Shifting seneca 37ts

[jrwldr]

What would be the reason to shift from drive to 3 while driving?

[Robbbyr]

Originally Posted by jrwldr

What would be the reason to shift from drive to 3 while driving?

Only if for some reason you did not want the transmission to upshift into 4th gear or higher. Or if you want to force a downshift to gain more engine braking under certain conditions.

The transmission won't let the downshift happen if your road speed would cause engine overspeed to occur. Example would be traveling 65 mph and downshift it to 3rd. It won't actually shift into third since that would cause engine overspeed and potential catastrophic engine damage.

[jrwldr]

OMG thank you so much. I was thinking about when going up steep grades too.

[Robbbyr]

For the vast majority of situations you can leave it in D and be fine. It will upshift when appropriate as you accelerate. When you slow down with the engine brake turned on (dash switch) it will tell the transmission to downshift to provide more engine braking as you slow.

So the conditions are fairly limited when you will need to have the shifter in anything over than D when traveling.

Not that it matters, but what year Seneca do you have? A brand new one with the electronic shift pad or one with a shift lever?

[SloPoke]

Originally Posted by Robbbyr

Only if for some reason you did not want the transmission to upshift into 4th gear or higher. Or if you want to force a downshift to gain more engine braking under certain conditions.

The transmission won't let the downshift happen if your road speed would cause engine overspeed to occur. Example would be traveling 65 mph and downshift it to 3rd. It won't actually shift into third since that would cause engine overspeed and potential catastrophic engine damage.

X2

On a 8% grade coming downhill with the trailer fully loaded and the total rig just under 33,000 Lbs. Put it in 3 and let the engine brake keep you at 35-40 mph without having to use the service brakes.