What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

pro/con of 3/4 or 1 ton axle swap

I ran a d44/12b combo and 36s for a number of years with no problems... You have to be totally aware that you can't get all bound up and throttle the piss out of it...

Make sure you carry spare shafts and the tools needed to change them on the trail...

If you do upgrade, find a 3/4 ton 14bff with better gears and throw on 8 lug junk in front...

You may be able to find gears for the 10b cheap enough, or just grab the 3/4 ton front out of the same rig you jack the 14b from... If you find a good deal on a whole truck you can pull the 56s, axles, and what ever else you may need and part the rest out...
 
6.2Blazer said:
I don't know how you drive, but would probably say a D60 front and doubler is pretty overkill for a rig on 33's and possibly 35's in the future.
Click to expand...

I've been going over a lot of rocks, not boulders, just really rocky terrian. 4LL has been too fast at times. I'm looking into the doubler to reduce my speed. And looking ahead at going with larger tires and if I really need to upgrade the axles to 3/4-1 ton because of the larger tires.

6.2Blazer said:
For gears, you said you had an 205 and if an automatic (TH350 or 400) then the crawl ratio is pretty crappy.
Click to expand...

I haven't clocked the gears, I'm only assuming that I have 3.73s because that's what's in my '77. Both have SM465.
 
And just today I've come across frt and rear axles off a '76...$250 for both. Look in ok shape.
 
nah, that came factory. i seen one at the junkyard in a 74 k20, but it was too damn hot to pull it.
 
ramack said:
Why not put 4.10s in the GM 12 Bolt?
Click to expand...

Well, my truck had 2.76's from the general so I needed to replace the front axle too. As it turns out, a friend had both axles with the frame for $100. I couldnt get the cash out fast enough. I lucked out and saved the spring hangers just in case. they like to rust out bad up here.
 
I didn't read every post....

If he wants a doubler, 4.88+ gears, front and rear lockers, crawls on rocks, and has a 4spd, he's gonna need a 60 front. Doesn't matter what size tire. With that much gear reduction, a 10b/d44 shaft will snap like a pencil.

60's aren't over rated, not even close. Why would you even say that? :rolleyes::haha:

10b's and d44's are over rated. Waaaaaay over rated.
 
60's rule just hold a 60 shaft in one hand and a 44 in the other. Its a no brainer if you are worried about breaking something onthe trail. plus its a full floater so if you dobreak an axle the wheel doesnt fall off. Plus i wheeled the crap out of a 12 bolt and this is what i got. broken the tubes free and broke and axle and had the tire fall off. Only down side to a 60 is its 550 pounds and it a swift kick to the groin money wise unless you get lucky
 
This evening I jacked up the front, spun the drive shaft. What I measured was 2.82:1. Man no wonder this thing is a dog...I'm going to measure it again tomorrow morning to double check. Granted I was doing it in the dark with just a mini-mag, but I don't think I can be off by much.

Whyyyyy would it be geared like this???? I saw 79rustyK10 had 2.76's, so I guess what I'm seeing on my '79K5 is possible.
 
Ive never heard of gears lower than 3.08's in a 4x4... until I got this last K10. pretty odd thats for sure, but with a strong engine and a tailwind, 130 mph might be possible lol.

fuel economy is the reason most got high gears like that from what I understand. seems a 3.50 or so gear would get better overall mileage than those though. almost unbearable in town or stop and go traffic. Im really bad about my leadfoot though too.
 
The 3/4 ton axles with 4.10s that I have come across are looking better and better.

I'm assuming that the 14BFF rear end has similar ground clearance issues that the D60 has?

Nevermind, I found the tech article about the 14BFF.....
 
Right now I have 33x12.5. I bought used ones that I hope will last long enough that I can get my ducks in a row. With the current axles, I was planning on going with 33x10.0s. If I go with larger diameter tires, I'm going to need a lift.

From what has been suggested and what I've read, with 14 bolt and 35's I'm going to have less ground clearance than what I have now with the GM 12 bolt and 33's.
 
I wouldnt really worry about it. if you want you could always grind the bottom lip off the 14 bolt.

If ground clearance is a really big deal you could have the 12 bolt re geared or swap in a SF 14 bolt. the 12 bolt pretty much the same strengthwise as a ten bolt.

really... budget is the only limiting factor. With 33's you can probably get along just fine for a long time if you drive nice with a 10 or 12 bolt rear.
 
Yes, front axles are considered a full float design.

From what has been suggested and what I've read, with 14 bolt and 35's I'm going to have less ground clearance than what I have now with the GM 12 bolt and 33's.
Click to expand...

Keep in mind that most 3/4 ton axles are the 14 bolt semi floater rear which is marginally larger in housing size than the 12 bolt, hardly losing much ground clearance. The internal parts and axle shafts are a huge difference compared to the 12b.

But on the off hand you find a 14 bolt full floater, that axle housing is where you will lose good ground clearance cause of it's size. If you are staying 35" tires and under, this axle is not needed for your application. Wouldn't hurt to have but not needed. Plus you may pay more for a 14bFF if the seller knows what they have.
 
I've cut and pasted text from the "Axle Identification Chart"
http://coloradok5.com/axleguide.shtml
The first GM 14B is the 14BSF and the latter is the 14BFF, correct?

GM CORPORATE 14-BOLT
The "small" GM 14-bolt has a 9 1/2-inch ring gear diameter. It was used in the rear of 1964-and-later GM pickups, and in the rear of 1984-91 3/4-ton Suburbans.

GM CORPORATE 14-BOLT
With a 10 1/2-inch-diameter ring gear, the biggest 14-bolt GM rearend looks much like a Dana 70, and is but a few thousandths of an inch shorter in ring gear diameter. This axle is commonly used with big engines and/or overly large tires. It was used under 1973-87 3/4-tons.
 
You must log in or register to reply here.

Latest Posts

Top Bottom