Axle Choice

[blazing816]

Hey all, I have a 87 K10 that has 3.08 gears, I want to put 3.73 in there with my 700r4. Mostly doing little hauling, but do tow a 4000lbs camper here and there. Anyways I was wondering what option you guys thought was better:

1. Keep the 1/2ton axles and buy new ring and spline gear to make them 3.73. I do not remember what axels are on it but its the base base model, have to look when I get home.

2. Or I have a chance to get k20 3/4ton axles that are already 3.73 and its a cooperate 10 bolt front and I believe cooperate 14 bolt rear because it is off a 85 did not think they used cooperate 12 in rear then (hard to count bolts on the picture).

Anyways I was curious if the cooperate 10 and 14 will be much stronger and nicer then the 1/2tons?? because I can get the 3/4ton fully from brake to brake for $200 or possibly less.

Thanks in advance for your input.

[joesig]

I would go the 14 bolt route if it is the full float type. The cover resembles a stop sign.  The semi float 14 bolt looks more round.

3.73 gears alone will be $200 used plus the install kits will add up.

[Jason S]

The 85 K20 axles should be Corporate 10 bolt front and Corporate 14 bolt rear.  It is very possible the 14 bolt is the semi-float version which is generally a good axle.  The front is the same version as currently under your truck, except with 8-bolt wheels.

I think for $200, the K20 axles sound like a good deal.  I would inspect the axles and check to see if bearings and pinions are tight and ring gears have a good pattern.  Even if the bearings are on the loose side, the cost for bearings and seals would be less than two new gear sets, bearings and seals for your existing axles.  You will have to swap on 8-bolt wheels and maybe other parts, depending upon braking options with the new axles.

[Irish_Alley]

http://coloradok5.com/axleguide.shtml

[blazing816]

Thanks...that is what I was thinking, the only part was I had some chrome 6-lugs I was going to use, but I can always get different rims. Here's a pic of the rear end, do you guys think is semi or full float?? and what does that really do??



Pic of the front axle:

[Jason S]

The rear axle looks like a full float 14-bolt.  The full-floating axle is a very good heavy duty axle. 

Full float axles have a spindle on the end of the axle housing and have the large hub sticking out past the wheel. The axleshaft's only job is turn the wheel, it does not carry any weight.

Semi float axles are what most 1/2 ton trucks and rear-drive cars from at least the mid-50's to present have used. In addition to the axleshaft driving the wheels, the axleshaft also has to carry the weight of the vehicle. 

[Irish_Alley]

so if you brake your axle shaft the wheel can fall off the sf, a ff wont and can carry more weight. the front is a 10 bolt. its thought to be weak but me and my buddy run a (my truck) dana 44 and turning 38"-40" tires and (his truck) 10 bolt turning  44" tires. now we both have pretty much stock motors so no major hp but i have broken a couple axle shafts and knock on wood hasnt broke anything. one thing to do is MAKE SURE YOUR RATIOS ARE THE SAME. the best way is to pop the cover off and do the math