The International T-6 series included gasoline and diesel crawler tractors built by the International Harvester company from 1940 to 1969.

Model historyEdit

For Company history, see International Harvester.

The International T-6 and TD-6 were new small crawlers from International, following the styling theme introduced earlier on the TD-18. The original models of the entire crawler line used hood side panels with a horizontal silver bar on the side panels matching horizontal silver bars on the grille. Somewhere around 1950 the side panels were dropped (or made optional) and the grille was painted all red. The T-6 was larger and more powerful than the unstyled T-20 it replaced, and had a 5-speed instead of 3-speed transmission. The T-6 shared the 248 ci 4-cylinder gasoline engine and 5-speed transmission of the McCormick-Deering Farmall M and W-6. The T-6 competed with the Allis-Chalmers M, Caterpillar R-2, and Cletrac AG-4. All of these tractors were rated at 3-4 plow. The T-6 was the same physical size as the Caterpillar R-2, but heavier and more powerful, with a 248 ci engine vs. Caterpillar’s 221 ci.

The TD-6 diesel was identical to the gasoline-powered T-6 except for the engine. The 248 ci 4-cylinder diesel was very similar in basic design to the gasoline version, but strengthened to withstand the stresses of operation on diesel. Like all International diesels of the time, it started on gasoline. In 1940 the TD-6 had a larger engine than the Caterpillar D-2 (248 ci vs. 221 ci) and developed somewhat more power. The TD-6 was a little less powerful than the Cletrac AD. In mid-1947 Caterpillar enlarged the engine of the D-2 to 251ci, making the D-2 slightly more powerful than the International TD-6. In 1951 International revised the TD-6 by increasing the compression ratio from 14.2 to 16.8. In Nebraska test no. 482 the revised tractor developed 38 belt and 32 drawbar horsepower. The TD-6 was now more powerful than the Cat D-2. The original T-6 and the TD-6 diesel were in production from 1940-56. In 1956 International came out with the still higher powered T-6 Series 61 and TD-6 series 61.

The new Series 61 was the first major change to the T-6/TD-6 in 16 years. New styling amounted to a grille made up of thin vertical bars only, vaguely resembling the grille of the flagship TD-24. The 4-cylinder gasoline and diesel engines were increased to 264 ci displacement. They were basically the engines of the McCormick-Deering Farmall 400 and International 400 wheel tractors with engine speed increased by 100 rpm. Each new model weighed several hundred pounds more than the corresponding old model and gained 11 belt hp. 1959 was the last year for the 4-cylinder Internationals. In 1960 they were replaced with the 6-cylinder Series 62.

The external appearance of the new models was nearly unchanged but the tractors were lengthened 5" to make room for the longer 6-cylinder engine. The engine of the International T-6 Series 62 was the same 263 ci gasoline model as in the McCormick-Deering Farmall 560 wheel tractor, but with governed rpm reduced to 1,550. The new T-6 was still basically a farm crawler, with its 5-speed gear-drive transmission. The only other gasoline crawlers of similar size in 1959 were the Case 610 and the Oliver OC-9, both industrial models with 4-speed partial power-shift torque-converter transmissions. In 1962 John Deere introduced its 2010C, with a small high-speed 4-cylinder engine and dual-range 8-speed transmission. In 1966 Case replaced the 610 with the new 450, using a Case ohv 4-cylinder engine instead of the previous Continental L-head six. At the same time, John Deere replaced the 2010C with the stronger JD450 powered by a new 183 ci 4-cylinder.

The TD-6 Series 62 was the same as the T-6 described above except that it used the 281 ci 6-cylinder diesel engine borrowed from the 560 Diesel wheel tractor. The competitive situation for the TD-6 was basically the same as for the T-6. In 1959 the only competition for it came from the Case 610 and Oliver OC-9. These were joined by the John Deere 2010C in 1962 and the Case 450 and John Deere JD450 in 1966. In 1965 International added the higher-powered Agricultural Crawler with the ended speeded up from 1550 to 1800 rpm, increasing the hp output by a small amount. International soldiered on through 1969 with the T-6 and the diesel TD-6, but diminishing sales caused them to be replaced by the made-in-Germany industrial/construction-oriented International T-7C and TD-7C.

Timeline Edit

  • 1940 - International T-6 and TD-6 replaced the McCormick-Deering T-20
  • 1951 - TD-6 compression ratio increased for slightly more power
  • 1956 - T-6 and TD-6 Series 61 with larger engines replaced the original T-6 and TD-6
  • 1959 - 6-cylinder T-6 and TD-6 Series 62 replaced Series 61
  • 1969 - 4-cylinder T-7C and TD-7C replaced the T-6 and TD-6 models

Model lineupEdit

See the following articles for detailed specifications

Factory locations Edit

Serial Numbers Information Edit

Year Serial no. run
Serial no. run
Number Built Notes
1940 T6 or TD6-501 4434 3934 Serial range includes T-6 and TD-6
1941 4435 8189 3755 Numbers built calculated
1942 8190 9296 1107
1943 9297 9580 284
1944 9581 10827 1247
1945 10828 12055 1228
1946 12056 14515 2460
1947 14516 17348 2833
1948 17349 21144 3796
1949 21145 24859 3715
1950 24860 27535 2676
1951 27536 31055 3520
1952 31056 33156 2101
1953 33157 35745 2589
1954 35746 37469 1724
1955 37470 38705 1236
1956 38706 38950 245
Total built to date 38450[2]
1956 T61 or TD61-38951 39816 866 Includes T-6 and TD-6 Series 61
1957 39817 40821 1005
1958 40822 41447 626
1959 41448
Total built to date 2500[2]
1959 T62 or TD62-501 1059 559 Includes T-6 and TD-6 Series 62
1960 1060 1629 570
1961 1630 2055 426
1962 2056 2403 348
1963 2404 2757 354
1964 2758 3176 419
1965 3177 3630 454
1966 3631 3990 360
1967 3991 4220 230
1968 4221 4423 203
1969 4424
Total built 3920[2]

Preservation Edit

No information on any individual examples of these tractors in preservation is currently available on here.

Do you know of any examples to list ? Yes I own a 1967 year diesel international in extremely good shape TD-6 and operational you can contact me at if you want pictures or additional information

Gallery Edit

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See also Edit

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)
  • Museums - includes museums featuring tractors (please add missing ones)

References / Sources Edit

  • 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. 2.0 2.1 2.2 Klancher, Lee, International Harvester Photographic History, Motorbooks International, Osceola, Wisconsin, 1996

External Links Edit

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