2019 RAM 2500 6.4 8 SPEED MPH AND SPEED CHARTS vs 6 SPEED

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WAKEMASTER

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I thought I would throw this together quick. This chart compares the new 8 SPD ZF transmission to the current 6 SPD 66RFE transmission.

** I am not able to confirm the exact transmission ratios of the new 8 speed. However I would think that the ratios should be very close to what is on the ZF website for the 8HP75.

**I also assumed a 33.2" wheel in the calculations

** I put this together really quick so....

View attachment 152204

RPM6.4.jpg
 
Last edited:

dbctmc

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Thanks. Does anyone know if the 8 spd is manually shiftable? In the photos I've seen, there is not a "M" setting on the shifter dial.
 

olyelr

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Thanks. Does anyone know if the 8 spd is manually shiftable? In the photos I've seen, there is not a "M" setting on the shifter dial.

If its like the half ton’s, the manual shift buttons are on the steering wheel.
 

JoeCo

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Thanks. Does anyone know if the 8 spd is manually shiftable? In the photos I've seen, there is not a "M" setting on the shifter dial.

Edit olyelr beat me to it.
 

crash68

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Thanks. Does anyone know if the 8 spd is manually shiftable? In the photos I've seen, there is not a "M" setting on the shifter dial.
If its like the half ton’s, the manual shift buttons are on the steering wheel.
The Gear +/- buttons limit the highest gear the transmission will shift into, it they won't force an up-shift.
I'd be willing to bet the Tow/Haul mode won't lock out 8th gear either. It's a false rumor that the T/H button locks out gears on the 8spd, it only appears that way because your not going fast enough to warrant being in those gears while towing.
 

RainDesert

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Here's a pic of the gear limit buttons on the new 2019 2500 6.4 on a lot near me.2019ramshifter.jpg
 

olyelr

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The Gear +/- buttons limit the highest gear the transmission will shift into, it they won't force an up-shift.

And isnt that pretty much how any auto tranny in the world works, regardless if it has buttons or a large stick on the column?
 

crash68

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And isnt that pretty much how any auto tranny in the world works, regardless if it has buttons or a large stick on the column?
Some people had the delusion that pushing the Gear + button that it would force an up-shift with the 1500 8spd, it doesn't.
It's good to see Ram states "GEAR LIMIT" on the buttons now.
 

JoeCo

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Some people had the delusion that pushing the Gear + button that it would force an up-shift with the 1500 8spd, it doesn't.
It's good to see Ram states "GEAR LIMIT" on the buttons now.

I just use it to shut off mds, but that being said yes I just put it in 8th and let it work as usual.
 
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