How much will a 1.5" lift shackle change my pinion angle?

Currently have rusty's 4.5" rear springs (sye too) and a shim of unknown size, but the pinion pointS just a hair below the T- case output, right where it should be (1-2* below the driveshaft). I currently don't have any noticeable vibes.

Not sure on the size of the shim, it was already on the vehicle when I bought it...looks to be 4* or so.

If I put 1.5" shackles (3" longer than stock), this will most likely tilt the pinion up a few degrees, but does anyone know about how much? I forgot all my geometry since high school.

Thinking I may need to remove the shim entirely and start from there.

Also will be going from a D35 to a D44 at the same time...but both with stock spring perches...what do you guys think, remove the shim entirely or start off with something like a 2* shim?

you should be fine, ive went from a 1.25 to a 2.5" shackle before while keeping my 6* shims with rustys leaf srpings. the only real way to know is to measure and drive it. unless somebody on here has noted there changes with 1.5 shackles

with the stock d44 perch and a shim you will probably get nasty axle wrap

skyjackedxj96 said:

you should be fine, ive went from a 1.25 to a 2.5" shackle before while keeping my 6* shims with rustys leaf srpings. the only real way to know is to measure and drive it. unless somebody on here has noted there changes with 1.5 shackles

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Thqanks yeah I have an angle finder.

Just was looking for my best starting point since I will be swapping axle while adding shackls and the shims will be easy to change while I have it all apart.

cal said:

with the stock d44 perch and a shim you will probably get nasty axle wrap

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With a shim? Why is that? Are they shorter than the 35 stock perch?

cal said:

with the stock d44 perch and a shim you will probably get nasty axle wrap

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I'm no expert, but I wouldn't worry about a shim causing axle wrap.

Roads said:

I'm no expert, but I wouldn't worry about a shim causing axle wrap.

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Depends on the shim. Alot of them are flat on one surface with a slight curve on another .. procomp, skyjacker i think.. just off the top of my head. I've seen it as a problem a couple times, once on my own rig.

cal said:

Depends on the shim. Alot of them are flat on one surface with a slight curve on another .. procomp, skyjacker i think.. just off the top of my head. I've seen it as a problem a couple times, once on my own rig.

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Nah I will be going with one from RE (steel of course) which is flat on both sides....that is, if I need one.

I had a 6.5 inch lift with a 1.5 inch shackle when I ran 35's on the road. I used a 3 degree shim to minimize the drive line vibes. That's on an 01. (D-44, 231 W/AA HD SYE)
Since then the shims broke so I pulled them. Now It's shimless but it's also a trailer queen now too.