M59 speed issue.

[Mackafd]

where there options as far as transmissions. my ride home today/ first ride in the truck was a long hot ride in 5th gear going 35mph. was that all the m59 trucks could do??

 

[wreckerman893]

Were you in Low or High Range?

Sounds like a silly question but 35MPH is the top speed in Low Range in most older military trucks.

If the lever to the right of the drivers seat is down on the floor then you are in Low Range.

What RPM was it turning? Was is smoking and/or skipping? Is it a gasser or multi-fuel?

Any version of the deuce should max out around 55 in High Range unless you are having fuel/air issues.

First order of business would be to change fuel filters and check the air cleaner for restrictions. A diesel needs clean fuel and plenty of air to perform to it's max potential.

If you want to keep the duals you can go from 900x20 tires to 1100x20 for a few more MPH. Super singles will give you more MPH but you will suffer on pulls.

 

[Mackafd]

Ok has engine running decent. Transfer case lever pulled up in the up position. I have no tach but the engine was screaming at 35-40 that's was as far as I was going to push it of flat roads. New 9:00-20 tires. Also the truck dogs bad on hills was going 35 hit an hill and had to down shift down to second more then once to keep going. Many really pissed off drivers behind me..

 

[NDT]

The OA331 should do better than that, but is a dog on hills. Give her a tune up and filter/oil change and see if there is an improvement. You can install the overdrive transmission from the multifuel, but that just makes the top end worse.

 

[xm708]

any chance your m59 has the original data plate on the dash specific to the m59 ? if so any chance of a few pictures of it ? looking at a dump with no plate no cab protector tool box or mud flaps

 

[Mackafd]

I will see what I can do when I get home tomorow. There are a few tags on the dash but very little specific to the m59

 

[jatonka]

The gasser deuces were rated at 60 MPH in 5th gear. You probably have a fuel problem. As long as the truck was empty, you should have been able to do at least 50-55 MPH. Be sure gas is fresh, using non ethanol only or you will be rebuilding the mechanical fuel pump VERY soon and most assuredly. I have some experience with the 331 Continentals and they are higher horsepower than the Multifuel engines that replaced them JT

 

[Mackafd]

The old owner lost some of the parts to the fuel pump so I installed a electric one high flow. I want to check with a tach on my rps. Also woundering since the speedo is in the transfer case is it set for low range and then high range you add mph..

 

[Mackafd]

are you going to the Gilbert show. I would love for you to take a look

 

[Mackafd]

 

[pigpen60]

The speedo is on the output side of the transfer case so the speedometer is a direct read.