Making an '87 2500 2wd into a 4x4?

02 2500avalanche · December 25, 2003

Okay here is the deal. My dad just bought a 1987 gmc 2500 2wd long bed auto (turbo 400 right?) 350. The truck is as straight as an arrow. I can not believe the shape of this thing with 190k on it. It has some minimal rust spots and with some nice body work and paint and other minor things the truck would be mint. The only bummer is that it is 2wd and up here in New England the truck is useless. So my question is can I find another 2500 4x4 and hi jack the axel, knuckles, T-case, and other parts and swap them onto the '87? Are the mounts on the frame there? not exactly the mounts but the mounting holes in the frame? This is my dads beater until his '04 3500 SRW D/A comes in so after that I can do what ever I want to it. My future plans would be to build a stump pulling 454 torque monster with a nice 5 speed truck tranny to slam gears in, mabey a Dana 60 up front with a full floating 14 bolt out back, nice 10 or 12" lift with some 38's, paint it forest green and top it off with a 4" cowl hood. Boy I love to dream

Alex

Colorado Kid · December 29, 2003

I don't know about the C-2500 for sure, but for the half tons the answer was no . . . the frames and cab floors were different.

I'm pretty sure the story is the same for the C/K-2500 because (like the 1/2 ton) the C-2500 used a coil sprung short and long arm independent front suspension while the K-2500 had a leaf sprung "solid" front axle. The paths for bringing loads from the wheels to the chassis are so different I doubt that the same frame was used for both applications.

boflaade · January 18, 2004

At one time mankind did not have 4 wheel drive. Some of those went out and put in a Detroit-Locker and were able to drive down those lonely roads. Others stuggled on and still made it home. Surely a few in your neighbour hood have useless 2 wheel drives. Ride with one of the many that have 4X4s.

It would be cheaper to buy a 4X4 then make one out of one that don't unless you have an unlimited source of income.

Engineer · January 27, 2004

Been here, done this.. over, and over....

The eaisiest solution is to find an old, mechanically sound 4x4.

Basically you are taking the body off the 2wd, and replacing the 4x4s sheet metal. The 4x4s entire frame will need to be used. Any year frame from '73 to '87 will work, but the newer the better. The rubber bushings the cab sets on, should be the same year as the cab, not the frame.

Choose wether you want a 4sp. or an auto. 1/2ton, or 3/4ton, 1-ton. And buy accordingly. The 1-tons have a heavier frame than the 1/2, or 3/4 tons. As well as the heavier front axle. The '81 and later frame is cut different where the front bumper mounts. Not a big deal, but something to consider.

If you want the 4sp, you will need to rob the clutch linkage from the donor truck. The floor boards are different in the 2wd cab so a section of the "dog house" from the 4x4 will be needed to clear the transfer case. As well as steering columns will be different for a 4sp.

It is not a huge under taking, but this is something that can't be done in a weekend either. Just be thankful that the General made so many parts interchangable over the years this truck was built.

If your '87 350 truck is fuel injected, you will need the '87's fuel tanks on the new truck. As well as the '87's fuel injection system, unless you will be building the 454 you mentioned with a carb setup.