I know what you guys/gals will say. You just though of it after almost 10yr. But I do like to get a serious discussion.

How should you down shift on a Ml320 tiptornic. I usually feel I need to down shift when going up hill and feel I don't have enough power (I am sure many of you want to down shift on flat ground when you feel you don't have enought power too).

The questions is what should you do about the gas peddle. Of course you could do just about anything with the gas and the transmission is smart enought to take care of itself. But the questions is what is the most optimal for power and wear on the tranny. So here is the options.

1. keep the gas peddle the same and just shift.
2. Rev the engin when you shift. A sub questions to this is when and how much to rev. Do you rev just right before, during or right after? Or do you try to do the same as if it was a manual, rev while you shift? Same questions about how much to rev do you try to do the same as what you would do on manual (rev to try to match gears).
3. Let your foot off the gas and then shift. My think behind this is that less power (gas) being apply to the gears would reduces the changes of causing damage (may be a stupid theory). This is what I have been doing like I said it may be a stupit theory.

If am sure many of you many think of other options too...

thanks

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Silver Honda Accord, 2006
Silver G500, 2003
Silver SLK-320, 2002
Black ML-320, 2000
Bule Porsche 993 Targa , 1997
Silver Merkur XR4Ti, 1987

If you downshift the engine will have to rev higher to maintain the same speed. This burns more fuel in my opinion and the higher RPM on a increased load of going up hill seem to be more damaging then being in a higher gear at a lower RPM. This is especially true for towing or off road where torque is more important.

For the concern for fuel usage...I try not to use my cruise control (in resume mode) on uphill driving (i.e. country) as it seems programmed to try to get up to my predetermined speed too quickly. In a ML55 that a lot of fuel!

I find myself doing two things with tiptronic:
If I want sporty driving I'll drop a gear and use tiptronic. I also will start in 1st gear mode from a stop.
If I need to pass someone I'll leave my foot on the accelerator without increasing it and down shift. Then I will get on the gas.

In a manual transmission you would have to increase your RPM with your foot on the clutch before lowering a gear to be smooth. Like in "Heel and Toe" driving.

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1988 Mercedes-Benz 300E 5 Speed ~200k
1958 Mercedes-Benz 190SL (sold)
2000 Mercedes-Benz ML55 AMG ~230k - FOR SALE
2003 Audi A4 1.8T Quattro - Wife's Car
2007 GL450

If you just pressed the throttle enough to create a downshift, well ... you would have pressed the throttle.

You're obviously looking at higher revs when you force a downshift, so if you don't want to just slow down you're going to have to press the throttle.

I really think doing what you would do naturally is the thing to do, and that's pressing the accel pedal.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles