The Stovebolt Site Forums The Parking Lot Big Bolts 42 chevy 11/2 ton rear end swap

im wanting to pull the factory 2speed rear out of my 42 ton and a half...im wanting to replace it with a later model 1 ton chevy rear ...anyone done this ????i know that ive got a rear out of a 84 cab&chassis and they are a little shorter than a dually rear the rear i have is about 2inchs to short....

This is a pretty simple swap, are you gonna get rid of the dually rear wheels?

Later dually rears are pretty close in width.

Be careful to keep yourself in a useful power band if you're gonna use the truck for work at all.

the truck has new small block and 400turbo trans...yes im gonna use dual wheels it going soon to get a custom car hauler bed put on

If you're going to make a car hauler why are you lowering the carrying capacity. Why not leave it as a 1-1/2 ton truck? If you want higher speeds add a overdrive unit or put a 2-speed rear in. My 2-1/2 ton wrecker with a 350 SBC, SM420 trans and a 2-speed rear will run 70+ mph. My fire truck will run in the low 60's after I swaped in a 2-speed rear...before the swap it would max out at 53 mph. I paid $250 for the fire truck 2-speed rear set-up.

Mike B

mike the truck already has a 2 speed rear in it ...im just wanting to bolt in a later model 1 ton rear out of 80s-90s chevy 1 ton

I know an overdrive system will help with higher speeds but a 2 speed rear should not, it only makes it easyer to pull a heavy load from low speed, right? I know this from my 1.5 ton truck. The orriginal owner put in a two speed thinking it would make him go faster up top but the truck still maxes out at 45-50 mph. It will haul a house though

"ur2 slo" is correct, Most 2 speed rear ends will only change your top end speed by 4-5 MPH
if evan that on my 46 I looked in to a 2spd rear end and it only changed my final drive ratio a vary small amount

2 speeds work best for split shifting on a hill with a load

Like any single speed rear, the 2-speed rears are available with many different gear ratios. You need to do your homework first, the past owner might have installed a rear that has a lower ratio.

My experience with 2-speed rears on these old trucks is that the second speed is deeper than the standard rear and intended for getting a heavy load moving. I've never seen one era correct that would allow you to go faster than your current high.

Something you might look at is one guy swapped the ends of the axle housing to the newer axle and then redrilled the hubs so the newer axle shafts which bolt up, allowing running the original brakes and wheels while having a later axle ratio. Do some searching and you should be able to find that thread here on the Stovebolt.