HappyTrails

OK, I had a RE 3.5" Superflex professionally installed a few months back. They did a nice job. But it turned out to be more like 5" as confirmed by the common lift height methods. Reading the fine print of the RE paperwork, the 3.5" RE Superflex "may be has high as 5". OK, Thats what I got. Not complaining.

But it necessitated a lot of driveline mod I was hoping to avoid. But, again, not complaining, since the upgrades are sensible and worth the money.

At 5" lift the rear driveline operating angles were 12 degrees front, and 9 degrees rear. Ouch. Not only were they mismatched, but they were way over what safely works. 7 degrees max is the wisdom on that from what I read. Over that is an invitation to mechanical destruction and wallet evacuation.

So, I installed a RR SYE kit and followed it with a Tom Wood's C/V driveshaft. I used 6 degree leaf spring shims to tilt the pinion up toward the TC. The aim was perfect, as confirmed by my angle finder after installation.

Result is this, on the rear shaft the rear operating angle at the diff pinion is 0 degrees (vehicle unloaded). Front operating angle behind the TC is total of 10 degrees. That is split by the two joints in the double Cardan. So each is only operating at 5 degrees, well within the 7 degree max per joint.

Rolls down the road smooth as a 59 Buick.

Front drive shaft has TC operating angle of 13 degrees at the double Cardan joint. Thats 6.5 degrees per joint. Within the 7 degree max. The lower diff pinion joint is a 3 degree operating angle. Not the best, but not easy of tweak out without messing up alignment angles. So I will just live with that and hope the pinion bearing stays happy despite the mild abuse.

So there you have it. People are always asking what such and such lift will do to this and that. Just told you my story. Yours may be different.

This was on my 96 Sport two door 4.0L and AW4 with NP231 and D35 w/ABS rear axel. It rides on 31 x 10.5 x 15 Goodyear Wrangler Silent Armor tires. Lightweight with no rack, hitch, winch or heavy bumpers. Empty weight per the book and stock rollers is only 2900 +/- lbs. Probably why it sits a bit high.

BTW, I looked into substituting a Grand Chero or other driveshaft on the rear, but none I looked at would fit, or they had some real different front fitting. And the XJ front shaft was just too short on extension to safely use. I don't regret spending the 300 iron men to get a proper one from Tom Woods. I try to avoid using other old stuff of unknown service life and abuse when the component is critical to getting home and having a safe day. Besides, new stuff just looks cool.

sweeper

Looks good!