dicktahoe

"Forcing a downshift to slow down wears the bands or other friction materials in the transmission, just as braking wears the friction materials there. Brakes are always more efficient and less costly than the friction materials in automatics, especially complex ones like the ZF 8-speed your car has."

Bands? Other Friction Materials? Maybe back in the 50s but not now. The Only friction material in the transmission is the Clutch. When you use the Paddle Shifters to downshift, the clutch releases, the engine is sped up to match the new speed so there will be very little clutch wear and then the clutch re-engages. See the attached picture and try to find the bands!

fEArmE

Interesting! If you are about come to a stop, the transmission is going to down shift anyway. I don't see how "forcing" a down shift earlier within reasonable engine speed to slow down the car can do any harm to the transmission. Like Oscar2 mentioned, the purpose of the transmission unit is to shift to lower gears and let the engine compression stroke to do its job. If there is wear and tear involved, I would be more concern about the engine, not the transmission.

last911

Your illustration is of the dual clutch tramsmission, not the ZF 8 speed automatic with torque converter. There are no bands in the S-tronic.

tompas

Excellent analogy!

I Have no idea if I'm right, but I've always "exercised" all of my cars and bikes ... occasionally giving them a gradual climb through the RPM range and back down again. Add some Techron and you have an Italian Tuneup.

Anyway, I always thought of well timed downshifts and the back pressure it creates as something helpful in keeping an engine responsive. And its fun!

Just finished my 1st week with my new to me 2012 A6. As a result of lurking here for a while, one on the prerequisites when searching for my A6 was the "Sports package". Where I find myself using the paddles the most is when I'm in D, downshifting to engine brake or for added acceleration when passing without hitting the gas peddle hard.

Even when I'm in manual mode, when decelerating I find myself downshifting more with the paddles than the shifter. Don't really know if I'm hurting the transmission or engine, although well timed shifts feel so right I don't see how. And none of my well maintained and "exercised" engines or transmissions ever gave me a problem...and (knocking on wood) I hope my A6 doesn't either.

This is such a fun car!

newmoon

The attached image is of the correct 0BK 8-speed auto, and it is one page out of the Audi Self-Study Program for this transmission which you can find by Googling "Audi SSP 457".

This transmission has 2 multidisc brakes and 3 multiplate clutches that hold certain elements of the planetary gearsets in place to engage the desired gear ratios. Because the brakes and clutches are friction elements, every shift will gradually wear them down, but in particular doing high-rpm DOWNshifts will place the most strain on them because of the large jump in rpm that they need to engage.

Eventually when the brakes or clutches are very worn out (perhaps at 150k+ miles), the transmission will not be able to hold certain gears, especially under full throttle acceleration, and the transmission will appear to 'slip'.

tompas

This make a lot of sense. What I've noticed is that in "drive" it's always at at relatively low RPM. Do you think that coming down from 8th gear when getting off a highway with a series of paddle downshifts bringing the rpms back up each time to around 2800 rpm would create more wear than the transmission doing it automatically at a lower RPM?

snagitseven

All of this talk about wear and tear of the transmission seems to me to be essentially a non-real world issue. I have to believe that these mechanisms have been designed to upshift and downshift for many more cycles than is being discussed. I've had four Audis, one of which was for about 100K miles (and many other auto transmission cars with manual shift capability) and not once did I ever encounter a tranny problem despite consistently using them for downshifting (my grandmother survey). Also, one perusing the various AW forums would be hard pressed to discover a plethora of threads complaining of transmission failures - engines and other systems yes, trannys not so much.

I think about it like this...would a quality pair of running shoes wear out faster if the wearer was running vs. walking? Probably, but would the difference be significant? Probably not as the manufacturer designed the shoes for running. Will frequent downshifting cause additional wear over many years of use? Likely, but will it significantly wear the transmission for the average years of ownership? Doubtful.

I suspect after the many iterations of development, the ZF trannys are designed to easily handle frequent up or down shifting by the average driver for quite some time and longer than other car mechanicals. On the other hand, by virtue of their design, brakes require replacement much more often regardless of whether or not downshifting is employed. Kinda like socks compared to those running shoes. (My socks anyway).

tompas

A logical, common sense approach ... which allows me to have guilt free fun in my new car!

BTW Snag, I like your car. I had to scour the internet (autotrader, cars.com and the Audi CPO site) for up to 500 miles from my location and only came up with one car that matched my criteria - a fully decked out CPO A6 3.0T Prestige, Quartz Gray w/Black interior, 19" Sport, Driver Assist, Innovation Pkg w/LED headlights, and B&O for under 40K. Except for having to settle on the Bose vs B&O, my CPO A6 has got it all including a nice tint job and new tires with and has only 34.000 miles.

What a gorgeous, fun car!

Thanks BTW for your MMI post. Already put a lot of your recommendations to good use.

newmoon

Yes it would create more wear, but how much more is the topic of this debate. If you don't intend to own the car past 150,000 miles, I'd say don't worry about it. And even if you do own it past 150k miles, at that point the car would be worth so little that it is not cost effective to repair anything that breaks, including the transmission.
Actually there are quite a few threads if you search for "transmission slipping", all on very high mileage (100k+ miles) Audis:
https://www.audiworld.com/forums/a4-...ssues-2879479/
https://www.audiworld.com/forums/a8-...g-2-a-2876667/
https://www.audiworld.com/forums/aud...pping-2875224/
https://www.audiworld.com/forums/a8-...03-s8-2876870/
https://www.audiworld.com/forums/a6-...pping-2872702/

And who doesn't know someone with an old junker from any manufacturer where the transmission is shot and doesn't hold gears anymore?

snagitseven

Which is exactly the point of my post. Don't worry, be happy - downshift away as desired. And if you do plan on keeping the car for more than 150K miles, the transmission will be only one of the many things you should start saving up your dollars for now.