The Stovebolt Site Forums The Shop Area Engine Shop Rear end options for 46 1/2 ton

Does anyone have experience with which six lug truck rear ends will fit under a 46 1/2 ton?
The original running gear is gone from this truck and I would like to put a GM 6 lug truck rear end but it is narrower by several inches than the Advance Design truck.
Anybody else run into this?

Thank you

A rear end that is 61 inches wheel mount to wheel mount should fit fine. That being said, I got a F**D 9 inch full floater rear end for my 1940 that was 61 inches wheel mount to wheel mount. When I bought the rear I specked out 31 spline axles, a 6 lug on 5.5 bolt pattern, and 12 inch X 1.25 vented rotors. Those large rotors may be overkill on a 1/2 ton, but should be able to stop any load without overheating.

The 9 inch full floater is a great setup. You can get it in any width, or gears you can imagine. It is stronger than a dana 44, and a lot stronger than a gm 10 or 12 bolt.

Around the bay area, rear end work is real expensive. You may be able to find a suitable rear end from a boneyard, but you will still have to Find one that will work, pay a million bucks for it, clean it up, rebuild it, possibly shorten it...

As far as a parking brake... you could either spend a lot of money for calipers with the cables, or you could get a pinion mounted brake which would probably be eazier to adapt to your stock floor lever.

This truck has F**d 9 inch rear end under it.
How do I go about getting 6 lug axles?
I was thinking about getting the E brake that fits on an SM420 since I have one of those trannys here.

Thanks

Forgot to mention that 61 inches is for a 1 inch inner offset... meaning if you use a 7 inch wide rim you would have 4 inches of backspacing, and should center the wheels under your fenders. The 61 could change depending on the offset of the wheels you are using. Please take your own measurements.

Hey truck, I have a full floater so it is a little different than your setup. I have axle shafts that are splined on both sides and slip into a drive hub on the wheel side. You can see this type of axle by running a search on ebay for an "IMCA Modified 9 inch".

You should be able to pull the axles out of your 9 inch and have them redrilled, or get new axles from one of the rear end places like Currie enterprises or Moser.

Truckasaurus...I had the same issue with my '42...I tried a late '60s Chevy Blazer 3.42 rear (6 lug) but it was 2" too wide...I searched the junk yard for a fit but no luck. I ended up using a 70-72 Nova rear on which I had the lug plates redrilled for 6 lugs (had the odd holes welded in and ground flat). Seems to work fine.

My 46 half ton is running a '65 chev 6 lug rear, fitted with 3:08 ratio gears. I've previously ran a 57 pickup rear 3:90 ratio plus a couple other torque tube units. 6 lug is fine only if you need to keep original rims, lots of other rears will fit but are 5 lug.

I want to keep the six lug for continuity with my other truck.

I thought about a Nove rear end but a car rear end seems a bit light for a truck that will get worked.

JlMerit, did you have issues with width on the truck or did you somehow modify it.
My panel seems too narrow to fit something from the later trucks.

Bigbadswingdaddy, sounds like you and I are on the same page, I have my stock 16s widened to 7 inch with 4 inch back spacing.
235/85-16s are a perfect fit on my AD truck and that's what I'm looking to run on the panel as well.
Would it be possible to check out your truck sometime?

Thanks everyone, some good tips here.

Truckasaurus

I didn't realize we were talking about a panel truck. I was assuming a stepside. I'm not so sure the widths are the same. One Man who would know is Barry Weeks.

You can come and check out my {truck} anytime. It is a bit rough right now, and is missing the bed. I am still gathering parts for my total driveline swap, but my truck is still driving with the original engine and transmission and rear.

Bigbadswingdaddy.
I would be surprised if the widths differed from 1/2 ton panels to 1/2 ton pickups.
It seems unlikely that GM would make more work for themselves, particularly with the much lower prodction numbers on panels and burbs.
I'll take some more measurements and send you a pm to see about checking out your project.
Mine is a long way out but it seems like the rear end is going to be the biggest stumbling block.

Hey Truck,
I went the other direction. I kept the torque tube housing in my 46-n-1/2 and put a "new" punkin in it (55 truck 3:90). Steppenwood has some great shots of his mod and I have a full set on my photo link as well.
With this option you can keep original axles so wheel offsets pose no problems and I too am running 235/85/16's.
Might be able to find someone giving away an old torque tube; see them from time to time on in the swap meet.

Cavebull

Cavebull

What you may need to do with your panel after finding the rear axle you want, is to adjust width with wheel choice. There are lots of shops around that can move the wheel center in or out or make up custom rims. And with the rears I mentioned, they all fit inside the stock fenders.

Hey Cavebull,
I'm not opposed to running a torque tube but weren't the pre '47 units different from the later Advanced Designs.
Would I be limited to the early crash box tranny?
There is currently no driveline in this panel and I have a 261 and an sm420 I was going to use.
I'm just looking for the path of least resistance and don't want to chop anything up.

JlMerit,
I have rims here that were stock 16s and I had them widened to 7" with 4" spacing in the back and front, basically zero offset.
By my measurements the later '55-'62 housings are too wide.

Did you run stock wheels under yours with the '57 rear end or would I have to bring the back spacing in?

Thank you

I have enough trucks that I would like to stick with the same wheels.

Truck, the widths may not have varied, but the amount of clearence may have. The fenders on the panels and burbs are a lot more narrow than the ones on the pickups.

Trucka-you can see a pic of my truck in the gallery, Jim's 46, in the last photo you can see front and rear wheels.

I'm running the old 15" artillery wheels, backs were widened to 7" I think, it's been a while. Also I'm running radials all around so you can see in the photo there is enough room. It just may be that the panel is narrower, can you measure the width at the wheel opening, side to side and I can compare with the pickup?

I think the move to open drive was one of the best things I've done on the truck. Only then can you even begin to think about swaping tranys etc. As someone mentioned Steppenwood changed his stock rear axle to open via a pumpkin swap. THis would eliminate all your wheel issues. I wanted more ratios and the modern brakes under my truck plus I got lucky as a friend already had this 65 rear axle. I also have 57 pickup brakes on stock front axle, that's and easy bolt-on.

JiMerit, This is an interesting thread for me. My 53 panel is in the middle of a restoration. I have a 261 ready to drop in. I have the original 4 speed and torque tube with original axle. In my garage I have a spare 3:07 rear end and drive shaft out of my 69 chevelle. You say you have similar gearing in your truck. How is your bottom end torque? I'm not too keen on these 4:11 gears and I don't plan to work my truck too hard.

The panel has a 12 inch wide wheel well, this is from the frame rail to the inside lip of the rear fender.
The frame rails are 44 inches apart and the rear end that is in it measures 51 inches from backing plate to backing plate.
It's a pretty good fit

Inside edge of the pickup fender to frame is 13" to 14", so just a bit wider than the panel.

53panel, re the 3:08 bottom end, not the greatest, around 3:50 would be ideal. In my case a friend had this rear end and FREE was right in my price range. It was 6 lug and very near the same width as the 57 pickup rear I took out. Here in this very flat land and my light weight 46 pickup (also 261) I can get by just fine with the 3:08, your panel may not like that ratio.