Chevrolet Turbo Hydra-Matic 400

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The Turbo Hydra-Mastic 400 (TH400) three-speed transmission was developed by GM and first found its way into Chevrolets in 1965. First introduced in 1964 under the name "Turbo Hydra-Matic" in Cadillacs and "Super Turbine" in Buicks in 1964. The TH400 saw its first use in Chevelles as an option with the SS 396 series sport coupes and convertibles but was also optional on 1967 El Caminos with any one of the three 396-cid engines in 1967. The TH400 continued to be one of two optional automatic transmissions in the SS 396 series Chevelles until the 1969 model year when the Powerglide was dropped with the 396 engine with the SS 396 option (RPO Z25). The Powerglide continued to be used until 1973, just not with the SS 396 or SS 454 engines. Various TH400 transmissions were used dependent on the particular 396/454 engine they were used with. When you ordered a 1979-1972 Chevelle with a 'big-block' engine, the appropriate TH400 was automatically selected at the assembly plant and installed.

Interesting that no Chevelle with a 'small-block' engine was ever offered with the TH400 but the TH400 was used with 'small-block' Corvettes and full-size Chevrolets beginning in 1968.

Only those documented via build sheets or other paperwork is listed here and other models of Chevrolets may use the same transmission tag codes. The TH400 was only available when a 396/402/454 engine was ordered. The 2-speed Powerglide was still an available automatic transmission option in 1967 and 1968 but was dropped for the 1969 model year behind 396/402/454 engines. There may be others but they haven't surfaced to date.

Some Chevrolet applications are shown here with the tag code, engine, and Chevrolet model.

Chevelle Examples

1967

521 ~ June 5, 1967 (521 days from January 1, 1966)
CC - 396 325hp
67 ~ 1967 model year
15486 ~ Transmission serial number

1968

538 ~ June 21, 1968 (538th day from January 1, 1967)
CC ~ 396 325hp
68 ~ 1968 model year
60372 ~ Transmission serial number

1969

205 ~ July 23, 1968 (205th day from January 1, 1968 [leap year[)
CE ~ 396/402 350hp
69 ~ 1969 model year
1161 ~ Transmission serial number

395 ~ January 29, 1969 (395th day from January 1, 1968 - leap year)
CX ~ 396/402 & 427 (375hp)
69 ~ 1969
2147 ~ Transmission serial number

1970

304 ~ October 31, 1969 (304th day from Jan 1, 1969)
70 ~ 1970
CF ~ 402 (350hp)
8569 ~ Transmission serial number

300 ~ October 27, 1969 (300th day from Jan 1, 1969)
70 ~ 1970
CS ~ 454 (360hp)
x244 ~ Transmission serial number

413 ~ February 17, 1970 (413th day from Jan 1, 1969)
70 ~ 1970
CY ~ 396/402 & 454 high shift point (375hp & 450hp)
1928 ~ Transmission serial number

1971

463 ~ April 8, 1971 (463rd day from Jan 1, 1970)
71 ~ 1971
CD ~ 402 (300hp)
12894 ~ Transmission serial number

218 ~ August 6, 1970 (218th day from Jan 1, 1970)
71 ~ 1971
CF ~ 454 (365hp)
1927 ~ Transmission serial number

1972

517 ~ June 1, 1972 (517th day from Jan 1, 1971)
72 ~ 1972
CD ~ 402 (240hp)
18002 ~ Transmission serial number

Courtesy Bill Hall
203 ~ July 22, 1971 (203rd day from Jan 1, 1971)
72 ~ 1972
CF ~ 454 (270hp)
1535 ~ Transmission serial number

Corvette Examples

1970

 
545 ~ June 29, 1970 (545th day from Jan 1, 1969)
70 ~ 1970
CK ~ 350 (300hp)
4163 ~ Transmission serial number

1977

378 ~January 12, 1977 (378th day from Jan 1, 1976)
77 ~ 1977
CB ~ 350 (200hp)
1905 ~ Transmission serial number

Partial Vehicle Identification Number Location

Driver side of case just above oil pan rail

Transmission oil pan

Early 1967 El Camino TH400 oil pans had a unique heel mark, a bump, and 3 dimples.

According to a Chevrolet Service News Bulletin around July of 1967 saw a change in the TH400 oil pan; the heel mark, bump, and 1 of the dimples was gone.

Mac's Registries

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