43 Marmon Herrington 4x4 top speed

[42Ford M-H]

Any info on a safe top speed for the 4x4 drive train? The war tag says a top speed of 40. I'm not sure where they get that number from. Gear ratio? I'm shooting for 55 mph once I change gear ratios etc... or maybe even stick in an overdrive. I'm assuming if i take it easy that 55 won't damage the 4x4 components but I don't know that for sure.

Thanks in advance for any info.

[rotorwrench]

Most convoy speeds were low for WWII time frame. Although they were never what a person would refer to as fast, I think you could get a bit more out of them without hurting any of the drive train. If the vehicle was set up for snow plow or blower then the speed would be as fast as you can go without doing any damage to the accessories and 40 mph would be in that bracket.

[truckdog62563]

I'm thinking your top road speed will be more a pure function of final drive ratio and tire outside diameter, rather than of the M-H components. When Chuck Mantiglia rebuilt my F-3 axles he installed his custom 4.11/1 gear sets (which I don't think will fit your axles). When I get the truck done I'll have 34" or 35" tires that will yield more road speed than I'll have guts to ask of it.

I don't have any 1943 truck data, but the below 1942 chart from the Ford Reference Manual ought to be close enough. M-H would have spec'd the lowest final drive ratio available I believe which would be the 6.67/1. If you find a couple sets of 5.14/1 gears and team them with 38" tall 8.25-20" tires you'll be set to go. Note that the chart's figures are for 2500 rpm operation. Stu

[42Ford M-H]

Truckdog you are the man, thanks again for sharing your wealth of knowledge. I've been keeping my eye open for some 5.14's. I'm leaning towards taking my axles to Chuck to have him go thru them, and possibly put in the gears. He's probably has 2 sets of gear.

You wouldnt happen to have any info on the gear reduction drive for the Sno go's would you? more specifically I'm looking for the ratio of the reduction. I'm looking at the possibility of flipping it around and using it as a overdrive. Which if i go that route I won't need the 5.14's. Physically I think I can get it to work, Still not sure about the internals of the unit. I need to tear it apart and look for thrust bearings etc...

[truckdog62563]

I believe Chuck has said that he has NOS 5.14/1 sets. As for the SnoGo under-drive, I know nothing about that. But Chuck will know. Good luck with it. Stu

[Barry-ct]

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I had a 43 GMC 6x6 and it would cruise at 55 no problem all day, until you got to a hill. We have a few hills here in Conn. where she'd get down to 15-20 MPH, but would climb them. The trucks were never made for speed, and were designed for off road use on undeveloped roads. Their weight capacity was also cut in half. A 2-1/2 ton trucks load capacity was 2-1/2 tons of cargo off road, 5 tons over paved roads. A truck like yours was never considered for "Combat use", but for on base use.

[42Ford M-H]

I was reading somewhere that the 4x4 M/H conversion raises the load rating. I could be wrong. Can't see myself hauling many heavy loads, but it would be fun to get a load of gravel once in awhile. We have our fair share of mountains in NY.

[40 Deluxe]

Be sure to run dual straight pipes up the back of the cab so you can hear that flathead cackle under full load!

[rotorwrench]

I don't know if the underdrive would be a Brown & Lipe or something MH came up with. There were a lot of "Brownie" type over/under drive set ups back then for all sorts of uses. MH certainly made a lot of their own axle assemblies.

[1952henry]

Don't believe it is a Brown-Lipe. Can't recall the name, but it is uncommon.

[RobR'35]

Watson perhaps?....

[alanwoodieman]

pictures of a former military fire truck--notice the under/over drive

[rotorwrench]

Marmon Herrington made a lot of the fire trucks used during the war. I don't know if they were all wheel drive or not.

[1952henry]

Some were awd some 6x4. Depending on the manufacturer some had a splitter like the above picture and some had a splitter by the tandem.

[GB SISSON]

Here's a picture from 'vintage photos thread' on FTE

[42Ford M-H]

Here is a pic of the drive train. Dirty and grimy atm, once i get it cleaned off I'll post a pic of the name and patent date. Patent date is April 1918

[42Ford M-H]

I forgot to mention I opened the under drive to check out the gear ratio. LOL 5:1

The older gentlemen i bought it from told me a quick story when i was loading the truck. Apparently his neighbor was bragging he could tow that backwards with his new chevy 4x4 I'm guessing late 80's early 90's. So they chained them up, he put everything in in low gear including the under drive, let out the clutch... Got out of the truck and was talking to the guy thru his drivers window as he was getting towed backwards.. LOL

[cas3]

the wwII gmc 6x6 had overdriven 5th gear in the main trans. not the same in the marmon i would guess.

[meric42]

With my experience driving WWII 4 X 4 vehicles I have found that at speeds much above 45 mph these vehicles can become a bit of a handful to keep in a straight line. Once you have driven them for a few hours you certainly know how tiring (and Noisey) it can be, JMHO.

[42Ford M-H]

[rotorwrench]

Cotta Transmission Corp still exists but I don't know if you could find anyone there that remembers that old unit. There in Beloit, Wisconsin now days.

[1952henry]

That's the odd name I couldn't think of.

[38 coupe]

Since you already have an auxiliary transmission, the Cotta unit, you can swap in a different aux unit that has an overdrive. You want to look for a small Watson or Spicer unit. Here is a spread sheet of aux boxes and ratios I put together a while back. The 6000 series and larger Spicer units get pretty big and I wouldn't try to use one. Keep an eye on craigslist and ebay, you will eventually find one that will work for you.

[42Ford M-H]

If I read this right, those units have low, medium and high range?

[42Ford M-H]

Thank you for making the list btw

[42Ford M-H]

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which one is easier to find parts for? Spicer or Watson?

[38 coupe]

Originally Posted by Sceptre155

which one is easier to find parts for? Spicer or Watson?

Sorry for the slow reply.

None are easier to find parts for, the units in the list haven't been manufactured for 50 years or more. The most common boxes seem to be the various versions of the Spicer 5831, followed by the 41 through 48 Watsons. As long as the gears and case are in decent shape you are in OK shape. The bearings are available and you make your own gaskets. The expensive part can be the yokes to work with your drive shafts, if needed. Also, finding a shifter can be interesting.

[BouncinBetty]

Just seen this , been away a while , my dump truck does not have the underdrive unit. No sign of it .

[BouncinBetty]

My Dump truck does not have this extra gear box , wonder why.


Any idea where I could get the tipping gear ?

[1952henry]

Plow trucks had it so the blower, which had its own engine, could chew through the snow whilst the truck provided the tractive force without burning up the clutch

[BouncinBetty]

Thanks for that it makes perfect sense now , mines a dump truck so would not require it.


Regards.

[blucar]

Originally Posted by 42Ford M-H

I forgot to mention I opened the under drive to check out the gear ratio. LOL 5:1

The older gentlemen i bought it from told me a quick story when i was loading the truck. Apparently his neighbor was bragging he could tow that backwards with his new chevy 4x4 I'm guessing late 80's early 90's. So they chained them up, he put everything in in low gear including the under drive, let out the clutch... Got out of the truck and was talking to the guy thru his drivers window as he was getting towed backwards.. LOL

The above comment brings to mind a demonstration I watched at a Ford Dealership in Idaho in the mid '50's.
Ford was touting the new automatic transmissions they were offering in the F100 pickups. Ford claimed that the automatic trans would pull a stick backwards, two F100's were hooked together, back to back.
No matter what the driver of the stick trans did, the automatic would pull the stick backwards with it's tires smoking.
Plain and simple, an automatic will put more usable torque to the wheels..

[rotorwrench]

If you change ratio of final drive. Make sure it affects the front and rear axle alike. This requires the gear change box to be between the engine and the transfer case. I can't really tell if the underdrive is placed that way or not due to the photo not showing placement well enough. If it is only placed in the rear drive then it can only be operated while the front axle is disconnected for rear wheel drive only. Both axles have to go the same speed. I know that Marmon Herrington added in a slip ratchet set up in the front axle drive with a lever to operate it but there is no way to lock out the front axle hubs like a later model 4WD vehicle.

[42Ford M-H]

Underdrive was between the motor and transfer case. And was only for sno go trucks as far as I know.

[42Ford M-H]

honestly at this point I think it would be easier to changed transmission to something with overdrive. For better high way speeds. What transmission I have no idea. Needs to have pto for dump box. I’m looking to do the same thing maybe at some point.

[rotorwrench]

You'll have to look into a New Venture NV4500 or an old Clark 280VO if you can find one. I have no idea how hard it would be to adapt but the NV4500 is a 5-speed OD transmission with PTO cover plate. The old Clark OD types are hard to find.

A gear vendors OD on an NP435 is another possibility. Most of the older 1 1/2-ton trucks had a 2-speed rear axle so they didn't need an overdrive.

[FireEngineMike]

I thought the 2-speed tonner truck axles were under-drive with a numerically higher gear for more low end grunt.

[rotorwrench]

The Sno Go is a 4WD so it can't use a 2-speed axle unless some company makes one for 4WD front end and I've never heard of one. These old trucks use the old Timken axles on both ends with the front one being modified by Marmon Herrington to work for 4WD.

There are other 5 and 6-speed transmissions but most of the newer ones don't have a removable bell housing so they would be very difficult to adapt.