trying to learn about my suspension and getting to know what I have a little better. I've bought a angle finder and have the tools to adjust my arms if need be. I adjusted my flex joints, whomever put the lift on obviously torqued everything in the air and did not adjust or let settle on the ground first. The ride was noticeably better.

My next question is this when putting the angle finder on my axles I think It was about 88 degrees. So I know adjusting the control arms to take away some castor is goin to be needed and this should give me a better pinion angle closer to 90 degrees. I'll add pictures of the readings. Next thing... When adjusting my lower control arms in to pull the axle back and pinion up, I want to be around or as close as I can get to. 4.2 right?? Also pinion angle as close to 90 degrees right? So say I get the pinion as close to 90 as I can with castor around 4.5 and it rides terrible. What do I do?? How do I know my driveshaft is okay.

Well where I'm at right now(as you'll see in the pics) my front driveshaft is probably hating life . Any help is appreciated and I am doing my research but it would be nice to know what route to take if I get it all dialed in and need to readjust for ride or longevity. Will I also need to recheck toe?

I think my pinion angle is right at 88 and my castor is around 7 or so. The other pic is I the rear axle which seems to be straight in line with the angle of the output of the trans. That's just the degree it's at.

bombout800

Btw I'm on 4" with 35s adjustable control arms.

Sahara Lee

I have a 4" lift and 35s (actually 315/70R17) too. My lift manufacturer recommends 4.6 degrees caster +/- 1.0. Although I don't have adjustable control arms, I do have Rancho control arm correction brackets. My caster is about 5 degrees and the steering and handling are great.

You can't adjust both pinion angle and caster without modifying the axle tube (rotating "C"s). To me, correct caster is more important than pinion angle. Caster affects steering while pinion angle is not as critical IMNHO because as a rule, we don't drive over 45 mph in 4WD. The front drive shaft has no load on it at higher speed so it won't wear prematurely even with a 10 degree (pinion shaft to drive shaft) angle.

Going with an after-market drive shaft is supposed to help. I've looked at the design of the dual-Cardan CV and frankly I'm not impressed. Why doesn't someone just make a front axle with 2 true CV joints like the stock rear drive shaft has but able to operate at an even higher angle? That would be the bomb.

BTW - The pictures below are at maximum travel, full extension. The only time this should happen on the road is if I'm pretending to be General Lee instead of Sahara Lee. On my 2010 Sahara Unlimited with automatic the front drive shaft doesn't rub and in spite of what the last picture looks like, the CV at the TC still rotates freely without damaging the boot.

BBTW - The XClinometer app for Androids (also available for iPhones) is excellent for checking angles.
http://download.cnet.com/XClinometer...-75623111.html

bombout800

I'll have to call and see what mine recommends but I would imagine the closer to 4.2 the better. I mean adjusting the castor will roll the pinion closer to 90. My driveshaft does rub and just from flexing with the sway bar links connected it's rubbed the rubber boot off and I have a few Knicks in the slip yoke as well. I'm going to try and shoot for around 4.2 to 5 deg. And see where I get. I have correction brackets on the way but I want to play with it and learn a little bit. Never hurts to get experience. Plus, I'll more than likely have to readjust when I get the brackets anyways!

bombout800

With me setting my castor correctly I'll regain my correct my pinion angle. But I guess the post itself was meant for if I adjust to 4.2 deg and something doesn't feel right what should I do ? Go straight to 5 and work it back until it feels right? I'm also installing my Evo draglink flip this weekend. So everything should feel nice and tight after that and the correct castor, along with the correction brackets

GunDude

The front drive shaft has no load on it at higher speed so it won't wear prematurely even with a 10 degree (pinion shaft to drive shaft) angle.


It may have no load on it but, it is constantly turning, wether in 4x4 or 4x2 mode. So, it does matter if the castor is set at 10 degrees.

olyelr

You shouldn't really be concerned about the pinion angle up front. You can only adjust one or the other up front (between caster and pinion angle), and caster is much more important. Unless you actually rotate the C's on the axle tube, they will both be adjusted at the same time. So you need to look more into the caster rather than the pinion angle.

Typically, installation of a lift will lessen the caster, which makes for flighty steering at speeds. This is corrected by EXTENDING the lower control arms or SHORTENING the uppers. Doing this will not make the pinion angle better. Don't quote me, but I think somewhere around 5 degree's caster is where you want to be at that lift height.

Sahara Lee

Not to get too far afield of the OP question, but...

Here is a Dana/Spicer drive shaft installation instruction for heavy vehicles:
http://www2.dana.com/pdf/J3311-1-HVTSS.PDF

Some things that I find interesting in the write-up:
1) Given that I am running 315/70R17 Duratracs with 4.88 gears, my drive shaft is turning 4000 RPM at 80 MPH.
2) Dana does NOT recommend "solid" drive shafts above 3000 RPM. Only tube type shafts are recommended.
3) U-joint angle should be at lease 1 degree (to prevent needle bearing "brinelling") but should not exceed 3 degrees.
4) The maximum angle recommended by Spicer engineers at 4000 RPM is 4.2 degrees. (5.0 degrees at 3500 RPM or 70 MPH for me.)
5) I know the write-up is by the Dana Heavy Vehicle division but it should work for Jeeps too since Spicer 1310 is included.

After reading this I need a

bombout800

We'll in my case I'll need to either extend the uppers or pull back the lowers. I'm thinking that i will extend the uppers this time. My axle seems to be centered just fine and my toe in seems to be around 1/16" or so. I'm going to re check my center as well as my toe after extending the uppers. Should ride a little better and put my pinion angle a little higher. My driveshaft seems really low at the tcase. As stated earlier I'm going to also be installing my Evo draglink flip. Hopefully this all goes well.

tklein42

OP keep us updated. Im going through the stages for my first time and would rather not waste my money on minimal gains Btw for your time