C6 tranny

[Hydro-idi]

I used to get around 16 mpg on the highway in my idi with C6. That was going around 65 mpg highway with 3:55 gears.
Put 3.08’s in it and sold rig shortly after to father in law who regularly gets around 18-19 mpg. Good transmission.

 

[Thewespaul]

I am pleasantly surprised at such good mileage with a C6. perhaps with good tuning of IP I can do this also. I have a 6.9 with C^ and 3.55 rear end. and 4X4. I am by no means an expert but the consensus on this forum does not bode well for that high of mpg with the c6. I have considered an E4OD. I have one that needs rebuilt but considered it cheaper and/or easier/less time consuming to add the gear vendors and swap in my 410 rear end.

I have a spare e40d and torque converter here at my shop

 

[Hydro-idi]

I have a spare e40d and torque converter here at my shop

Throw that thing in the dumpster

 

[Thewespaul]

Throw that thing in the dumpster

Been trying to give it away for a year

 

[Runningaford]

I am pleasantly surprised at such good mileage with a C6. perhaps with good tuning of IP I can do this also. I have a 6.9 with C^ and 3.55 rear end. and 4X4. I am by no means an expert but the consensus on this forum does not bode well for that high of mpg with the c6. I have considered an E4OD. I have one that needs rebuilt but considered it cheaper and/or easier/less time consuming to add the gear vendors and swap in my 410 rear end.

The rear end was a replacement, I'm not sure of gearing; my guess it would be high. The mileage could easily be explained by that. I did see it first hand. The last road trip was from Austin, to North Idaho(2100 miles) around 16 years ago, and on that trip, the average was 18mpg. I think at the time, the 7.3 that's in it, had around 50k miles since new.

 

[typ4]

Muleman, ford stopped using typeF in 1978 or so. FYI, It wont hurt anything just letting you know.

 

[Hydro-idi]

Muleman, ford stopped using typeF in 1978 or so. FYI, It wont hurt anything just letting you know.

Good point. My transmission rebuilder recommended using dextron III/Mercon in it after he rebuilt my C6, and said it was a much better fluid to use even in transmissions that require type F.
Also looking at the original trans dipstick in my 87 idi before I sold it, it said dextron III/mercon right on the stick.

 

[typ4]

As did my 79.

 

[fjkontur]

had c6 rebuilt with extra clutch and shift kit . its behind my 87 4x4 hauls 13 big ass hay bails with no problem. sh-- can the e40d .