In my brother-in-law's 1994 F-150 XL there sits a 4.9 and an automatic tranny that has the L shaped pan (like the C6), but it has the button to turn off the overdrive on the gearshift. Now from what I understand, the C6 is a 3 speed. Any explinations here?

 

I would say it's an E4OD trans. If you go to my web site below you will find a page with trans. pan ID photos and give it a look. You'll see the C6 and E4OD to compare.