HISTORY OF THE MUTT

 

The M151 Mutt (Military Unit Tactical Truck) replaced the M38A1. It was designed by Ford and later built by Kaiser, AM General Corporation, and GM.

The M151 is a large departure from previous jeeps, both in looks and design. The M151 has a unitized body with a box frame. It is the same weight as an MB/GPW even though it is a larger vehicle. It has a longer wheelbase, is wider and is lower than an M38A1. It *looks* very stable. But in practice, due mainly to its primitive four wheel independent coil suspension , it tended to roll.

An 'A' arm with a coil spring is used on each wheel. The M151 and the M151A1 have the pivots on the inside of the wheel. The M151A2 changed the rear A arms to pivot front to back. This greatly reduced the tendency to roll over during a high speed turn.

Because of the tendency to roll, the US Army cut the M151s up before disposing of them.

The Canadian Military only used the M151A2 by AM General Corp. and always installed the roll bar kit (ROPS).

The M151 had many kits including:

History

1950
Continental Army Command places requirement for a new 1/4 ton 4x4 with the Ordnance Corps.
1951
Ford awarded development contract.
1952
Ford produces first prototype.
1954
XM151: second prototype.
1956
XM151E1 steel.
XM151E2 aluminum.
1959
XM151E1 chosen for production.
1960
M151 starts production.
1964
M151A1 starts production.
1970
M151A2 starts production.
1978
Production stops.

Engine

It looks like there are at least two engines that are used in the M151.


   Model .............. Ordnance/Continental
   Block .............. Cast iron 4
   Displacement ....... 141.5 cu. in. (2.3L)
   Horsepower ......... 71 bhp @ 4,000 rpm
   Bore ............... 3 7/8 inch
   Stroke ............. 3 inch
   Compression ........ 7.5:1
   Values ............. Overhead / mechanical lifters
   Carburetor ......... Down draft


   Model .............. Hercules industrial (military version)
   Block .............. Cast iron 4
   Displacement ....... 151.5 cu. in. (2.5L)
   Horse Power ........ 55 bhp
   Carburetor ......... Side draft

Drive train

The M151 has a four speed synchromesh manual transmission. The transfer case is used to engage/disengage the front axle only. It does not have a low/high range. Because of this, the M151 has two gearshifts instead of the normal three. From left to right, the first smaller gearshift engages/disengages the front axle, and the second larger gearshift is the gear shift proper (i.e. 1-2-3-4-reverse).

Gearing

While jeeps like the M38 and M38A1 went for lower gearing, the M151 seems to keep the higher gearing of the MB. It is interesting to compare the "Maximum Permissible Road Speeds" for the MB and the M151.


	MAXIMUM PERMISSIBLE ROAD SPEEDS
	             (MPH)
	    M151               MB
	GEAR  SPEED     GEAR      SPEED
	----  -----     --------  -----
	1ST      11     1ST LOW      12
	2ND      21     1ST HIGH     24
	3RD      40     2ND HIGH     41
	4TH      65     3RD HIGH     65

As can be seen from the table, the M151 basically uses the four speed transmission to give the entire high range of the MB, with first being a very close match for the MB's low range first. This gives the basic range of the MB without requiring a two-speed transfer case.

One of the goals of the M151 was to simplify driving it. You can drive it as a three speed with first as a low "off-road" gear

MISC. INFO

Height Open body 52.5 in
  Soft top 71.0 in
Maximum overall width      64.3 in
Maximum overall lenght      132.7 in
Front-to-rear axle       85 in
Wheels      7.00x16 tires
Steering      manual
Tire infl. Pressure Front Rear
Highway 20 LBS 25 LBS
Cross country 20 LBS 20 LBS
Mud, sand, snow 15 LBS 15 LBS