Transmission Leak / Pan replacement

The transmission is a Turbo Hydra-Matic 350 ( THM 350 ) which is commonly just called TH 350. It is a 3-speed Automatic Transmission ( 3 forward speeds + reverse ) produced by General Motors, first used in 1969 and prevalent in nearly all rear wheel drive vehicles through to 1984. My transmission was constantly leaking from the oil pan despite fitting a new gasket. The original oil pan is shown here ( was painted red few years back ).

General Motors for some inexplicable reason never fitted a drain plug, so removal is a fun affair! The method is to slacken the bolts and then remove them on one side to allow pan to tilt and drain into a large receptacle, whilst trying to avoid an oil shower - very messy.

This photo shows the pan removed, and the old filter still in place. This next image shows the new filter fitted and the gear select mechanism disconnected and hanging down ( a later blog will show the restoration of the entire gear select assembly )

I decided to replace the original transmission pan with a new polished aluminium unit which had the luxury of a drain plug fitted ( see pictures below )

As you can see, I don't take any chances when working under the vehicle ( supports all over the place ). Better to be safe than sorry I say.