Transmission, Primary vs secondary setting

[CaptMilks]

2025 Europa 32KD, 6.7 with Allison 6 speed. The transmission looks to have three modes, Primary, secondary and manual. The Freightliner Manual says the secondary setting can be programed. My question is how did it get programed? Is it a tow haul mode? Seems to have more power than the primary setting.

[NewToTheForce]

Originally Posted by CaptMilks

2025 Europa 32KD, 6.7 with Allison 6 speed. The transmission looks to have three modes, Primary, secondary and manual. The Freightliner Manual says the secondary setting can be programed. My question is how did it get programed? Is it a tow haul mode? Seems to have more power than the primary setting.

That's interesting. I know not apples to apples, but our 2023 Force's "secondary" mode is Eco mode. In Eco it starts in 2nd and shifts sooner (lower rpm) than it's primary mode. These are programed at the factory and can be reprogrammed at select facilities.

[CaptMilks]

It seems in Primary the shifts are slow to drop down. Pulling the Jeep its far better in secondary on the highway. Looks like I got better gas mileage too which doesn't make sense.

[CaptMilks]

Dealer told me Primary = Eco and Secondary = Power/tow haul

[NewToTheForce]

Originally Posted by CaptMilks

Dealer told me Primary = Eco and Secondary = Power/tow haul

A quick run should be able to verify which is shifting at lower rpm's, and possibly starting out in 2nd.

[Europa32KD]

Manual is independent of primary or secondary. You can select manual in either mode.

Primary starts in first gear and has higher shift points and downshifts sooner.

Secondary starts in second upshifts earlier and doesn't downshift as early.

You can think of secondary as eco mode.

In manual mode, you are selecting the highest gear attainable. You are basically selecting the possible range. For example if in primary and manual, with 4 preselected you are allowing gears 1-4. In secondary, with 4 selected, you are allowing gears 2-4.

If you preselect 1 for low speed operations so that 1 is the only allowable gear, it will allow you to obtain torque converter lockup in gear 1. Otherwise torque converter lockup doesn't normally happen until gear 2.

Also, if you preselect too low of a gear, it will not allow you to obtain that gear if it will over speed the engine. It will downshift one gear at a time without over speeding the engine.