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Turbo-Hydramatic 425/325/325-4L
Ypsilanti Automotive Heritage Museum May 2015 057 (1965-78 THM 425 transmission).jpg
A THM 425 transmission, produced between 1965 and 1978, at the Ypsilanti Automotive Heritage Museum
Manufacturer General Motors
Production 1966–1985
Body and chassis
Class 3-speed longitudinal automatic transmission
Related Turbo-Hydramatic 125
Turbo-Hydramatic 180
Successor 4T60

Turbo-Hydramatic 425 (and later 325) was an automatic transmission developed and produced by General Motors. The THM425 was a derivative of the THM400; most parts directly interchange and some others will interchange with minor modifications. The internal parts spin the opposite direction in the THM425; the helical angle of the planetary gears is "reversed" and the one-way clutches freewheel in the opposite direction, for example. The THM425 was developed for the 1966 Oldsmobile Toronado and the 1967 Cadillac Eldorado. A lighter-duty transmission known as the THM325 replaced the THM425 in both car lines after the 1978 model year. 1979 and later longitudinal engine front-wheel drive vehicles used the THM325. The THM325 became the THM325-4L with an overdrive added in 1982, but all vehicles using this transmission switched to more-conventional transverse engine mounting in 1986.

A THM 325 transmission, produced between 1978 and 1985


See also[edit]

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Turbo-Hydramatic_425 — Please support Wikipedia.
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147 videos foundNext > 

IMG 0781

Under the hood.MP4

Under the hood of the 1968 Oldsmobile Toronado. This is the original 455 engine and original turbo-hydramatic 425 automatic transmission (numbers match).

1977 Cadillac Eldorado Coupe

Price: $9950 Stock Number: 10733 Engine: 425 CID V-8, 7.0L Transmission: "425 Series" Turbo Hydra-Matic Mileage: 68437 Believed Original Miles VIN: ...

GM Turbo Hydromatic 400 Lesson (TH-400)

2/15/2011 - This is the transmission that is in my 1974 Cadillac Coupe deVille. Listen carefully, this is very informative.

1967 Cadillac Eldorado walk around start up & test drive before restoration

The Caddy has 60k original actual miles. Before start up I drained the fuel tank purged the fuel system with new fuel, lubricated the top of engine rebuilt the ...

Lot S88 1969 Chevrolet Yenko Chevelle 427 425 HP Auto

Don Yenko gave the 1969 Chevelle the same loving attention he lavished on the Camaro, but in smaller numbers, building 99 copies against 201 Super ...

1976 Cadillac Eldorado Convertible For Sale

THIS VEHICLE IS FOR SALE. Call us - 636-600-4600 Visit our Showroom - 2340 Cassens Dr. St. Louis MO 63026 http://www.motoexotica.com/ WE BUY CARS!

1975 Cadillac Eldorado Convertible Gateway Classic Cars Chicago #810

810 For sale in our Chicago showroom is a beautiful 1975 Cadillac Eldorado Convertible. By 1975 most auto manufacturers were phasing out convertibles and ...

1956 Cadillac Series 62 Coupe For Sale

THIS VEHICLE IS FOR SALE. Click "Show More" for more information! Call us - 636-600-4600 Visit our Showroom - 2340 Cassens Dr. St. Louis MO 63026 ...

Turbo Hydra-Matic 400 Transmission shift modification

In this vid the process of removing the spring from under the front accumulator piston is demonstrated. This modification yields a firmer second to third shift.

147 videos foundNext > 

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