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International TD-9 1951

The original International T-9 gasoline and TD-9 diesel crawler tractors were built by the International Harvester company from 1940 to 1956.

Model history

For Company history, see International Harvester.

The International T-9 and TD-9 replaced the unstyled McCormick-Deering T-35 and TD-35. The new models continued the styling theme introduced in 1938 on the big TD-18 crawler. All of the new International crawlers had engine side screens with horizontal silver stripes, matching three silver grille bars dividing sections of red cross bars. The T-9 looked almost identical to the T-6, except scaled up. The main visual clue from a distance is the presence of two top track idlers on the T-9/TD-9 vs. one on the T-6/TD-6. Instead of the 6-cylinder gasoline engine of the T-35, the T-9 used a new 335 ci 4-cylinder gasoline engine, governed at 1400 rpm, with a 5-speed transmission. This engine and transmission were shared by the McCormick-Deering W-9/WD-9 series wheel tractors. In 1940 the T-9 competed with the Caterpillar R-4 and Cletrac BG-6 but was more powerful than both. International dropped the T-9 in 1956.

The TD-9 used a diesel version of the 335 ci 4-cylinder of the T-9 instead of the 414 ci diesel of the TD-35. When it introduced the TD-9, International was trying to compete with the Caterpillar D-4 and so it designed a very similar tractor. Both tractors were the same size and powered by 4-cylinder diesel engines running at 1,400 rpm with 5-speed transmissions. Caterpillar used its pony motor starting system while the International started on gasoline and then switched to diesel. The basic International was crank started with an electric starter optional. In 1940 the TD-9 had a slightly larger engine than the D-4, 335 ci vs. 312 ci, and developed slightly more power, 44 vs. 40 belt hp. The only other tractor in this class was the Cletrac BD-6, which developed 46 belt hp from a 298 ci 6-cylinder Hercules diesel running at 1,400 rpm. The Cletrac had only a 3-speed transmission. In 1947 Allis-Chalmers brought out its new HD-5, the most powerful tractor to date in this class with 48 belt hp. Caterpillar increased the engine size of the D-4 to 350 ci, boosting it to 48 belt hp also. International responded in 1951 with a small upgrade to the TD-9 that developed 47 belt hp. About the same time the tractor lost its engine side screens and silver bars in the grille. In 1955 Caterpillar went to 59 hp, Oliver to 57 hp, and Allis-Chalmers to 61 hp. Clearly the TD-9 was falling behind its competition so, in 1956, International brought out the revised International TD-9 Series 91 .


  • 1940 - International T-9 and TD-9 replaced the McCormick-Deering T-35/TD-35
  • 1951 - TD-9 power increased slightly
  • 1956 - TD-9 Series 91 with larger engine replaced the original TD-9

Model lineup

See the following articles for detailed specifications

Factory locations

Serial Numbers Information

Year Serial no. run
Serial no. run
Number Built Notes
1940 TCB or TDCB501 2173 1673 Serial range includes T-9 and TD-9
1941 2174 4173 2000 Number built calculated
1942 4174 8663 4490 tcb7189t4n us7
1943 8664 11911 3248
1944 11912 18249 6338
1945 18250 23690 5441
1946 23691 26289 2599
1947 26290 29511 3222
1948 29512 32972 3461
1949 32973 36926 3954
1950 36927 40397 3471
1951 40398 44709 4312
1952 44710 47848 3139
1953 47849 52599 4751
1954 52600 56207 3608
1955 56208 58818 2611
1956 58819 60300 1482
Total built 59800[2]


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See also

Collection related info
  • Shows and Meets - events featuring tractors and other machinery
  • Clubs Listing - List of clubs including various tractor marques
  • Collections - list of private collections with tractors (add yours)
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References / Sources

  • Please supply some relevant references or sources for information for verification of data.
  1. Heartland Guides Division, Hot Line Antique Tractor Guide, Volume X, Heartland Communications Group, Inc., Fort Dodge, Iowa, 2010
  2. Klancher, Lee, International Harvester Photographic History, Motorbooks International, Osceola, Wisconsin, 1996

External Links

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