10 bolt swap to 14 bolt (6 lug)

[Jared Jackson]

Hey Guys,

Not beating a dead horse here, just throwing out for some discussion.

I have a 97 k1500 ECSB. It currently has a 10 bolt, open diff with 3.42's. I, of course, want to find and upgrade to a 14 bolt (6 lug) for added strength and to support future mods. I spent a few hours scouring the internet to find and compile information to assist me with finding the right axle. Unfortunately, information is sometimes inconsistent when dealing with forums. What I did put together, however, is that the 14 bolt axle (6 lug) from the 2wd 2500 trucks in our year ranges were shorter from wheel mount surface to wheel mount surface. The 14 bolts that came in the 1500 trucks stock are longer from end to end...

I found a 14 bolt out of a 89 2wd truck with 6 lugs. The thing is, I am nervous about picking it up (even though it is "cheap" $250). I know I could possible make it work with offset wheels or even spacers (don't really want to do that). But, I have no plans for offset wheels. I actually have my eyes on a set of 6 lug deep dish GM rally wheels!

I have called every pick and pull, auto salvage, and 4wd shop in my area. 95 percent of the time, the guy that picks up the phone has absolutely no idea what I am talking about (in Texas, we even have language barrier issues sometimes).

Me: "I am looking for a 14 bolt rear end."
Them: "Ford?"
Me: "No, 14 bolt, I am swapping a 10 bolt out of a Chevy."
Them: "2010?"
Me: "No!"
Me: "Do you have any 88-98 k1500's with 14 bolt axles?"
Them: "Yes, we have that truck"
Me: "With a 14 bolt axle? It's kind of rare! Do you have that specific axle??"
Them: "We have Ford and Cheby Axles"
Me: "OK, thanks!"

Some are rude and just tell me to "come look." I get that, you don't know if it has that specific axle. But you are there, I am 100 miles away and you can go out there and count a few bolts for me to possibly make some money. I don't really want to drive 100 miles to find out you don't have what I need. It's all good though, I am not sweating that.

I ranted...

Has anyone reading this successfully swapped the 2wd 2500 6 lug axle into a k1500 that had a 10 bolt? If so, did you have any issues?

Anyone else have thoughts?

 

[df2x4]

If you're putting it into a 4wd truck, personally I'd stick to buying a 4wd 14 bolt to avoid the length differences you mentioned.

Have you checked http://www.car-part.com? They have an inventory of parts for a ton of salvage yards nation wide. Would at least save you some annoying phone calls.

 

[slowburb]

The axle you need is out of a 4WD 2500 truck that is considered a "light duty" 2500. This is the designation for the 6 lug hubs (and 9.5" ring gear), instead of the 8 lug hubs (and 10.5" ring gear) found on a 14 bolt full floater. The 2500's were built with both combinations. All 2WD trucks have a narrower axle width. For a straightforward swap, you want a 4WD axle. Also, the 1500 diesel 4WD suburbans had the 6 lug/9.5" semi floater 14 bolt.

If you call junkyards, ask if they have any 2500 trucks with 6 lug hubs. That's the easiest way.


You're also going to need to find one with GU6 (3.42:1) gears inside it (unless you're ready to swap the rear gears in the new uinit to match your fronts, or front gears to match the rear you buy). I'm not sure how easy it will be to find a 3.42 9.5" 14 bolt. It doesn't seem to me that many heavier duty trucks would be set up with that high of a gear ratio.

 

[Jared Jackson]

If you're putting it into a 4wd truck, personally I'd stick to buying a 4wd 14 bolt to avoid the length differences you mentioned.

Have you checked http://www.car-part.com? They have an inventory of parts for a ton of salvage yards nation wide. Would at least save you some annoying phone calls.

I have not! I am going to check it now! I have stuck to, for the most part, craigslist and FaceBook marketplace up until now. (except for calling local and regional salvage yards)

My thoughts on the 4wd as well... just wanted to know if I was passing up a good deal or not on the 2wd axle.

 

[Jared Jackson]

The axle you need is out of a 4WD 2500 truck that is considered a "light duty" 2500. This is the designation for the 6 lug hubs (and 9.5" ring gear), instead of the 8 lug hubs (and 10.5" ring gear) found on a 14 bolt full floater. The 2500's were built with both combinations. All 2WD trucks have a narrower axle width. For a straightforward swap, you want a 4WD axle. Also, the 1500 diesel 4WD suburbans had the 6 lug/9.5" semi floater 14 bolt.

If you call junkyards, ask if they have any 2500 trucks with 6 lug hubs. That's the easiest way.


You're also going to need to find one with GU6 (3.42:1) gears inside it (unless you're ready to swap the rear gears in the new uinit to match your fronts, or front gears to match the rear you buy). I'm not sure how easy it will be to find a 3.42 9.5" 14 bolt. It doesn't seem to me that many heavier duty trucks would be set up with that high of a gear ratio.

Up until your post, I had no idea the 4wd 2500 trucks even came with 6 lug axles. I don't think I ever came across that info during my research.

I have complete plans to re-gear the axle before I install it (and re-gear the front diff as well, of course). My plan is to go to 33's, so I was thinking 4.10's.

I am going to check the site that was posted by df2x4 and then call a few more yards and ask for 6 lug 2500's. That does seem easier than them trying to figure out how many bolts are on the cover.

 

[Jared Jackson]

I actually found one out of a 94, 1500, 4x4, with 3.42 gears and a g80 posi. That might be worth picking up because I can ride around on it while I prep to re-gear and build my rear end...

that website is pretty sweet, I am surprised I have not ever visited it yet!

I just hope that axle is still available when I have time to make an 800 mile round trip to West Texas! They close on the weekends :-(

 

[slowburb]

I actually found one out of a 94, 1500, 4x4, with 3.42 gears and a g80 posi. That might be worth picking up because I can ride around on it while I prep to re-gear and build my rear end...

that website is pretty sweet, I am surprised I have not ever visited it yet!

I just hope that axle is still available when I have time to make an 800 mile round trip to West Texas! They close on the weekends :-(

I'd want to make sure it was a 14 bolt before making that drive, bro.

 

[df2x4]

I'd want to make sure it was a 14 bolt before making that drive, bro.

If he found it via the car-part.com lookup, it should be. You select which axle and gear ratio you're looking for and it brings up exact matches. But yeah, I'd definitely make a phone call before a road trip that long.

EDIT - If it's the fact that it's out of a 1500 that is concerning, I'm pretty sure some of the K1500 diesels got the 14 bolt six lug semi-floaters. Possibly other K1500s as well.

 

[Jared Jackson]

Sorry, I did select 14-bolt and that is what came up. I would definitely give them a call before making that drive! lol

There is an RPO code for a "heavy duty" suspension that gives 1500's the 6 lug, 14-bolt rear ends, and I can't find it on Google at the moment...

 

[deadbeat]

F44 is the RPO code.