Talk to me about the C6 trans!

[89dieselbko]

Ok so i have never had a C6 trans. couple AODs, an E4OD, few mazda 5 speeds (m5od-r2 or w/e) all gassers trans and know what they are like when working. I also know what my zf5 in the bronco works like when its working...

My 95 F350 crew cab, has a 351W and a C6 trans. i know its a 3 speed, no OD, thats stupid stuff. What i dont know, is how they shift and run?

My truck seems to be in third gear at 30-35 MPH, and gutless up to about 60, at 60 if i punch the throttle you could almost swear the truck will ride a wheelie down the road.

Now my curiosity... say im at 50 MPH, the trans wont shift down, no matter the throttle (i assume the RPMs would be to high anyways, 3.55 gears, 235 tires) But at 40-45 it will shift down... is this *proper* or do i have some issues? i havent tried to manually shift it in fear of over revving my 176k mile engine (no signs of rebuild, but you never know)

If the trans should be shifting... i understand its vacuum controlled, could i have a vacuum leak? or maybe the vacuum sensor thing? i have the kick down adjusted properly

 

[Hydro-idi]

Sounds normal to me. My c6 shifts about the same as to what you are describing with yours.

 

[89dieselbko]

bleh, thats ******. My current drive to work is up and down hills and i always get stuck doing 45-50 on them in a 65 zones. To be honest i was kind of hoping for a *your *insert part* isnt working right

Thanks for the information tho! Guess this C6 is destined for the 300 i6 in my 82 F150 plow truck!

 

[Wyreth]

If you had a vacuum leak, it wouldn't want to shift until later. Vacuum goes away the more throttle you give an engine. So little or no vacuum tells the modulator the throttle is wide open. You could try getting a different modulator. That will change your shift points depending on which one you get. (I don't remember the color chart, other than I believe black is diesel) Or you can get an adjustable one, and minorly adjust the points to where you feel best. At WOT the internal "hard" shift points run approx 35 for 1-2, and 50 for 2-3. These are not adjustable without machining or replacing the valve body, and it will not kick down over those speeds.

 

[FORDF250HDXLT]

the trans is working correctly,but engine timing sounds drastically retarded.

 

[89dieselbko]

it could be, it stumbles sometimes, im to lazy to mess with it to much. Been working on finishing up my 7.3 short block assembly when im home, and trying to find the money to get my heads rebuilt lol.

Thanks for the information tho, i called a few yards and left msgs for tomorrow morning, seeing if anyone has a zf/mazda 5speed i can swap into the truck over a weekend coming up. Dont care for the shift points, and im far to lazy to bother with machining of anything on this trans, i suppose ill just yank it sooner rather then later as planned lol.

 

[IDIDieselJohn]

Yep, that sounds like a normal healthy, quick, firm shifting C6!

 

[idi_econoline]

Yepyep, sounds like the 351W/C6 in my old blue F250, 89dieselbko. Sadly, the C-6 was the only trouble-free part on that truck. She broke faster than I could fix her.