The Stovebolt Site Forums The Parking Lot Big Bolts Powerstroke Diesel swap into 58 C60

Nice job, Mark. I'm coming over for a ride!
Victor

Mark,

I you're coming to the show in Winchester, plan on overnighting with the Stoveblot group. They set up RV's and tents on the grass field and make a weekend event...lots of good food, drink and fellowship as well as kicking the tires. It's one of my regular events that I don't miss...

Hope to see you there!

Mike B

Went out today to the mulch yard and took pictures to prove I use the truck I need to remove the foam off the front bumper, but I'm still walking on it while I "fine tune" a couple things under the hood.

I also took note of speed and RPMs to determine what the gear ratio is in the rear axle. At 40 MPH I was turning 2250 RPM (4th gear 1:1). The tires are 40 inches tall so that calculates to the 6.40/8.72 combo. I found a Mitchell overdrive unit (18%) that I'm going to stick in the driveline so I can (hopefully) get first gear back. According to my fuzzy math the Mitchell unit should effectively give me a 5.24/7.15 combo. I should then be turning 2800 RPM at 65 MPH in 4th gear. The transmission is a 5 speed (.77 overdrive) so that should further reduce RPMs to 2150 at 65 MPH. I think that would be a very comfortable ride.

Am I doing my math right?

https://plus.google.com/photos/115050180406101428512/albums/6015901219714536369

Have you looked to see if a better geared center section for your rear axle is available? Or swap an entire rear axle.
That would be my first choice, and only then an auxiliary transmission if more or faster gears are still needed.

If I'm not mistaken a Mitchell overdrive is not very heavy duty? That said if you have one and it is in good shape it could be useful assuming it stays together in your 2 ton truck with plenty of torque.

Grigg

I don't know enough about the Eaton 2 speed that's in the truck to determine if a higher gear set can be found. There's no tag that I can find on the axle, its an electric shift is all I know.

I was looking at this web page that seems to imply there were 2 axles (15K and 17K) and the heavier axle was only available with the 6.40/8.72 combo. My first choice would also be a gear set since the 15K axle listed on that page had the ratio range I'd effectively get to with the Mitchell unit.

If I were to completely change the rear axle I'd need to find a six lug axle since I have alot of money wrapped up in the wheels and powder coatong.

http://www.chevyc60.com/the_rear_axle_page.htm

Forgot to mention I scaled the truck again at the mulch yard now that the dump bed is back on; weighs 10,120 lbs (7800 lbs wihtout the bed). Last year at this time it weighed 9,000 lbs even so the new engine/tranny combo added about 1,000 lbs. I probably added 100 lbs in sound deadening too which accounts for that extra 120 lba.

I can't tell from the pictures if you have 6 lug stud centered "Budd" wheels, are your rear wheel nuts two different parts?
Of do you have hub centered wheels?

If stud centered Budd wheels you have lots of newer (but not as many brand new) axle options. If hub centered "Motor Wheel" then you have limited axle options (only old stuff).

In any case do some digging and see if you can find the faster gears for your existing axle. That will be simpler, lighter, more reliable, and cheaper than installing the Mitchell.

I don't know what to tell you exactly to look for.. If you start calling junk yards someone will eventually know what you're talking about and help you figure what model axle you have and what center section you need, possibly interchange from even newer or other model Eaton axles than what your truck came with.
One of my favorite Junk yards for old and newer driveline components is AD Weddle in Roanoke, VA, Mike might be able to help you out 540-345-2331

Grigg

Mark,

The 15000# axle was the GM Corporate axle that had vacuum shift. The 17000# axle was the Eaton axle and they had electric shift.

I found a 6.14/8.36 Eaton rear center section for my 1957 10500 Fire Engine. With my 1:1 5th gear I run in the mid 60's all day long, I'd be underpowered to turn any higher gears.

Mike B

I found a couple of "Grummann" bread trucks,with radial 19:5's. These are 6-bolt stud-centered. we didn't have a tape measure along,to verify the bolt pattern. Billy W.'s VERY interested,since both are equipped with the 4BT's. That's the swap he's considering for his '59 Viking 60 Bus,since his wheels 6-lug stud centered), are all RH's. These trucks use a brake booster,attached to the power steering pump,as well. Unfortunately,both trucks are 4-speeds. There's another one there,also,with 8-lug 19:5's,but it's Ferd (V8 gas) powered,so the wheels may not be the same as G.M.

Thanks for the help guys. I called Mike at AD Weddle (super nice guy, thanks Grigg) and he asked questions and for me to send pics. When I mentioned the "bolt on" rear cover that seemed to deflate his enthusiams a little; meaning there may be few if any options.

My axle is Budd, stud piloted. I know some Ford F600 and F700 through the eighties ran the 6 hole stud piloted with the same bolt circle, but I don't know if the WMS widths are close in measurement.

Here's the pics I sent to Mike at AD Weddle:

https://plus.google.com/photos/115050180406101428512/albums/6016166230405970849

Mark,
International also used the 6 bolt patern up through the 90's. Isuzu NPR rear axle is the same bolt pattern but you have to change the studs to american thread. The gas 5.7 ones have 5.38 gears in them. There are no 2 speeds in isuzu trucks though. That is what I am running in my 57. If you want a measurement on the with I can get you one. I could measure my 59 GMC and see how close it is.
Shane

Lets hope Mike comes through and can find better gears for what you have, that sure is easier than swapping the whole axle.

Grigg