1/2 to 14ff rear...

[bbchevy]

My 35" tires keep eating my 10 bolt alive. Im able to buy a 44hd front and a 14ff rear for $250. i have heard that in order to put a 1 ton rear in a 1/2 ton truck you have to move the spring perches... yet if you find a 3/4 14ff you dont have to. how can i tell whether its a 3/4 or a 1 ton before i buy it. and if it is a 1 ton, what is involved in moving the perches.

Also, the drive shaft is going to have to be changed to a 1 ton or 3/4 ton also, right?

Other than that stuff... am i going to need to get anything else? Brake lines? Spring plates? I want to get everything i need before i install it.

Thanks,
-Scott

[Prerunner1982]

might check out the 4x4 section on this site as well... and i maybe wrong here... as i often am... but i believe the 3/4ton 14bolt, is a semi floater instead of a full floater 1ton.... not sure about driveshafts, maybe only have to change ujoints...

[EricS76]

I'm in the process of putting a 14 bolt 10.5 in gear in my c-10. Here's what I've found. My 14 bolt came out of a 82 C-30 single rear wheel truck. The spring perches are narrower than my C-10's. It's not hard to change the perches. Just note what angle the stock ones are, cut them off, and weld on some new ones in the right place. If you don't have the tools for this, a welding shop should be able to do it cheap. Go slow and don't overheat the axle tubes. I'm going to use the driveshaft that came off the C-30. The U-joints are much bigger on for the 14 bolt. A u-joint exists that will adapt two different size joints, but I don't know if it'll work for this. I'd rather do it right anyway. The parking break hooks up fine, and I think the brake line will too, haven't gotten that far. As for U-bolts and spring plates, you should be ok if you go with the 3/4 ton axle i'm told. My axle is a one ton, and it uses square u-bolts mounted threads down, so I'm having to go with new u-bolts and spring plates.

The heavier GVWR 3/4 ton trucks should have the 10.5 inch 14 bolt. Easy way to tell is the 10.5 has a hub sticking through the rim when mounted on the axle, and the 9.5 inch 14 bolt doesn't, it's like a 1/2 ton axle.

[Russell]

1 ton trucks have different frames than 1/2 and 3/4 ton trucks. Becuase of this, the spring perches on a 1 ton are located in a different spot than the 1/2 ton and 3/4 ton perches are.

3/4 ton and 1 ton 14 bolts are the same thing, both are 10.5" ring geared full floating diffs. Only difference is in the spring perch locations.

If those diffs are a matched set, and the front is a D44, then it'll be a 3/4 ton rear diff. The 1 ton trucks got D60s (not sure when their production run started, sorry)

To find out for sure, just whip out the measuring tape, measure from centering pin to centering pin on your current 10 bolt, then check to see if it is similar to the 14 bolt's. A little bit of sideways variation is normal, you can move the leaf springs side to side a bit.

[stan79chevy]

youll need a conversion u joint. your driveshaft will still have the half ton yoke and your new rearend will have the bigger u-joint size. the one your gonna have to buy is half ton on one side and 3/4 on the other. they sell them at napa for about 25 bucks.

stan

[Russell]

Actually, he'll need a new rear shaft. The pinion is a lot closer to the t-case than a 10 bolt's is. 10 bolt shaft will be too long.