C6 vs 4 speed
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C6 vs 4 speed
Alright so I'm working along on my truck, and I've got the engine tore down and trans out. I was wondering the difference between a C6 and a standard 4 speed, such as which is better? It currently has a 4 speed, but I was wondering if the C6 had any advantage over the 4. Thanks
Hotshot
Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
The C6 shifts faster than the manual four speeds. I had an 84 F250 that I built a pretty beefy 300 for, and it was originally a four speed truck. That was completely worn out, so I built a nice C6 to go along, and the truck was actually much harder accelerating. I don't have numbers specifically for mileage, but it seemed to go down a little.
Fleet Owner
Joined: Dec 2009
Posts: 20,678
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From: NorCal
Manual trans are more efficient because less energy is lost through heat and torque converter slip/stall.
An auto trans works against itself while idling in gear at a stop. No such loss with a manual trans in neutral since it is mechanically disconnected.
An auto trans works against itself while idling in gear at a stop. No such loss with a manual trans in neutral since it is mechanically disconnected.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
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From: Creedmoor, North Carolina
They spend more time in hi gear than any other place. I say Damn a full grown Ford truck that can't shift it's own gears. I know HIO likes his 5 speed and he's welcome to it. The C6 is a top of the line 50 year old design.
Do you want to shift the gears or let the truck do it? My understanding Ford no longer offers manual shift transmissions in trucks. With the exception of between your ears, there's no real reason to go in that direction.
My 2
John
Do you want to shift the gears or let the truck do it? My understanding Ford no longer offers manual shift transmissions in trucks. With the exception of between your ears, there's no real reason to go in that direction.
My 2
John
Lead Driver
Joined: Apr 2011
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From: El Dorado, Arkansas
A 4-spd manual transmission will have a wider gear spread than the C-6 and, depending on what manual you have, 1st gear would be lower (to much lower) than the 1st gear ratio of the C-6. C-6 1st gear ratio is 2.46:1.
No matter what transmission you have, manual or automatic, if it isn't overdriven, it will be 1:1 in high gear. This being the case, it isn't going to lower the engine RPMs at cruising speed if it isn't an overdrive transmission.
It's just a decision on whether you want to shift gears or not as to which way you go with the transmission.
My truck has a C-4 automatic. It's the first vehicle in nearly 30 years I've had that doesn't have a standard. While I like a manual, 30 years of shifting gears every day tends to get old. It's nice to get in a vehicle that doesn't have to be shifted for a change.
No matter what transmission you have, manual or automatic, if it isn't overdriven, it will be 1:1 in high gear. This being the case, it isn't going to lower the engine RPMs at cruising speed if it isn't an overdrive transmission.
It's just a decision on whether you want to shift gears or not as to which way you go with the transmission.
My truck has a C-4 automatic. It's the first vehicle in nearly 30 years I've had that doesn't have a standard. While I like a manual, 30 years of shifting gears every day tends to get old. It's nice to get in a vehicle that doesn't have to be shifted for a change.
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Frmr Ford Trans Engr
Joined: Aug 1999
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From: SE Florida
But the C6 has a torque converter that multiplies engine torque by approximately 2:1. So that 2.46:1 ratio is equivalent to a manual trans with approximately a 5:1 first gear ratio.
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Lead Driver
Joined: Apr 2011
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From: El Dorado, Arkansas
A T-18 manual 4-spd has a 6.32:1 1st gear ratio.
A T-19 manual 4-spd was available with a 4:1 or a 5:1 1st gear ratio.
An NP-435A manual 4-spd has a 4.56:1 1st gear, NP-435D & L series has a 4.90:1 ratio and an NP-435E has a 6.69:1 1st gear ratio.
A T-19 manual 4-spd was available with a 4:1 or a 5:1 1st gear ratio.
An NP-435A manual 4-spd has a 4.56:1 1st gear, NP-435D & L series has a 4.90:1 ratio and an NP-435E has a 6.69:1 1st gear ratio.
Fleet Mechanic
Joined: May 2001
Posts: 1,396
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From: Cupertino
Advantages of a four-speed:
Less opportunity to leak
No external radiator cooling required
Cheaper to rebuild
Strengthens left-leg muscles and right-wrist muscles. Four -speed aces have a firmer handshake.
Lighter. If you drop one on your foot, it hurts less than a C-6
Saltier sound to pedestrians while accelerating and shifting out of a stoplight
Disadvantage of a four-speed:
You can't pick your nose or drink coffee and steer while accelerating from a stoplight
Semper Fi
Above subject to revision by Ultra
Less opportunity to leak
No external radiator cooling required
Cheaper to rebuild
Strengthens left-leg muscles and right-wrist muscles. Four -speed aces have a firmer handshake.
Lighter. If you drop one on your foot, it hurts less than a C-6
Saltier sound to pedestrians while accelerating and shifting out of a stoplight
Disadvantage of a four-speed:
You can't pick your nose or drink coffee and steer while accelerating from a stoplight
Semper Fi
Above subject to revision by Ultra
And me trying to REP ya.
Lead Driver
Joined: Apr 2011
Posts: 6,399
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From: El Dorado, Arkansas
Manual or automatic just comes down to personal choice. However, if I was going to the trouble to swap a transmission out, it wouldn't be to put another back in that didn't have an overdrive.
Lead Driver
Joined: Jul 2011
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From: On the Edge of the Desert
Originally Posted by Ford_Six
The torque converter does slip some at cruising speed, so really your cruise RPM will be about 200 higher with a C6. AOD and E4OD do not have this issue.
The lockup clutch in the TC takes care of that. Makes for cooler running temps as well.