I have a 1990 f250 7.3 non turbo. When i got it i was told it had the c6. Tranny went out they said it was 850 to rebuild and upgrade, cool right thats nothing for a tranny.i get to the shop and they tell me its a e40d. It does have an overdrive button and the guy said thats c6 dont so the cost of a e40d is like 2200. Any opinions, i guess i could have been mis informed but before it went out it had trouble shifting from 1 to 2 then 2 to 3 then it was smooth so i figured 3 speeds=c6? Idk confused and pissed about a 1400 dollar differance.

 

The C6 is three speeds and has no overdrive.
The E4OD has 4 gears including an Overdrive. It is also electronically controlled.

What you have in the truck may not be what it originally came with, so the only way to be sure is to look at the transmission itself.

Take a look at this page, it includes pictures:
Articles - Custom Built and High Performance Transmissions

 

Does anything happen when you press the overdrive button while driving over 35 to 40 mph. If it has an overdrive button it originally came with an e40d. The factory pan for an E4od says "Metric" on it. IDK if the c6 pan does or not.

 

Nope, the C6 doesn't say anything on the pan

 

most important to diagnose the tranny first. several sensors give vital info to PCM to control shifts, there is a rpm sensor $75 speed sensor $18 and TPS $55 dirty connections will cause intermittent shift symptoms..

 

The truck is at the shop but i dont know about the overdrive. K do know if i push it the little orange light would come kn to jndicate it was on but i image that doesnt mean much?. I dont think it says matric but the pan also doesnt have grooves like most pictures of c6 transmission pans do. I do know its a L pan thats about it but i cant see it unfortentuly

 

I really dont think my pan does say anything nut o cant look at the moment

 

Nothing would work on the truck except reverse. For almost 4 years the was a shutter/studder from 1 to 2nd then for about 1.5 years from 2nd to 3. Although the truck has under 160

The shop said they would get to it monday, maybe they will call and say kt is a c6

 

when the light is on the OD is off... the shudder could be caused by bad speed sensor...