Rear axle shimy

[caleb22]

We added a 4" ord shackle flip to my 89 Blazer, TC SX8000 shocks and TC front springs. Below 15 mph no vibration. 15mph to 25mph we have vibration in the rear. Do we need to add shims to the rear springs for proper shaft pinion angle?

 

[79k20350]

WHen you do a flip it point the pinion right at the tcase. this is great for a cv shaft, not good for a regular shaft. get a angle finder (like 10 bucks and home depot) the pinion angle and tcase angle shoul d be with 2-3 degrees of each other. youll most likely have to shim the pinion down a lil

 

[caleb22]

Would a 1" zero-rate from ORD in the rear help?

 

[Jishory]

zero rates would bring the axle back, but it would also give you more lift that would be bad in your situation... yesterday i did a free trick to gain some wheelbase, i just drilled out my spring perches and spring plates so the center pin would be offset moving your axle back, free and it would help a bit but i wouldnt count on it fixing your problem though and it might pull your slip yoke out, i think what dleroy was explaining to me while he was doing it to his burban was to match the angles the u-joints are are so tip down your pinion to match the angle your top u-joint is at... dont quote me on that though, ill let somebody else chime in and correct me here if im wrong

 

[79k20350]

what do you mean, he said nothing about wheelbase... a zero rate doesnt have to move the axle. To fix the problem try lowering you tcase . take the spacers from above the frame rail and put hem below, this will point th back of the tcase down (equivilent to shimming down the front of the pinion) if this works get some heavy wall 1"x1 1/2" or 2" wide steel tube and use that as a spacer.

 

[steve_kibbe]

I totally forgot about making the angles of the ds the same. Bill, I have the tool(anlge finder) to check it.

Thanks for reminding me

 

[79k20350]

oh so you were the "i know what im doing helper" i guess we have you to blame it all on then

 

[steve_kibbe]

yea, it was me. I'll take the blame. I'll also fix the problem

 

[79k20350]

at least your willing to do that...