Front and Rear swap suggestions please

[usar17]

Hello everyone. I know there are multiple threads with who prefers what axles already on here. Just looking for a suggestion for my application.

I have a 1985 K10 305v8 with a 700r4. Current axles are both GM Corp 10-Bolt 3.08 gears. Rear is not a posi.

This is a fun restoration truck for me currently. I have a job that requires me to get to work regardless of weather conditions in here PA and Maryland so I need a reliable 4x4. I use to own a 2004 Chevy 1500 with a rear G80 locking differential (i believe that's proper explanation) that got me through just about anything. Love letting off the gas, having the rear lock, and crawling through anything.

So what I'm getting at here is, what axle set up would you recommend for similar performance? I do a lot of driving around town, good snow storms, and mild-moderate off-roading at times. If i don't swap the whole front i am definitely switching to manual locking hubs at least. wouldn't mind rear disc brakes also


Thanks everyone, Lemme know if you need more info

 

[skysurfer]

What's your budget?

 

[usar17]

id like to keep it reasonable. I haven't started looking yet so i have no clue what complete axles cost. Or is it easier/cheaper to convert my current GM10 to a locking rear?

 

[usar17]

i guess what i'm asking is:

Suggested Ratio?
Should I shop yards for different axles or should i rebuild my current GM10s with new locking diffs?

 

[bucket]

What size tires do you have now and do you plan to go larger?

 

[usar17]

guess i should have included future plans.

Currently running 31x10.5R15

I haven't decided on how big i'm going on tires, but i am planning a 4" lift down the road.

There are a lot of big salvage yards in my area to look through and shop around. I would like to drop a 350 in, along with the springs, driveshafts, and axles from a 3/4 ton. Just curious which axles i should look for and gear ratios

 

[crazy4offroad]

Dont buy anything until you've made up your mind on tire size. Re-gearing is too expensive to do more than once. It will also depend a lot on whether or not you plan on keeping the 700R4. With 4" lift you could run 33"-35" tires, maybe 36 if they're advertised 36 but actually measure a little less. Even to re-gear your 10-bolts you're looking at around $350 per axle, plus labor if you have someone do the work for you. Sometimes you can find both front & rear, complete axles, with the gears you're wanting for the price of re-gearing just one. For what you're wanting to do I would think a 14 bolt semi-float rear 6 lug and corporate 10 bolt front with 4.56 gears would be a good choice, for 35" tires and 700R4 trans. But if you ended up wanting to go higher than that and bigger tires all that would change. For rear disk brakes you need to find out if your vehicle inspection requires a park brake to be installed and functional. If so it could end up being rather expensive. There are cheap bracket kits that let you use 1/2 ton rotors and calipers on the rear if you dont require the park brake, and if you do need it you could do Eldorado calipers with the park brake made into them but they dont work very great. You may have to look more into aftermarket and that = more $$$.

 

[usar17]

im definitely not going bigger then a 35" tire. I'm not looking to build a monster here. Just a nice sized all around truck. I'm keeping the 700r4 bc there is nothing wrong with it and shifts like a dream.

I'm pretty set on looking through the yards for a good 3/4 ton square body. Just was curious which axles to try and find if i have options: DANA 44, 60, or GM14. In a perfect lucky world (lol) what would be a good find?

 

[crazy4offroad]

A Dana 60 for under $500 would be like finding gold in your back yard. They usually sell for $1000-$1500. Not much difference between Dana 44 and Corporate 10-bolt fronts. If you want 8-lug the outer hub assemblies of D44 & 10-bolt interchange I believe. 14-bolt semi-float or even a 12 bolt would probably be fine for what you're wanting if you're not pulling a trailer. A 14-bolt full floater would be good for hauling, find one for a 3/4 ton and the leaf spring pads will be the same width center pin to center pin as your 1/2 ton axle. You may have to have your driveshaft lengthened to finish the swap though unless your truck is longbed. By the way I wouldnt take anyone's word for it when they tell you the ratio. Pull the cover and count the ring & pinion's teeth and divide the numbers together. 41 ring gear/10 pinion=4.10 ratio or same as 4.11 ratio. And if you end up with some off number count again just to be sure.

 

[usar17]

So shop around for a 44 or 10 front and a 14 or 12 rear. With a high ratios

 

[crazy4offroad]

For 35" tires 4.56 gears would be great but I think you're more than likely going to find an abundance of 4.11 ratio axles.

 

[usar17]

Anything wrong with that? Axles aren't my specialty. I don't know how the ratio helps or hinders things. Or what the differences are between semi floating and floating. Ill have to do some Google research tomorrow

 

[crazy4offroad]

4.11s would make lower rpms than 4.56 and you kind of have to find the sweet spot. With a 700R4 if the rpms are too low you're putting strain on the trans and will shorten its life.

Difference between floating and semi floating is the wheel bearing style. Semi floating is just like your 10 bolt or a 12 bolt, the axleshaft passes through the bearing and the weight of the back of the truck is actually riding on the axleshaft's bearing flange. Full floating has outer hubs that have wheel bearings to connect the hub to the axle tube. The axleshaft has no weight on it at all, so when the pinion starts spinning, the axleshaft drives the wheel hubs with no drag of weight on the axleshaft. Only thing riding on the axleshaft is an oil seal.

 

[crazy4offroad]

Your truck with a 700R4 trans, NP208 t-case, 35" tires and 4.56 gears would be doing about 65 MPH at 2,000 rpms which is pretty good. At 2,500 rpms you would be doing about 82 MPH. 2,145 rpms would be right at 70 MPH.

http://www.grimmjeeper.com/gears.html

 

[usar17]

ok thanks. I always figured lower highway RPMs were better. thanks for the eye opening