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The Cat D2

Series 3 & 5J and 4 & 5U

The D2 is one of the most well-known and most-admired of the classic Caterpillar Diesel tractors. Production of the J series began in 1938 and ran until 1947 when the redesigned U series continued the line until 1958 when the D2 ceased production. They were the smallest diesel-powered crawler tractors that Cat produced and are a whole lot of fun today. There were many changes and refinements made to the D2 over the years. Let's start with the series designations. The J series was first, 3Js are the "narrow gauge" tractors and the 5Js the "wide gauge", these prefixes designated the width of the tractor from the center of track to center of track, 3Js are 40" on center, 5Js are 50". The U series followed the same protocol, with the 4Us being narrow and 5Us being wide. The big difference in the U series was the new D311 engine and other refinements as a result. The table below has more on what changed between the J and U series tractors. You can find the series designation on the serial number plates which are aluminium plates located in two places, at the top rear left hand side of the engine block and at the top left hand side of the rear of the transmission case.

D2

D2

D2's were put to many uses and there were many factory variations. You could find D2's on farms, in orchards and vineyards, logging, and on construction sites. There were versions that were specifically created for these applications. They were versatile, durable, and economical to operate for any of the tasks they were asked to accomplish. They are popular with people that have an interest in classic machinery due to their relatively small size and they can be transported (In the USA) with a pickup and a double axle trailer. Let's not miss the fact that they are still handy and can be found working in the field to this day. The D2 has earned its well-regarded status many times over with its ability to work tirelessly, and continue to provide today many hours of enjoyment for their owners.

How to Tell the Difference - the basics

D2 J Series

D2 U Series

1938-1947

1947-1957

D3400 Diesel Engine

D311 Diesel Engine

28.8 D.H.P.at 1525 rpm

32 D.H.P, 38 from 1954

Weight 6,850 lbs.

Weight 6,870 lbs.

Main engine air cleaner

Main engine air cleaner

located at front right of bonnet

in front of operator at dash

D2

Except for the early J series tractors the starting engine exhaust surrounds the diesel air intake manifold for quicker starting. Early J series tractors also had straight steering clutch levers.

Below is a list of machines made by year, model and serial number.

Year

3J

5J

1938

1

2459

1

1259

1939

2460

4013

1260

2229

1940

4014

4952

2230

3549

1941

4953

6243

3550

5144

1942

6233

6789

5145

6153

1943

None

None

None

None

1944

6790

7019

6154

7000

1945

7020

7629

7001

7839

1946

7630

7800

7840

9269

1947

7900

8600

9270

10561

Year

4U

5U

1947

1

286

1

550

1948

287

1428

551

2199

1949

1429

2425

2200

4038

1950

2426

3750

4039

6403

1951

3751

4408

6404

8923

1952

4409

5584

8924

11285

1953

5585

6315

11286

13101

1954

6316

6864

13102

14700

1955

6865

7193

14701

15800

1956

7194

7385

15801

18200

1957

7386

7560

18201

18894

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