builthatch

i was driving last night with the transmission in S and it seemed as if it was hanging in a gear higher than it should quite often. speeds were in the 35-50 range and the revs stayed a bit higher than what seems like normal should be. also, sometimes, when it was doing this, whilst in S, if i depressed the right paddle, it would then go into the next gear and the revs would drop to what i feel was more appropriate.

does this sound normal? i can't recall it ever doing this before but then again i just don't drive this car very often so it's hard to say what it was doing before, or not.

it works fine in M and everything else seems ok. it's quite possible it has been doing this forever and i just haven't noticed.

AMGC

Yes it sounds like your tranny is shifting as they all do. Reset the TCU if you want the tranny to be more aggressive. To me it just sounds like you would prefer comfort over anything

AMGC

You said it held in higher gears but at the same time had higher revs than you think normal... Should be one or the other, you sure you didnt just hit downshift by accident lol

builthatch

i was not accurate with the semantics.

it'll stay in 5th whereas it seems as if it should be in 6th....or it'll stay in 6th when it seems as if it should be in 7th...all whilst in S...unless i tap the right paddle (sometimes). THEN it will drop to a higher gear (numerically).

if it's not in "automatic" in S because of playing with the paddles, it'll indicate the gear you've put it in next to the D (if i recall), but when you get back into auto, it'll just show "D". well, it would simply show "D" but not seem to be in the right gear...off by one, it seemed. and when it dropped to the next higher gear when i hit the right paddle, it still indicated "D". there was no change in the dash indicator despite me hitting the right paddle and the gear changing.

but yeah, it's probably normal. i will look up how to reset the TCU. thank you.

EDIT: i believe i've found the reset procedure? https://mbworld.org/forums/e-class-w...#ixzz3HXBqR4cT

i did the process detailed with steps in there and will go drive soon. thanks.

rohitC63

How does resetting the TCU make it more aggressive? What exactly does resetting it do?

Mort

I think S mode is just thinking you are driving aggressively and it is waiting in a lower gear than normal ready for you to get on it again. Sort of like in corners at a track. My 2010 used to do that from time to time.

dlefty

Based on description, I believe it is simply sitting there "hanging" at high RPM in the lower gear as it is anticipating acceleration. Pretty common. If you play with / feather the throttle in and out a bit, it will figure out your not getting back into the power anytime soon and up shift and drop the RPM's.

builthatch

i think you guys are right, thanks. my Q does something similar - whilst cruising it will keep the truck in a gear lower than it would otherwise be in.

AMGC

Resets the adaptive tranny so just makes the throttle more responsive or "aggressive" since most of us don't peel out at every light for the tranny to learn that lol

Television

Its been well proven by now that you cannot re set the gearbox ECU, it has a very small memory, just enough to adapt to your driving style as you are driving, and enough to store a couple of codes

2 of my cars have the 7g box, in the S mode it will hang on to the gears for much longer than in the C mode. The paddles on both while driving in top will knock it down by 2 gears and this requires to pulls of the right hand paddle to get back to top.

ENV²

My S mode does the opposite it literally is like having it in C mode. Shifts the same.

unelldl

Mine quickly upshifts from 3rd to 4th and 5th in S+ when I want acceleration and feel like I'm dead in the water! It's at dealer.

ZephyrAMG

Holding a gear in either 4th or 5th longer when transmission is adapting is ABSOLUTELY normal. Sometimes when driving the car aggressively for a change after a while of not driving or grandma driving makes me think the gear will never change or the transmission will explode...it eventually does.

Arjy

this happens on my MCT and seems normal. the car is in sport mode and is just begging you to rev the **** out of it rather than shifting up

unelldl

Hey guys!! The shifting problem as I described it was "shifting up to 5th 6th and 7th" when I wanted it to stay in 3rd or 4th for more power. When accelerating in 3rd it should stay there. Mine DOESN'T! A sporty transmission should downshift when pressing on accelerator not upshift!

zcct04

Under light throttle, quick upshifts from 3rd to 4th and 5th (or higher) are absolutely normal, regardless of what setting (C, S, S+) you are in. The MCT is quick to downshift when given enough throttle (probably more so in S or S+) but I often use the paddles to force a lower gear just to avoid feeling that I'm lugging it - I don't want 7th at 40 mph.

Quick upshifts under full throttle would indicate problems - the trans should hold to redline (7K in C or S mode, 7,200 in S+). When driven aggressively, the MCT is pretty good about sensing what you're doing and downshifting all by itself as you brake or corner hard. It will also hold the lower gears for several seconds afterward, anticipating that you may still be wanting to flog on it.

INS1GNIA

Put it in M and you won't have those issues lol.