My vehicle specs:

86 SAS 4Runner with 83 toyota rear springs up front. 2.5" drop hanger. 5.5" shackles. Dual case setup with Marlin crossmember/skidplate. Low pinion elocker in front axle. U-joint shaft with long slip.

I've put about 250 easy miles on the rear to break the new gears in. No death wobble with this setup. Just a slight shimmy @ 40mph. Don't know caster angle because I haven't taken it in to the alignment shop yet.

So, today I disconnected the rear shaft so I can run it in FWD to break in the front diff gears. With the steep angle on the t-case flange, I can only go 10mph max--pushing it with lots of vibes.

Without cutting/rotating the knuckles, will shims fix the angles? Here are some pics...








Too much angle on the t-case flange u-joint...

Do you have a CV on the front driveshaft? If not, I'd do that. But a clearanced CV on there and you should be good to go.

You can use shims to correct the pinion angle up to the steering caster angle limit. You would need to see where your caster angle is now in order to see how much correction room you have:
- http://www.4crawler.com/4x4/ForSale/Shims.shtml#FAQ1

Assuming the truck is driven on the street, good steering would be more important than pinion angle.

[color:"red"]No CV. Just U-joints at both ends. I think a CV at the tcase end would work, but I know there will still be vibrations. At this point, I'm looking for the cheapest fix-and that's shims.
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[color:"red"]Truck is driven on the street daily. I'll get back with you in a few days after I get my caster angle. [/color]

You need one of these...

to compensate for the angle, you have 3 choices:

drivetrain lift to lessen the angle of the t-case flange

CV driveshaft

degree shims


honestly, the degree shims will probably not get you anywhere near where you need to be, plus to match the backward sloping angle of the t-case flange, you would need to point the pinion to the dirt.

i would go with the CV shaft.

otherwise, deal with it. if your truck is low speed wheeling only, its not a big deal. i have a similar setup but with a single t-case and i run std. u-joints at both ends.

for proper gear break-in, swap the front and rear 3rds

I don't think you mean to say drivetrain lift as in make the t-case higher right? ...In his case, it would be drivetrain drop. <img src="/forums/images/graemlins/wink.gif" alt="" />

You can affect the t-case flange angle a bit if you raise just the t-case end (leaving the egine at stock height). About 1 degree of angle for each inch one end is lifted relative to the other. This will affect both front and rear flanges, lowering the front angle and increasing the rear angle.

I don't have a body lift on my truck. Looking under the drivetrain tunnel, there's less than 1" before the top of the T-case hits the cab. Also, my rear end is dialed in and I don't want to mess with angle. Even if I wanted to, I can't without a body lift or new crossmember.

So, I think I'll put a CV on. First, gotta clearance the IFS CV and take it in to get it weld on.

Off topic--The passenger seat bracket cable assembly broke today. It finally let go after 20yrs of use. Local prices were from $40 to $50 without the nearly 9% tax. Just ordered one from 1sttoyotaparts for $30 shipped. Couldn't be happier. <img src="/forums/images/graemlins/smile.gif" alt="" />

nope i said what i meant. if we were talking the rear d-shaft, a drop would lessen the angle. since we are talking the front, a t-case lift will lessen the angle since from the factory, the drive train goes downhill as you go rearward.