Ive lowered my truck 3 inches in front with drop coils and 4 inches in the back with drop hangers and shackles, My truck is a ext. cab with a single aluminum drive shaft its a 2001. My problem is I have a vibration between 50 and 55 way worse under a load, I installed 4 degree shims between the leaf spring and axel. And I also put in new ujoints. this helped out a lot but you can still fill it under a load, barley but it is still there. I thought I read where someone used a 6 degree shim. If there is any of my fellow f-150 enthusiast out there who have already been down this road please reply.

 

I would say that it is sstill in the drive line angle. We stretched a friend of mines Lightning. Meaning we found an extended cab truck in the junk yard and got the parts we needed to stretch his. He had the same problem until we put an angle meter on the drive shaft and found that the angle was off. Once the angle was corrected....smooth as silk. You need to find out what angle your truck drive should be at.

 

Im pretty sure its still in the angle,if anyone has already lowered there truck, What degree shim was used and which way was it shimmed axel up or down , right now i put them in where the front of the axel is shimmed down. when i lowered the truck it looked like the axel was tilted up to much.

 

I got the 6 degree shims in today,installed them in the truck and couldnt wait to drive it , went though the gears and no vibration!just what the docter ordered. hope it stays like this.

 

That's great!!! I had a hunch that was going to be it.

 

I have a question, what company did you get your drop kit from.?
Also how long did the install take?

 

if you can get a truckin mag,do some shopping there is a lot of diff between prices, If you do a 3/4 drop you have to replace the shocks too so price coils for the front and drop hangers and shackles for the back plus shipping and handling get a total price for everything, Ive ordered alot of stuff from truck performance .com , stylin concepts,godfatherscustoms, so far i havent had any trouble with any of these. The worst thing about the install is the removel of the factory rivets when you replace the hangers.its all pretty straight foward a good mech. with proper tools could do it in 4 to 6 hours or may be a little more. its a good allday job for most shade trees. any further help you may need e-mail me at dbalser@worldnet.att.net