SOA on a LWB.... do I need to address the driveline?

[BIGHEEP]

I am going SOA on my 88 LWB MJ and I was just wondering if I am going to have to do anything to the drive line such as SYE, T-case drop, or axle shims?

[jage]

As I understand Tcase drop is to improve driveline angles in short shaft vehicles- so that shouldn't be an issue.

 

I'd say SYE because you're increasing your travel, and the DS may slip out of the tcase. I've seen it happen on a YJ on the trail. Not the worst thing I've ever seen so you can probably get by without it if you want to be cheap- do it if it falls out.

 

Axle shims are for driveline angle as well, so if you're welding new perches you don't need to do this.

 

One codicil to all this- if you do double-cardan when you do the SYE the pinion should align differently than if you do single. I think single is matching angles from Tcase to DS and DS to Pinion and double is point the pinion at the Tcase. But don't quote me... it's somewhere in one of these threads.

[jage]

this isn't quite what I was looking for:

http://www.comancheclub.com/forums/viewtopic.php?t=35&highlight=single+double

[BrettM]

You don't need any driveline mods, though you may want to get the driveshaft lengthened a tiny bit. If you're putting in an axle with a longer pinion you won't even need that.

 

Definitely change out the u-joints in the current shaft though, they often self-destruct if you change the operating angle on them.

 

My shortbed MJ has been at 6-8 inches for several years and a couple cross-country drives. It is even doing great with 6 inches taken out of the rear wheelbase. Your longbed will only fare better.

[Regger]

I was running 6" on my LWB which consisted of 4" leaf packs and a 2" shackle. The shackle actually made the driveshaft angle better because it rotated the pinion up and I had very minimal vibrations if any...

 

And Jage, yes with a double carden/CV you point the pinion at the t/case minus 2* (for axle wrap) and for single u-joints, the pinion and the t/case have to be parallel minus 2*.

 

A SYE won't be need for this lift, but if you are concerned about driveline angles, you can buy a slip yoke that mates to a double carden. This saves you some money from buying a SYE kit, but you would still have to get a new driveshaft...

 

but all in all, you really shouldnt have to worry. Just set your pinion angle good, and hit the trails!!!

 

HTH

Ryan