Good morning everyone,

My Excursion has a 5" Superlift 35" tires. Runs and drives great. The front is a full spring lift, the rear is a 5" block. No vibrations or apparent issues.
Put the truck in reverse last night and had to step on the gas fast and hard and bang, the rear driveshaft dropped. The slip joint separated and torn the boot. It appears that there is no other damage. My guess is when I torgued it hard in reverse the pinion dropped, the rear tires flexed the axles backwards and it was just enough to disengage the slipjoint splines.
Anyone hear of this or have this happen? I'm figuring the driveshaft probably needs to be lengthened an 1", maybe 2" but want some input.
This truck is a pavement queen and family hauler. I'm happy with the suspension set up as it rides really nice, I don't want to swap in stiffer springs.

Any suggestions?

Thanks

 

I've done some looking and I'm wondering if it isn't my Driveshaft but rather my rear leaf springs being worn out and too soft, then add the leverage that the axle with 5" blocks have and BAM!!! No wonder it separated.

 

With that lift, the rear shaft prob should be lengthened. The lift block does let the axle "walk" around under there a bit. A traction bar would help, or get lift springs to replace the blocks.

 

I've got five inches of all spring lift and have never had this issue. You may be correct about the springs and block...