05-07 3/4 rear swap

[K5 Silverado]

I keep hearing to swap out my 10 bolt with 3/4 running gear from th 80s truck. I searched the forums and didnt find out if the new 3/4 rear would work with my 87 blazer. I though about the new 05 - 07 because they already have disc on the back. would they be a direct fit too ? and what would the chances be of them having 3:73 gears to match the front, then I would just put the 8 lug conversion adapters on the front.

 

[uao85]

I have thought about this too. still has me curious. Anybody??? I have been wondering about this to get a factory proven rear disc/parking brake setup that was designed to work on a fullsize gm truck without having to coble together a bunch of parts and without having to pay an arm and a leg for a kit.

Remington

 

[onetonbb74]

cut and weld new shock tabs and spring perches with new ubolts and spring plates. Fab ebrake cable mounts, and resize your driveline get a new u-joint. Fab new rear brakelines to work with your current brake line setup.

3.73's are common.

I don't think there is a true locker for the newer AAM axles yet, could be wrong though.

 

[Desert Yeti]

If you're handy with a welder and have one of these axles already laying around, seems like a worthwhile project! Otherwise, it's hard to beat a 14b FF for ease of installation and how cheap they are to buy, even if you have to cobble together a disc brake setup.

Got me thinking though...how do the new 3/4 or 1 ton AAM axles compare with the "old-school" 14b FF's for strength and (even more interestingly) ground clearance? Anyone know?

 

[uao85]

Thats what I am thinking. To me, even from just straight appearance, the covers look the same and to be identical between the 14 bolt and 10.5" new gm 14 bolt. I am wondering if I can just swap out carriers with gears and detroit from my cucv rearend into a new disc equiped axle???hmm

Remington

 

[throttleissues]

I decided to go measure my 05 2500HD after reading this thread. Rear spring pads are 49" on center, shock mounts look like they would work(although slightly lower), and the brake lines look like they would fit easily. Single brake line comes down to axle and two side lines thread in, same as most. The big problem looks like ground clearance. It looks like the same clearance as my 14ff, but I don't think you could shave the bottom of the newer axle. It has a drain plug at the bottom, and I think shaving would break into cavity.

 

[uao85]

What about axle tube diameter??? Maybe if the tube ends could be swapped or one chopped and grafted to the old school 14 bolt you could have a factory disc brake rear on an old school axle...just thinking out loud here.

Remington

 

[throttleissues]

I didn't think about that. I can measure that tomorrow and look at mounting brackets. Makes me wonder if the hubs would be interchangeable.

 

[throttleissues]

I did a quick comparison of axle tube OD with a string , and they appear to be the same. The caliper brackets just bolt to a flat flange that is welded to the tube. That bracket would be easy to fab if the hubs/rotors would fit, but I'm not taking 2 of my trucks apart just to find out.

 

[uao85]

two words..........common................just call it curiousity...jk I dont blame you...maybe I can find a scrapped axle out of a wrecked truck one of these days.

Remington