2wd frame?

[TerryD]

How does a 2wd frame compare to a 4wd frame? My 4wd frame has turned out to be rather rough around the spring mounts, enough so that I don't think it's worth fixing. I do have a good 2wd, but I've noticed there are some differences in width of the frame c's around the steering box area and an interesting hump in the frame dipping down behind the cab.

I've had to take a break from the truck. I worked swing shift for a few weeks and that stopped my progress, then the guy who's shop I'm using started building a trailer that he's not had time to finish. The job he's doing right now is close to over and then he'll be getting his trailer done so we can get out trucks in there and work on them.

 

[tRustyK5]

A frame is not a frame is not a frame...

They appear to be similar, but do vary quite a bit. 1/2 ton and 3/4 ton are visually similar, yet the 3/4 ton is thicker. Step up to one ton and the center of the frame is 8" deep instead of 6" and it's thicker yet.

Minor differences between 2WD and 4WD, so I've heard. I'll find out first hand with my Crew Cab which is a 2WD one ton that's going to be a 4WD one ton.

K5 frames are the smallest and thinnest...

Rene

 

[TerryD]

4wd: 79 K15 Sierra Grande long bed

2wd: 76 C15 Sierra long bed

 

[tRustyK5]

No strength differences between the two, but you'll likely find the trivial differences between the 2WD and 4WD like I will. Howdiy has done the 2WD to 4WD conversion and should be able to pinpoint what the exact differences are.

Rene

 

[cybrfire]

First crossmember behind the front bumper is different. Doesn't really matter unless you want to go to the work to swap it over.

Engine crossmember is different. 2wd has alot of coil spring bucket stuff attached to it and in my experience it all must be removed and 4wd counterparts put in its place.

Your 2wd frame may need a set of holes drilled for the trans/tcase crossmember.

You will need to drill some holes for your front front leaf spring hangers. Rear of the front leaf springs you'll need to drill and mount the eye hanger up inside the frame rail. 4 3/8" holes and a bigger one. Can't remember the size. Good chance you'll also have to clearance for the shackle to swing without rubbing the frame.

Your rear spring front hangers will have to move from one to the other. 2wd's are shorter or higher which makes the rig lower to the ground.

That's all I can think of off the top of my head.

 

[TerryD]

I've noticed most of that. I was mainly asking about the rails themselves, sorry I was so vague.

The plan is to build a new engine cross member, custom spring hangers for the front, and I'm undecided on the rear. My 4wd spring hangers on the rear are rotten. We managed to "tear" the springs off the front rear hangers. I'm considering inboarding the rear leaves for simplicity's sake and do a shackle flip/super long shackle for the needed lift.

I also think, for now, I'm going to leave it a long bed and rough in a cheap flat bed till I can figure out how I want to cut it down.

 

[TerryD]

So does everyone agree that the 2wd frame will work ok?

 

[howdiy]

It works so far for me

After you get the engine crossmember and front spring hangers done everything else is a breeze.

I think the 2wd rails are a little wider and my shackles may rub when the front flex is maxed out but I'm not worried about it right now

PS: heres my thread incase you missed it

http://coloradok5.com/forums/showthread.php?t=246110&highlight=howdiy

 

[Russell]

2wd rails and 4wd rails are the same part number IIRC. Probably have to drill a couple holes to move mounts / members around, but things will work for you.

 

[original balzer]

Everything Kert said.

Important note; The fist crossmember being differnt the ord sterring brace doesnt fit. I think it would be foolish to not swap that crossmember and add the brace while you have it torn appart that far. Or fab up a brace that does work with the 2wd crossmember.

Also the engine crossmember bolt holes are differnt, and so are the holes for the motor mount towers.

 

[howdiy]

I also forgot to add, the 4wd engine mounts do not fit in the 2wd frame, the 2wd frame is shorter

 

[TerryD]

Alright, thanks guys! I was going to fab up the cross members and steering box brace anyways to help stiffen the frame some. Hopefully I'll get some time with my truck this weekend.