I've got the rear of my truck dropped with a flip kit (not DJM, not adjustable) and shackle at the 1" hole. When I launch under full throttle and hit a bump, or anytime spraying nitrous, my crossmember will hit either the vapor canister bolt, or one of the crossmembers underthe truck. Does anyone else have this problem with the drop I have? Also, I measured the pinion angle and the rearend is pointing up. Does this sound normal with shackles? I would think the rearend would point down. Thanks for any help.

 

How much does the pinion point up? Can you get a picture? I wonder if your center section twisted around the tubes?

 

I measured it and its about 3* up. I havent been able to get the whole truck up on stands to measure the tranny angle. Is there any way to check if the center section has twisted?

 

I would try 4 or 6* shims and see what kind of clearance that gets you. Is your driveshaft incurring any damage when it contacts anything?

 

Its not bent or anything, just light rub marks for now. The sound is like a light ringing. Its a steel drive shaft, not like the crew cab models aluminum tube. I'm going to get the truck up on stands tomorrow and get all the angles measured out, from what I've heard, the rearend should be pointing down about 3* to make up for axle wrap. The driveshaft looks level right now, but I can't get a good reading until I get it off the ground. I'm planning on measuring the bed angle and matching it when I set the truck on stands.

 

That happened to me at 115 and WOT when I had my one piece alumnium DS...not good!

 

Got the truck on stands and measured everything. Rearend is about 3* up, drive shaft is 1* up, and thans output shaft is at 3.5* down. The rubbing is limited to the evap. canister bolt, and the bolt/mount moves when I push on it. The crossmembers don't rub, so I'm not too worried. The marks on the driveshaft are cosmetic, and shouldn't weaken the shaft (steel).

So now I'm not worried about damaging anything, and there's no vibration at all, but I hear that the pinion should be pointing down about 3* to compensate for axle wrap. That means a 6* shim should get me 3* down, and the drive shaft would point up a little more, and the trans would stay the same. I'm going to try this next week, but is there anyone out there who has their pinion angle set to 3* down? If yes, does this help you traction wise or for better performance.

 

I had the problem of the driveshaft hitting the crossmember. That's how my transmission exploded. The drivershaft flung a weight and about 100mph sever vibration occured. By that time it was to late and the u joint came loose at the output shaft. Completely blowing off the tailhousing, output shaft and all. So i'd advise in fixing the problem.