The Stovebolt Site Forums The Shop Area Engine Shop Torque tube swap

I have a 1945 GMC 1/2 ton. I have a 302, with a saginaw 4-spd, 3:11 gear trans. I need to swap out my torque tube leaf spring rear end. Any suggestions? What should I look for (ie: year/make/ratio's) Is this a direct swap project?

That depends on what rear end you use. I put a Camaro ('82) in my '48, and it fits fine. You'll have to have a drive shaft made once you get the rear end and tranny in place.

Baldeagle,
THanks for the input. WHat gears are in that rear? Is it a 6-lug? DId you have to modify anything, or was it pretty straight forward? CAn you email any pics of the swap?

The rear end I used is a 3.73 limited slip rear end, and the axles are five lug, Chevy pattern. I had the work done by a guy who's been doing this a long time, but I can tell you that they used the original springs and welded up triangular mounts for the rear end to sit on. They welded mounting points for the sway bar support struts, and that's about the extent of it. The length of the axle was almost identical to the torque tube, so the tires should sit in the fender wells just fine.

Here's a shot from the rear.
[img]http://www.utdallas.edu/~pauls/trucks/images/rear.jpg[/img]

and here's a closeup of the left side. You can see the sway bar support strut mount and part of the rear end. I don't have a shot of the actual mount that the rear end sits on. I'll have to take that this weekend.
[img]http://www.utdallas.edu/~pauls/trucks/images/left_inside.jpg[/img]

Paul, looks like disk brakes? Are those stock Camaro parts? I suppose if you had the hubs re-drilled for 6 lug, you would screw up the brake rotors? How bout it Phat? I want to keep my 6 lug skinny 16 inch tires!

Baldegl--

Nice rear end -- did ur guy have a solution for parking brake with the discs?

Baldeagle,
THanks for the pics. I am looking forward to the additional pics you are going to take this weekend. Do you mind me asking how much did you pay for the rear end? Who made your driveshaft? Is this something that can be measured once the trans and rear are installed, and then have a driveshaft company make one up special? I am also interested in the parking brake questions as well.

Ken I dont recommed the late model camaro firebird rear it not a very strong unit and has a problems with carriers.The ones i have used also were to narrow and required offset wheels.I have never seen the need for disc brakes or a sway bar either on the rear of a pickup.There is not enough meat to drill them 6 lug either.Have built a few with sway bars on the rear but ended up removing them.I just tightens up the back of the truck to much.Formula1 If you do change rear end dont put the rear in the stock location ITS WRONG from the factory.You need to mount the bed and move the rear back 1 to 1 1/2 inches to were the tires are centered .Only then do you have a driveshat made.I see your from CT. Camerota truck parts will make you a driveshaft 860-763-0896 is the enfeild ## Dont have a shaft built till you put the bed on as most times the rear end is in the wrong place if it was not mocked up correctly.Best 6 lug rear i have found has been the 80's 4x4 chevy/gmc.Best 5 lug has been the 9inchFQRD.

Thanks Bruce . . . guess I'll stick with the Blazer plan.

Phat, thanks for the info. You suggest relocating the rear end due to improper original location. Does this mean, relocating the shackle mounts? Can you explain further. Also, you suggest a 6 lug rear out of an 80's 4x4 chevy/gmc. Can you get more specific on years and what gears should I look for. SInce you live in CT also, where would you start to look for a good rear end? FYI, I have a 302 and plan on getting a Saginaw 4-spd with a 3:11 first gear.

Hey guys,

I'm real ignorant when it comes to this stuff, so please bear with me.

I own a 47 gmc 1/2 ton, and am considering changing rear ends (you may have seen my other question here in this section)

if I were to take out my torque tube, do you need to change any thing a the output of the transmission . special seals? any thing wierd?

I too, would like to keep the 6 lug hubs for the tall skinny tires.

I have a 1967 chev 1/2 ton I am using for parts, it has a 6 lug pattern, would that pattern be the same as my 46 GMC?

Thanks guys

Ken - yes, those are disk brakes. This is a stock setup out of an '82 Camaro.

bznhafdzn - if you look close, you might be able to tell that the emergency brakes are hooked up. They're tied in to the stock brake system. The cables come off of the same connection point on the two sides of the rod that crosses the frame right behind the cab. I can use the stock adjuster.

Formula1 - the rear end cost me $175. The work was a lot more than that. The driveshaft was made by a local company. Yes, you have to get the tranny and rear end in place first, then you measure for the driveshaft. Like Phat says, you need to properly locate the driveshaft. We did it by taking measurements on another AD truck and comparing those to mine, then determining where center was. We did *not* relocate the shackles. Those are stock and in the stock position. We fabricated new mounts for the rear end, to locate it on the springs where we wanted it located.

phat - what can I say...different strokes for different folks. Not sure if you consider the '82 a late model. This rear end is about 1/4 inch wider than the stock AD rear, so it didn't require offsets or anything like that.

I'll take some specific shots this weekend to show how things are hooked up. The e-brakes, the springs to the rear, that sort of thing.

I have 46 Chevy, used 89 Camaro rearend in stock location, not back 1 1/2 inches. I think it is AD trucks that have to relocate. I toyed with the idea of using my original 46 housing and putting in a 57 3.90 pumpkin to keep 6 lug, but I ended up w/ 5 lug discs on front so I decided to use newer 5 lug rearend.

Brian, yes that 6 lug pattern is the same.

As promised, here's some shots so you can see how my rear end was done.

Right side emergency brake cable. Here you can see that the cable is mounted to the stock system:
[img]http://www.utdallas.edu/~pauls/trucks/images/right_e-cable.jpg[/img]

Right side e-brake. Here you can see how the cable is routed to the disk brake.
[img]http://www.utdallas.edu/~pauls/trucks/images/right_e-brake.jpg[/img]

Right side spring mount. Here's you can see a little of how the springs are mounted to the axle housing.
[img]http://www.utdallas.edu/~pauls/trucks/images/right_spring_mount.jpg[/img]

Left spring mount, from underneath. This gives you another view of how the springs are mounted.
[img]http://www.utdallas.edu/~pauls/trucks/images/left_spring_mount.jpg[/img]

HTH. If you have any questions, just ask.

This is a photo of the 1980 6 lug 1/2 ton 4x4 or Blazer axle under my 51 Chevy pu I installed 6 years ago.The axle saddle pads are a Mopar part I bought at the local speed shop along with the u- bolts .The bottom plate is off an S10,the holes had to egged out slightly to fit.The stock part number rear shock even fit onto the S10 plate shock stud.The original spring pads on the top of the axle cleared the ubolts so I left them in place.Really simple ,don't even need a welder.Get the pinion angle right, tighten the ubolts and drive to the welder if you have to.Cheap and easy.
[img]http://pstr-m01.ygpweb.aol.com/data/007/12/70/DB/46/iNBuZ380rkAoi6lO88USZApIeWSboNKl0180.jpg[/img]

[ 01-19-2002: Message edited by: Tony ]

Tony, Great looking rear end, but the tire lettering needs some whitewall cleaner..

Baldeagle, are you going to install U-bolts to hold the spring and the axle together?

You can't really see it in the pictures, but the triangular mount that is welded to the axle housing extends several inches in either direction above the springs. The U-bolts go over that surface and then around the springs. So they are held on to the springs with U-bolts, it's just not easy to see it in the pictures. If you look at the right spring mount picture, you can see what I mean.

Paul i think what Tony is getting at is if you have a spring break (or the weld on the rear) your gonna go for a big ride side ways.The best methoud is to capture the rear and the springs all together.Say just one leaf breaks at the center bolt hole and the 2 half sneak out the u bolt will fall off and the rear will twist .Not a real fun thing.The guy did some nice work for you.

Hey Tony . . . I used up a pair of of Kelly Chargers like that only in 14" x 235 in one weekend on my 49 when I first got it running. I remember buying them at Costco and they wouldn't mount them for me because they couldn't get the truck up on the in-floor jack. Front bumper was too low to the ground. Tried to just get them to put a jack under the rear differential and they said it would break it :rolleyes: . . . I threw the tires in the back and went to Les Schwab! Made it to SIR late Friday afternoon and I broke a rear U-Joint that weekend too . . . after finally figuring out how to get the rear end to hook up when shifting into second. But, that was a hot rod, I only do not rods now . . . no V-ates for me any more. :p

Ken, no worring about a stock 261 with a posi rear smoking the tires bald.Yes, Phat's comment on the u bolts is what I had in mind when I did the rear axle swap. I like the clean look of Baldeagle's welded up spring saddles though as it eliminates the shims or blocks used to get the truck to sit the way you like it.

Just wanted to say thanks, I have picked up many tips from this topic.

Thanks to all who are participating!

Brian