Pinion Angles @ 4.5" lift

[BrianJr]

I am getting ready to install a RE 4.5" Super-Flex lift on my stock 1999 XJ. The research I have done indicates that I have about a 50/50 shot of eliminating driveline vibes with the t-case drop that is included in the lift. Otherwise I will need a SYE. It has been recommended that I install the lift with the t-case drop and see how the XJ drives before ordering an SYE. I have two questions:

1. How many degrees did you have to shim your rear axles with the 1" t-case drop? (to get the pinion angle to match the t-case output)
2. How many degrees did you have to shim your rear axles with a SYE and RE 4.5" lift? (to get the pinion angle to point at the t-case)
   [/list=1]
   The reason I ask is I am also installing a new rear axle. My plan was to weld the spring perches on at the angle for question 1. I can then buy shims to get to the second angle (question 2) if I need an SYE.
   
   I really need to get a good idea about question one. I have the replacement axle and need to get as much done on it as possible before the lift goes on. I am borrowing garage space and don't want to overstay my welcome. So I want to get the spring perches welded on before the lift arrives so that everything is ready to go.
   
   Thanks,
   -Brian
   
   BTW: In case it matters for some reason the current axle is a Dana-35 and the new one is a Ford 8.8"

 

[ChuckD]

I have not used shims but found when I added my rear shackles, Daystar Specials, it moved the pinion up. It worked well with my extended yoke and 1" TC drop and also has worked well so far with my AA SYE.

I don't know how much of a change it made, but if you plan on latter adding shackle to your rear springs. Be aware that your rewelded perches may not be where you need them.

 

[BrianJr]

That is a good point. I didn't mention it but the RE 4.5" Super-flex kit comes with 3.5" leafs and a 1.25" (?) shackles.

-Brian

I have not used shims but found when I added my rear shackles, Daystar Specials, it moved the pinion up. It worked well with my extended yoke and 1" TC drop and also has worked well so far with my AA SYE.

I don't know how much of a change it made, but if you plan on latter adding shackle to your rear springs. Be aware that your rewelded perches may not be where you need them.

 

[trekker]

I have a 91 with 4.5", TW driveshaft, and JB SYE. Tom Woods set me up with 6* shims per my measurements and my angles are perfect.
Your results may vary, just wanted to give you my experience.
T

 

[BrianJr]

Thanks. I'm trying to find out what worked for other people so your response was just the sort of thing I was looking for.

Anyone else?

-Brian

I have a 91 with 4.5", TW driveshaft, and JB SYE. Tom Woods set me up with 6* shims per my measurements and my angles are perfect.
Your results may vary, just wanted to give you my experience.
T

 

[ChuckD]

That is a good point. I didn't mention it but the RE 4.5" Super-flex kit comes with 3.5" leafs and a 1.25" (?) shackles.

-Brian

I used these shackles with both my Re1462's and my built up stock leafs. The pitched the pinion at about the same angle. I also used this set up on two different axles, an 87' D35 and an 87' D44.

 

[2xtreme]

I would be shocked if you could make a RE 4.5" lift work on a newer xj without the SYE. Personally I would plan on the SYE and weld the pads accordingly. With the 6" RE kit I installed recently and the SYE kit the rear axle did not need shiming at all. and I would guess that with the shackles and aal you should be pretty close to in line with the transfer case. However, if you use the shackles and aal and a drop kit I would guess that you are going to want to shim significantly to get the angles at both ends of the rear driveshaft similar.

I think you are on the right track getting peoples feedback, but I suspect you are going to want to plan on the SYE rather than the other way around.

Any idea how long the pinion on the 8.8" compared to the D35? How low is it also? These dimentions will make a huge difference for your input.

Michael

 

[What Rd]

I second the notion of planning for the SYE straight out of the box. I'd also suggest you not weld up your spring perches until you have the springs and either TC drop or SYE in place. It'll only take a matter of minutes to burn them onto the tubes once you have things lined up the way you want. You're playing with too many variables to have a fair chance of having everything come out right if you fix them ahead of time. Consider that in addition to the differences between the D35 and the 8.8 (don't forget the axle tube diamter is different also, as well as the pinion height and pinion length, and the flange that the 8.8 mounts up with), XJs (all Jeeps for that matter) are notorious for having considerable variation from one to another, even among model years.
I really think you're better off doing it all at once. Just some thoughts. Good luck.

 

[BrianJr]

Based on what I had read about late model XJ's I was going to just get a SYE. However, the two most experienced people I knew said that I had about even odds of getting away with just the t-case drop and shims.

Are the pinion angles really going to varry from XJ to XJ? I know that suseptibility to vibrations did but a lot of things factor into that. However, I thought that the pinion angle on one 97+ XJ with a t-case drop would be the same as the next... Was I mistaken?

 

[Zebra3]

I had Rustys 4.5 lift with a 3/4 inch spacer and stock isolator and used 1995 Chevy 1/2 ton shackles with the 4.5 full spring packs out back which gave me a full two inches of drop. With the TC drop that came with the kit put my drivshaft angles perfect! No vibes whatsoever! No SYE.

 

[MuddyJeep]

What year was that in Zebra?

 

[Zebra3]

A 96 Sport. 4dr.