Need Advice,
Just recently installed Belltech 2" lowering shackles on my 01 2WD Supercrew. The 2" shackles almost leveled the Supercrew and am pleased with the results, ride is still good.
Here is the problem, between 55 and 62 mph there is a slight roar do not remember hearing this prior to installing the shackles. If you let off of the gas the roar goes away so I am not sure if it is drive train noise or muffler noise.
Thanks for any advice.
JAG

 

Sounds like you need pinion shims. I think yours already has a small shim. Some guys have had success by turning those around to face the other direction. You might try that first.

 

Any advice on how to change these out? I assume I need to drop the axle and replace the shim that is under the leaf springs. Which way would the shim face?

 

ttt....

 

Never knew a "roar" noise indicating the need for pinion shims, but if the truck is vibrating/shimming at a certain speed, after the shackle install, then you need pinion shims (sometimes you do not with just 2 inch drop shackles but will need them with 3 or 4 inch drop with a higher degree shim with more lowering of course). This is usually obvious if you look where the rearend ("pumpkin") connect to the U joint/driveshaft. This area should be straight. If not, and or the truck vibrates, you need pinion shims.

The pinion shims are shaped like a wedge or skinny triangle. The wider end points toward the front of the truck.

Since the tire is off, at least your axle should be jacked up. You then loosen the 4 nuts on the two u bolt clamps that hold the plate down on the TOP of the leaf springs. I have to always put a jack and or jack stands under the leafsprings and lower the axle down some to get the space open between the axle and the BOTTOM of the leaf spring pack. You place the shim BETWEEN the plate on the axle and the BOTTOM of the leafspring pack.

You can get a new bolt that goes through all the leafsprings and keeps them together. This bolt has a longer head or spacer that will go through the center of the shim and keep going through the center of the BOTTOM plate on the axle. This ensures that the shim stays were it is placed under high torque. However, I have not completed this. Some complete lowering kits do no even come with these leafspring bolts.

 

Hotglass.... I have the same truck you do with a set of 2" DJM Drop shackles on it. After my shackle install, I ran into the same noise issue you're reporting. I totally cured the noise with a set of 2 degree pinion shims (from Belltech). Follow the install instructions that Iron horse listed in his post and you should be good to go.

-Mike-