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GM Turbo 400 Deep
    GM Turbo 400 Deep
    Purchase GM Turbo 400 Deep
    • GM Turbo 400 Deep
      Part Number 9683

    • Pan includes magnetic drain plug and mounting hardware.
      Price varies with finish. SEE PRODUCT INFO.


    • OPTIONAL: add machining of a 1/8 NPT hole for an aftermarket temperature sending unit:

    Volume: 2 quarts over stock "car" type pan

    Dimensions: Click here for dimensions. Fin height about 0.220 inches.

    Number of Bolts: 13


    • Thick wall construction for strength
    • Gasket flange machined flat for a secure seal to the transmission housing
    • Finned for heat dissipation
    • Top quality sand cast aluminum
    • Drain and magnetic drain plug for easy servicing

    The transmission was first available in 1964.

    This pan has the same capacity as the stock TH400 "truck" pan. It is slightly larger because of the cooling fins on the bottom of the PML pan.

    PML also makes a stock capacity version of this pan, PML part number 9591.

    Two of these parts are on SPECIAL: SPECIAL #430 in as cast finish and SPECIAL #431 in polish finish

    The PML deep transmission pan fits many cars and trucks with the GM TH 400 transmission. This transmission is found in GMC and Chevy vehicles. For example:

    • 1970-76 models of Corvette, Chevy, Cadillac, Olds, Buick
    • Blazer (2WD and 4WD)
    • Hummer H1, 1991 and 1992
    • Jaguar (this pan has been installed on a 1991 XJS)
    • Jeep
    • K1500, K2500, K3500 (2WD and 4WD)
    • Ferrari

    Always check your vehicle to verify transmission and clearance. This PML pan fits the Turbo 400 transmission. It is larger than stock so make sure to check for clearance for a larger pan.

    If your stock pan has a dipstick receiver on the side of the pan, a PML Turbo 400 is not compatible with your vehicle.

    The TH400 transmission is called Super Turbine 400 or Turbo 400 in the racing field and is formally called THM400 for Turbo-Hydra-matic 400. It first appeared in cars in 1964 and continued in production in the 1980s. In 1980s GM changed the name to 3L80.

    No pictures of installations available.

    Included with PML Transmission Pan

    PML Th400 deep transmission pan package  Click on image to view larger.

    PML includes a new mounting hardware with each pan. The flange of the PML pan is much thicker than on the stock pan so the stock bolts would not be long enough.

    A magnetic drain plug is also included with the hardware for each pan. The magnet on the end of the drain plug can capture small bits of metal in the fluid.

    Inside of Pan

     Inside of this PML pan. Click on image to view larger.

    Drain hole is the botton the pan. Circular features on the bottom are supports for the filter.

    Optional Temperature Sending Unit Machining

    Optionally, PML can drill and tap a 1/8 NPT hole for a temperature sending unit. This would be for an aftermarket temperature gage. There is a custom machining charge.

    There are three locations on this pan that can be machined for a temperature sending unit. The bosses (thick areas) on the inside of the pan are located on:

    • driver side
    • passenger side
    • rear of the pan near the drain hole

    Select the option before adding pan to cart. A plug for the hole is included.

    The standard size is 1/8 NPT. Check your aftermarket gage to verify the thread specifications for the sending unit before ordering. Call or email if you need a different size.

    Filter, Gasket, and Tube

    Note: Installer must use the correct filter, intake tube and bolt/spacer kit for the vehicle configuration. PML is not responsible for any damage or injury.

    GM made at least two different pans for the Turbo 400 transmission.

    • One is called the shallow or 2WD or car stock pan and the GM part number is 8679995
    • One is called the deep or or 4WD or truck stock pan and the GM part number is 8679994

    The OEM pans had different intake tubes and bolt/sleeve kits. They used the same filter and gasket.

    For the filter, this pan is designed to work with the regular OEM filter. It is some times called the flat filter. This pan will not work with the side mount filter.

    For the gasket, PML recommends a cork or cork composite gasket. A paper for felt type gasket should also work. A customer recommended Mr. Gasket 8691, which is a cork composite gasket.

    For the intake tube pipe for the deep pan is GM Part Number 8629526. Intake tube pipe for the shallow pan is GM Part Number 8626886. There are different bolt/sleeve kits for each tube.

    This PML deep GM Turbo 400 pan should work with the stock deep pan tube and associated bolt/sleeve kit.

    Pictures of a gasket and filter for the GM TH400 transmission:
    GM Turbo 400 gasket and filter GM Turbo 400 gasket and filter   cork gasket thickness, Turbo 400 cork gasket thickness
    Click on image to view larger.

    Early Valve Body

    The early TH400 valve body uses a side mount filter. This "old style" filter could hit the internal boss. One customer with the early valve body, ground off the boss. Another customer drilled a hole in the valve body to hold the "new style" filter in place on his old valve body. He had switched to the new style filter before getting a PML pan. He found the old style filter to be a "bad design" since it kept sucking air.

    PML Transmission Pan Compared to Stock

    PML Transmission Pan Part Numbers 9683 and 9591 compared to stock   PML Transmission Pan Part Number 9683, compared to stock, top view
    Click on image to view larger in a new tab or window.


    In January 2008, PML moved the drain plug to bottom and temp sensor boss to driver's side. In 2017, we made the boss on the driver's side internal to the pan.

    These updates allow four wheel drive vehicles, such as Blazers, K1500, K2500, and K3500 to avoid drive shaft interference with the PML pan.

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