GM Turbo 400 Deep
Part Number 9683

Volume: 2 quarts over stock "car" type pan

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

Number of Bolts: 13

Benefits:

• 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

 
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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, gasket, 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 pan and the GM part number is 8679995
• One is called the deep or or 4WD or truck pan and the GM part number is 8679994

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

The intake tube pipe for the GM shallow/2WD/car pan is GM Part Number 8626886. The intake tube pipe for the GM deep/4WD/truck pan is GM Part Number 8629526.

This PML deep GM Turbo 400 pan should work with the GM deep/4WD/truck pan tube and bolt/sleeve kit.

This PML pan is designed to work with the OEM stock filter and gasket. The filter is some times called the flat filter. This pan will not work with the side mount filter. A cork, cork composite, paper or paper fibre/felt type gasket work best with a PML pan. A customer recommended cork composite Mr. Gasket 8691.

The AC Delco filter is part number TF231 and it usually comes with a fiber paper gasket. Pictures of a cork gasket and AC Delco TF231 filter for the GM TH400 transmission:
GM Turbo 400 gasket and filter   cork gasket thickness   Bottom of AC Delco filter   top of AC Delco filter   top of AC Delco filter
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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

 
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Revisions

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.