1 ton duelly rear end swap

[oldiron]

The pinion bearings are going out on my 1 ton flat bed. The local shops want $850..00 to put in all new bearings and another $250.00 for a new ring and pinion gear set changing the ratio from 5.13 to a 3.73.
The choice I have is rebuild the present rear end or go with a later model rear end from a 73 to 82 dually.
Has anyone done this and what modifications did have to do?
Thanks for any help.

[kwmech]

Pulled the rockwell out of my 69 and converted over to a dana 70hd, spring perches were in the correct place, had to move the shock mounts and replace the intermediate e-brake cable with a longer one, had to redo the 2nd half of the driveline also. Really not to bad considering going from a 69 axle to an 84. OOOPS major thing--had to use the later rims because the rockwell wheel studs are 1/2 and the dana 70 were 9/16 but I wanted to get rid of the split rims anyways. Not sure if you can get away with drilling them out or not I never checked on the rim centers.

[oldiron]

Thats OK I have a set of later model rims. The ujoints the same? And how much did you have to shorten the driveline?
Thanks for the info.

[oldiron]

ttt

[BigBlockBurris]

OldIron,

Hey pal, you know there are two different "dually" rear ends. The rear end that came in a dually truck (with a bed) is a dana 70. Around here they are difficult to find and very $$$ when you do. The other rear end is still a dual tire rear end but came mostly in cab and chassis trucks, like the one in your avatar. A buddy of mine has a factory cab and chassis flatbed, 69, and it had a eaton rear, but it was cab and chassis width. Cab and chassis came with a coporate 14 bolt but it is still dual rear tires. Make since or did I confuse you more? When we put the corporate in the 69 we changed drive shaft length, U-joint, and shock mounts. Everything else bolted up. Now that I think about it, every 67-72 one ton truck I have seen has been a cab and chassis width rear end. I don't know if they made a full (dana 70) width rear end back then. It would be intersting to find out. Let me know if you have any more ???'s.

BBB

[zyggy72]

Go with a later model rear end, it is easier and cheaper on parts. Right now I'm just starting the conversion from dana 60 leaf prung rear to an 82' dana 70 dually rear in my 72 chevy.

[oldiron]

Guys, thanks for the info. I understand the differance between the late model dually bed and cab&chassis models with the pickup style being wider. Since I have a 8 ft wide flatbed I thought that the wider axle would be a little more stable.
Do the spring pads match up on the later models with the 67 - 72 models?

[zyggy72]

With the pickup style wider rear end you may have to move the pring pads in some. I know that that is something I will have to do during my swap.