Aluminum Transmission Pan

In the search for cooler transmission opering temperatures, a PML Transmission Pan was fitted. The sand cast transmission pan offers two additional quarts of capacity and raised cooling fins, as well as being substantially stronger than the stock pan. It is also contoured to allow for the cross over section of the stock exhaust system.

As it is out of view, an unfinished transmission pan was chosen, although they are available in black powder coat and polished finishes. The pan comes with hex head bolts and includes a magnetic drain plug, but does not include a gasket. However, a new transmission filter was put in as the cover was already off and a new gasket is included with the filter.

Removing the stock pan is relatively easy, and contrary to what was previously thought, can be removed with the exhaust in place, although it is very tight. The bracket for the shifter cable needs to be bent all the way over away from the pan to allow the pan to be removed.

Installing the new pan with the exhaust in place initially looked as though it couldn't be done. So it was decided to disconnect the exhaust where it connects to the header to allow for sufficient clearance. Unfortunately, one nut would not come loose, and risked breaking the stud. By careful use of a pry bar, the exhaust was moved down enough to slide the new transmission pan in place. It should be noted that ideally the exhaust should be dropped clear to do this.

The hex head bolts were all tightened to 12 ft/lbs and the drain plug to 20 ft/lbs, the shifter cable bracket was bent back over towards the pan, and approximately 8 quarts of Royal Purple ATF was added.

The exhaust section that crosses under the transmission pan was also covered with header wrap to reduce the heating effect of the exhaust.

The transmission now runs at around 175F on the highway with an outside air temperature of around 90F, and reaches 195-200F with the torque convertor out of stall (generating most heat) running against a head wind at 70 mph. Engine temperature stayed around 195-200F.

Update: On long trips the transmission still gets hot (225-230F) when out of stall for a long time. When stalled it runs cool.

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