I have a 1984 E150 with a beloved l6-300 and automatic.
Two questions:
1.) how do I tell whether the trany is a C3, C4 or C5 or whatever (hint: no overdrive)? What's the difference here?

2.) what is the rearend gear ratio? I know that I could probably figure it out by spinning the driveshaft and counting the wheel as it spins around.

Regards,
Jeff

 

Here's the beauty of this site, you can find someone to answer or help answer your question. I have two pieces of information. 1) Crawl under your truck and look at the transmission fluid pan. If it is soley rectangular in shape with 11 bolts holding it in place, it's a C4 or C5. If it the pan has an extra corner in it with 13 bolts holding it in place you have a C3 (the C6 has 17 bolts). 2) Here's more info between the C4 and C5 thanks to "The Haynes Ford Automatic Transmission Overhaul Manual." p. 4-1.
"The C4 transmission is the earliest-design transmission covered by this manual. It was originally designed for small and intermediate cars and trucks equipped with six-cylinder and small V-8 engines. The C4 was introduced in 1964 and continued to be produced through 1982, when it was superseded by the C5 transmission.
The C3 transmission is essentially a light-duty version of the C4 transmission. It was used from 1974 through 1986 on smaller cars with four cylinder, V6 and small V8 engines.
The C5 transmission began production in 1981 and superseded the C4 in 1982. The C5 is fundamentally a modernized version of the C4 with a torque converter clutch to provide converter lock-up during cruising. The C5 transmission stopped production in 1986, when it was replaced by the AOD transmission."
My guess would be you have a C5, check your VIN number. I hope this helps you.