I just bought this 1994 F-150 with a 302 motor and a M5OD-R2 tranny. The tranny will drop 1.5-2 quarts of fluid in 100 miles. Both the input and output shafts are not leaking at all. So I did some research and found that a common problem is with three rubber shift rail plugs on the top near the rear. I said to myself, "That's the darn problem, there has to be a big hole for this thing to drop that much fluid that quick!". I went and bought the things for $12 apiece from ford.

Last night I tore into it, and removed the top of the gearbox. All three plugs where there and intact, but loose. I replaced them and used a little RTV too. Then I cleaned the gearbox cover and mating surface. These use a rubber oring type seal. I decided to go with the RTV here as well.

Upon inspection of the shifter, the bushings were cracked, an there was a lot of fluid around it . I think this is where the majority of the leak was. So now, back to Ford to buy some overpriced rubber and plastic. I'll post part numbers and prices shortly.

Wait, I also was turned onto this site for tranny parts:

Catalogs Motive Gear

Just download the catalog for light duty transmissions. It has diagrahms and all. I can't wait on an order (unless I have too), I'll let ya'll know what Ford says.

 

Ok, so I went to the dealership, and the round ring that has three holes for the torx bolt complete with rubber gasket set me back $49.99. One of the plastic shifter bushing without the wave spring was ~$12. Not the worst day, but certainly not the best. If I hadn't already bought all the parts I would look into that $200 Hurst shifter that I hear tell of.

 

A lot of that M5R2 stuff you can find for cheap on eBay.

 

It should be a lot cheaper than the prices I mentioned above by the looks of it. That's good to know. I think I stopped the leaks, now to address this loud PS pump and sticky throw-out bearing.