Manual Mode Engine Braking

[pajeff02]

Both our '10 Cadillac and '12 Challenger have the manual mode automatic transmission where you can move the shifter over into another gate and then manually ratchet up and down through the gears. Having been raised on stick cars, it is more of a gimmick than anything else and I rarely use it. I have always wondered though about using manual mode to downshift for engine braking on hill descents. We live in the hills of northern PA and with some of the dumbass drivers we have around here my brakes get a real workout. Yes, brakes are easier and cheaper to replace than a transmission, but I honestly wonder if utilizing manual mode in this fashion is contraindicated?

[Naaman]

Hang on, let me get my dictionary....


Okay! Got it. Now I can respond!

FWIW, I use it on "proper" automatics all the time. Though, it annoys me when a 5-speed transmission limits the driver to selection between D and D3 (no D4 option), such as my wife's car does. Now, I don't know if this actually addresses your question or not (for example, why not just put it in D3/D4 or whatever?). Basically, if I had access to a sequential shift, I'd probably select one gear lower and let it ride down the hill, sparing the brakes as much as possible.

The owner's manual seems to hint that using the autostick mode will improve transmission life as well as the overall performance of the transmission in situations where frequent shifting is required (look around near page 380). The manual seems to imply that engine braking on a hill is one of the intended functions of the manual mode.

[pajeff02]

Thanks. On old school automatics, I would only downshift manually when towing between OD and D, never to a lower gear than D though. I guess it makes sense that they are designed to handle it, just never felt comfortable using the newer transmissions in that manner.

[Naaman]

Yeah. I guess they got rid of the "OD" terminology because it was confusing (?) I don't get why my wife's 5-speed doesn't let me turn off OD. The 4th gear in that thing is not even 1:1. It's 1.xx:1, with 5th being the OD.