The DI
The DI was made from 1935 to 1941, even though 100 were made, 13 were scrapped or rebuilt into different serial numbers. So 87 or less still exsist today.
The DI is the tractor that started this idea for a web site. My grandfather has DI serial number 140337. You can learn more about his DI by clicking HERE.

The DI to the left is definitely NOT my grandpa's tractor! Right now, his is a rusty piece of junk!

You can click the picture to enlarge.


See more pictures of DIs, here.
See the special maintenance needs of your DI, here.
See a listing of the DI serial numbers, here.

Interesting tidbits of information for the DI-
Even though the DI was made into 1941, it was never styled!!!!

On August 28, 1935... It was decided that the Model DI was to be painted "Highway Yellow".

On December 9, 1936... The First Model D Industrial with production improvements was manufactured; serial no. 131266.


The DI only had a few minor differences from the agricultural version...
Compare the D and DI
Here is a picture to help with the major external differences. Number key is below.
  1. Turning brakes and a lever type handle to lock the brakes. Also with normal D parking brake. Some unstyled agricultural Ds had wheel brakes. Not many!
  2. Heavier and differently shaped drawbar (shaped like "Y" instead of flat)
  3. Padded, more comfortable seat, instead of steel pan
List of all major differences
  • Heavier rear axle housings
  • Heavier rear wheels with brake drums cast into the rear wheels
  • Heavier and differently shaped drawbar
  • Turning brakes and a lever type handle to lock the brakes. Also with normal D parking brake. Some unstyled agricultural Ds had wheel brakes. Not many!
  • Padded, more comfortable seat
  • Different speed final drive sprockets- usually faster than the Ag versions, option of very slow for more pulling power
  • I have seen pictures of DIs with extended controls-clutch, throttle. I don't know if every DI had these. Can anyone help? Usually seen with the Side Seat Assembly (see below)
Tires and wheels avaliable for the DI...
  • Regular-(rear) 12.75-28, (front)7.50-18
  • Or Dual (rear) 12.75-28
  • Or (rear) 13.50-28
  • Or (rear) 9.75-24 "balloon", also Dual
  • Or (front) 6.00-12 "balloon"
What to choose? Options, Options, Options!!!!
  • Cab- Part No. AD1511R See a few pictures of cabs...DIpic8, DIpic10, DIpic11
  • Dual Power Control-basically a two PTO setup, used with the CaterpillarTrailer Patrol (a grader)- Part No. AD2312R
  • Side Seat Assembly- used with the Dual Power Control- Part No. AD1272R (basically, it turned the seat sideways allowing the operator to easily see the grader and operate the tractor at the same time.)
Specifications of the DI-(taken from various sources). Most info is for the model D, but will be the same (or vary only slightly) for the DI. Speeds are for the DI.

Capacity in Plows= 3 or 4 (14")
Tranmission Speeds, 1935-1936(MPH)
1= 4
2= 5 1/5
3= 7 7/10
Reverse= 2 9/10

Transmission Speeds, 1937-1941(MPH)
1= 3 3/5
2= 5 3/10
3= 7 1/2
Reverse= 2 2/5

Clyinders= 2
Bore= 6 3/4 inches
Stroke= 7 inches
RPM= 900
Fuel= Kerosene
Fuel Tank Capacity (U.S. Gallons)
Main= 25
Auxiliary (otherwise known as the Gasoline or "starting" tank)= 1 1/2
Cooling Capacity= 10 (U.S. Gallons)
Standard Wheel Size (inches)
Front= 7.50x18
Rear= 12.75x28
Dimensions (inches)
Length= 130
Width=66 1/2
Height= 61 1/4 1/4
Weight= 5269 pounds