Rear axel swap

[Nak]

don't even think about it. one day you are going to forget something and WHAMO!. Instant drivetrain damage.

What he said!

 

[Symba_The_Lyon]

Hey there guys i just got my self a sf 14 bolt finally, They guy's at the junk yard opened the diff case and got the number off the ring gear and did the math and they stayed its the right ratio witch is 342, Now how do you find out the ratio when you open the case with the number on the ring gear i am just wanting to double check before i do the swap? @Nak when you did the swap did the drums make you're tire in the back stick out farther because of the drum sticking out so far??

 

[Nak]

For the ratio, count the teeth. Gear ratio is ring teeth divided by pinion teeth. The axle width, wheel mating surface to wheel mating surface should be identical between the 10 and the 14SF. My rear wheels stick out exactly the same as they did before.

 

[2wdr]

OK, I have read and reread this several times. I am looking to replace the rear end in my 1999 2wd 2dr with a 14 bolt. I understand to look for the brake size code JB6. And I need a GU6 3.42. But here is where I get lost a bit. I do not want the G80, soooo, what code do I need to look for?

G91 would be nice for me, but , is that still a Posi limited slip too?

I hope to find one in the vehicle and not have to open 12 to find one.

 

[livingez_123]

If the rear is bouncing, have you thought of better shocks to control the axle movement?
Have you also thought of using an NBS 3/4 ton axle and just changing the bolt pattern? the little stuff like spring mounts can be easily changed.

 

[Nak]

OK, I have read and reread this several times. I am looking to replace the rear end in my 1999 2wd 2dr with a 14 bolt. I understand to look for the brake size code JB6. And I need a GU6 3.42. But here is where I get lost a bit. I do not want the G80, soooo, what code do I need to look for?

G91 would be nice for me, but , is that still a Posi limited slip too?

I hope to find one in the vehicle and not have to open 12 to find one.

G91 denotes a 6.83 axle ratio according to the lookup I did?

JB6 is a good start, but I have seen some 10 bolt rear ends with the JB6 brakes lately... C5Z denotes 7200 GVWR, and that should definitely be a 14 bolt Semi floater. Y06 and Y07 both denote 9.5" ring gear, but I've seen 14 bolt SF rear ends in vehicles that did not have those RPOs listed. To avoid G80 just find a rig without it listed on the RPO sheet. However, it's always possible that someone could have swapped in a G80 unit at some point so it's important to pull the cover before buying. Also, measure the distance from outer brake drum to outer brake drum to verify. The 2WD and 4WD rear ends are about 4" different in width.

 

[jerryjoe28]

ok guys sorry to bring a old thread back to life. I just found a 94 1500 with a 14 bolt and 6lug. after reading this it sounds like it should be just a pretty straight forward swap?...... my question is what do you guys think about rear disk conversion kits? and any reccomendations on where to get one?

 

[Nak]

Yep, pretty easy swap. Just need a conversion rear U-joint; everything else bolts right up. Rear disc would be great for sure, but you might want to try the 11" rear drums that come on the 14 bolt first. It's a pretty big brake upgrade over what you have now. Fortunately, the proper combination valve is still available new. At first glance, it looks like it's part of your ABS unit, but it is separate and bolts directly to the ABS unit.

Anyways, I'd see how happy you are with the big drums first, you can always convert to drums later. My plan was to do the disc brakes as well, but the big rear drums improved brake feel and performance so much that I'm completely happy with them. Don't skip the new combination valve though, the 11" drums will put your rig's brakes dangerously out of balance without it.