Need opinions on building new cross member

[smokkey1]

for the transfer case. I have some 2x2 3/16 square tubing, would that be ok to use? Or should I use round tubing and if so what size should I use? I also have 1/4 plate for the mount for the transfer case and some angel Iron to attach to the fame rails. basically what I want to know is there any disadvantages using rectangular tubing vs. round tubing? I'm going to be clocking the transfer case up a few degrees and build an skid plate. I was going to clock it up between the frame rails but I'm going to wait awhile till I can afford HAD drive shaft.

 

[smokkey1]

TTT... I changed my mind I'm going to full clock the transfer case but. But I still what to know is there any disadvantages using rectangular tubing vs. round tubing for the cross member?

 

[dyeager535]

What I've learned is that its important to have a nice wide bolt pattern for the frame ends, and that to clear the front output flange/driveshaft, you will have to raise the front output by about 2-3", which I assume is totally possible with clocking. At least with my later 205 setup, the output flange is perfectly split above and below the lower edge of the frame where you bolt a crossmember up.

If you run round tubing, I would think a flat piece welded onto the "front" (leading edge) of the crossmember for the trans/t-case mount would let you clear the driveshaft better, and the torsional rigidity(?, I'm no engineer) of the round tubing would be better at handling weight hanging off of the leading edge. I don't think I'd want that flat piece very long though, lot of weight sitting on it.

Round or square, if you want to run the engine mount directly into the crossmember, you end up having to cut large holes on the bottom side to access the nuts.

I bought some big U-channel (3" inside width) to make a crossmember out of, but again, without clocking, it was unuseable in my case.

 

[smokkey1]

It's going to be something similar to this.

 

[dyeager535]

That's about exactly how I'd build one if I were going to.

Don't see any reason that design won't work, and don't see any way that it needs improved. Exhaust MIGHT be an issue, have to go under more than likely, but that can be pretty easily worked around.

 

[smokkey1]

that's big83chevy4x4 old cross member. So I should just use round tubing instead of square tubing.

 

[dyeager535]

I would think round is the best thing to use. Our frames are flimsy, that crossmember I'm sure sees a fair amount of twist. Looking at the stock crossmembers, GM did a variety of things to keep them rigid over the years.

I know there are people here that can cliarify benefits of round vs. square, but torsion bars to my knowledge are round for the most part.

 

[smokkey1]

thanks for the help. what size round tubing should I use?

 

[dyeager535]

Beyond my expertise. When I was looking at material for my crossmember, I just went for some stuff that was obviously thick enough to support the load that was going to be placed on it, but that wasn't an expert evaluation, just "this should be strong enough".