Tow/Haul off or on(ram)
I w the discussion about the ford tow/haul system, how about the Ram in our case, 2017 1500 with the hemi and 8 speed we use T/H all the time when towing and definetly see a difference in accelera...
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Lynnmor wrote:Grit dog wrote:
^ But it does have a gear ratio or 2 that are close to 1:1, so what’s your point?
Many newer auto transmissions don’t have an exact 1:1 ratio gear any longer. And many do.
What is worth noting, is there is nothing magical that happens at 1:1, it’s just another step in the gear ratios from under-driven to over-driven.
And “OD off” is a thing of the past that was used on 4 and 5 speed transmissions to limit upper gear ratios. No different than manually shifting it via the gear shift or range buttons to limit the upper gear that the trans will shift into.
I’ve not seen it on any vehicles I’ve driven in recent years that have 6 or 8 speed transmissions.
The point is that older transmissions had a direct drive straight thru the transmission and didn't have the friction of running it thru a gear set.
Automatics do not have "gear sets"
Sam Spade wrote:RoyJ wrote:
I'd like to know what transmission does that.
Maybe I'm a few years (decades ?) behind on transmission design.
I though that the LAST thing that happened on up-shifting was locking the torque converter.....AFTER the highest gear was engaged.
Then anything that took it out of the highest gear (overdrive) ALSO unlocked the converter.
I assume you are saying it doesn't quite work that way anymore ??
Torque converters have been able to lock in at least direct and overdrive since there have been lockup torque converters.
Lynnmor wrote:RoyJ wrote:
I'd like to know what transmission does that.
In most, OD off means exactly that - overdrive gears are not used, only up to and including direct drive.
Again, *most* transmissions would lock up sooner in direct drive, with OD off. I've never come across one where in OD off it stays in direct but with the converter unlocked.
You might want to check what transmissions have direct drive, mine doesn't.
I've yet to see any transmission that didn't have a direct gear.
OP:
Tow haul mode should be used any time you're doing towing or hauling. You should not have to force a downshift on a modern transmission.
