CFeria

A8 trans was wondering, is it safe to shift from Auto to Manual or manual to auto while driving?

Thanks!

Kraz8s

It sure is!

NSC5

Yes, and you can also use the paddles while in auto mode which will cause it to temporarily go into manual mode.

The control system won't let you select a gear which isn't suitable for the current vehicle speed so trying to select too low or too high of a gear will result in shift denied.

The A8 protects itself against almost everything except its torque converter is susceptible to damage from the very poorly implemented AFM system but manual mode avoids that issue since it prevents V4 operation (unless you have the driver mode in eco).

Power Hawk

Been there, done that. No problem. Enjoy.

CFeria

Thanks Much EVERYONE!

As far as AFM I have been doing everything possible to stay out of it, only drive in sport, or tour and I do normally use the paddle shifter to downshift 1 or 2 gears but not under load, this is only to vary the rpms since it only has 200mi.

NSC5

The A8 is very easy to drive as a manual because it will downshift automatically as the vehicle slows so the only time you need to use the down paddle is when a lower gear is needed for more power during such as passing.

Are you still in the early break-in mileage? If not if you forget to upshift the engine is governed at its rated RPM so you will simply stop accelerating. However if you are still early in the break-in mode the governed speed is above the lower recommended engine speed during initial break-in.

The A8 controls pretty much prevent user caused damage. You MIGHT be able to overspeed the engine by manually selecting a low gear for a steep descent and never using brakes but that is about it; other attempts to select too low of a range will be met by the "Shift Denied" message.

owc6

Virtually impossible to over-rev the car; it will deny a down shift if the resulting rpms will be too high, or it will run up against the rev-limiter when accelerating.

Patman

I really don't understand why GM only has AFM disabled when in manual mode on the A8! With the M7 cars it will only allow AFM to operate when in eco mode, so why don't they do the same with the A8? It would probably save them a ton of money in warranty work, as a lot of A8 owners probably don't put the mode into eco mode very often, and I bet most don't put it in manual mode that often either.

NSC5

I suspect it is tied into the CAFE calculations (which are separate from both the EPA estimated sticker calculation and the mileage calculation used for the gas guzzler tax). It has been a long time since I looked in depth at CAFE but since the stated requirements are so high I expect they allow assuming an unrealistically large contribution from any fuel savings device. Because V4 mode is more intrusive with a solid clutch connection it is easier to force the automatic equipped C7 into V4 under conditions that would produce unacceptable levels of vibration were it not for the ability of the torque converter to dampen the vibration. But the cost of that is cycling the the torque converter clutch continuously with resultant issues for the torque converter.

DALE#3

Broke mine in mostly in Manual Mod.Exhaust open,all touring.Tickled the 4000 rpm max a couple times.
The temptation is their....But,Not Yet.Suppose to vary your rpm's.You'll vary your rpm's. more in manual.ENJOY!