The Stovebolt Site Forums The Shop Area Driveline rear end change

I can't seem to locate the post on this so I'll ask the questions. It is my understanding when changing from a torque tube to an open later model rear end you need to do the following. 1ST remove the torque tube assembly. Next, I think I read that you need to turn the springs from front to back to center the new rear end (1969 chevy truck.) put the rear end in place and measure and center, and get the pinion angle correct. Put the new spring perches in place and tack them in place. After all measurements are in place. Weld the perches in place. put the ubolts in place and tighten everything up. I know about the brake lines and ect. It is also my understanding that the emergency brake won't work with this swap. If this is correct please let me know. I'll deal with the emergency brake when I get this done. It will be a 6 lug to 6 lug swap. Thanks a million. Steven

I've already swapped the ring gear and pinion to a 3:90 and had a new drive shaft made. Don't know if it will work or not. Just have to wait and see. The weld broke on the torque tube so I'm going with the later model housing. Forgot to mention that.

The stock "spring perch" was a pivot. Works with the torque tube. With an open drive shaft the axle housing needs to be clamped firmly to the spring(new "U" bolts and plate required) the spring perch is welded to the housing( to secure the pinion angle). If you want, drill the perch to center the axle in the wheel opening(yes the center pin will be a bit off, but it will be "off" when the springs are reversed). No real good reason to reverse the spring.

just a question. Does this mean I can use the same torque tube housing just change the way I use it as in putting new spring perch and u-bolts and plate? I hope so it will mean a lot less work for me. Thanks, I hope I'm understanding the\is correct.

Just to know. I found an article in "Jim Carters" online 1947-1954 Rear Spring Alignment. It says in there if going with a late model rear end to swap the springs around (front to back) or you will wind up with the wheels off center in the wheel well. The spring center bolt is not in the center of the torque tube springs, but when turned from front to back will make the spring bolt line up in the center of the wheel well. It doesn't change where the bolt goes through the spring just where it lines up in the wheel well. Maybe someone has done this and reversed the springs. I will try it if I can't use my 49 housing. I hope I can put the new plate and u-bolts and see if that works. Whichever way I will change the gears to 3:73:1. For those who want to know.

As I understand the post. You have an open drive shaft. The "center" pin on the springs is not in the center(true). So turning the spring front to rear will change the position of the axle in the wheelwell. It will move it to the rear. Will it center in the wheel well? You would have to measure to find out. It will move to the rear. The point I was trying to make, was the hole in the perch saddle that sits over the center pin, can be redrilled and make turning the springs around unnecessary(I am a bit lazy, drill two holes, or turn the spring...). If I got it wrong(happens often) and you still have an enclosed drive shaft(torque tube) then the only way to move the axle back wards is to turn the spring end for end. Drilling a new hole in the cast perch/pivot assembly would be unwise. Will this center the axle in the wheel well? It will move the axle to the rear and that might be the look you are after. Regarding the ring/pinion ratio, the only option I am aware of is the 3.55 option. Other options are available with the open drive shaft. But the torque tube and carrier only ring pinion sets I know of are stock(4.11) and 3.55 from after market providers.

The weld-on perches sold by classicparts.com already have the extra holes in them, making turning the springs around unnecessary. If you use the off-center hole, your wheel will end up exactly where the original wheel was located which is forward of the center of the fender opening. This location keeps the mud inside of the fender.
Carl

Used original housing with 59 pumpkin. I turned springs around and wheels are centered.

I'll open a can of worms here but if you look you will notice the actual springs are not "centered" but engineered more toward the front to handle the torque when the rear end "raises up". In order to leave the leafs stacked the way they were I only turned the top two leafs around leaving the others in the same orientation.
Probably not making any sense but that's what I did.

....don't have the number but you can also get perch blocks from the Dodge place with the extra hole and cheaper than a vendor.
Maybe Joe W. is reading this and remembers that number?

52Carl, Since I'm using the old torque tub housing what would I need to do to keep the housing and make it like a later model housing under my truck. I've already changed the carrier to a 3:90:1 and have the 3:73:1 carrier on hand. I guess what I'm trying to do is to find the easiest and best way to do this. Jim Carter says" turn the springs around if I use the later housing. AT the present I have the original housing using the later model carrier (open drive) If just buying the new perches, with the off set hole and most likely new u-bolts is the way to go. Let me know what you think when you have the time. Steve H there are a number of ratios out there that work with the torque tube housing as long as you go to an open drive which is what I have. you have to find the right model and change the whole carrier. I did it and it works. Only trouble is what I'm having now. Broken weld, not too dependable. The spring perch that broke on mine was the one with the rubber in it. Hard to weld up good. I'm just trying to find the best way to do this and be reliable. Thanks to both of you. Steven

Achipmunk, thanks for coming in.That's what I need to know. Someone that has done the springs around trick. I realize the center pin is not "really" in the center of the wheel well. Just wanted someone who had done it to say so. Thanks ever so much.

....first thing I did was cut the old swivel perches off the housing. Gone! The bottom plates are home made with the help of my machine shop friend who welded a bolt on the plate to fasten my shocks on. I also got tired of the 3.90 and put a Yukon 3.38 ring and pinion but I do NOT recommend Yukon. After trying a new set that whined they sent me another....it was worst than the first so I put the first "new" set they sent back in and forgot about them. Still whines!

....just a side note, Red 49 truck, you can use hardware from a later model, up thru 59 I know, and make the rear wheels self adjusting so you don't have to adjust the rear brakes so often.

Thanks Alvin, Since everything inside the torque tube is new I think it would be in my best interest to start removing the "junk" on the housing and go from there. I know it's really not "junk" The lever shocks are really in good shape. Maybe I'll find a way to use them. Thanks for the info. Steven

Steven,
Here's the deal with the way the original drivetrain/spring "centering" spring pin configuration goes. The torque tube has a rubber mounted pivot which is located forward of the axle tube. The spring pin fits in this forward-located pivot mount. This is why it is necessary to use the front hole of the Classicparts.com spring perches. It will place your axle in the original position, forward of center of the fender opening. If you decide to instead, reverse the springs, you will place the axle in the middle of the fender opening. Some folks prefer that look. I prefer it when folks ask me if everything on the truck is original. I tell them, "Looks like it, doesn't it?" Then I tell them that I have a T-5 overdrive transmission and a 2001 Nissan Xterra rear end in it!
Carl