mlgbwk

Car has 800 miles only so far Shift was absolutely smooth till last week. Last Friday morning, I notice there IS a behavior change in the transmission, usually when I go for 30-40 mph, there is a hard gear shift, maybe between gear 3 and 4 out of 7, not sure since I can not tell which gear I am at, RPM drops from 2100~ to 1500 suddenly and it feels really hard.

Never had this problem before and this ONLY happens around 30-40 mph, once I pass that gear tranny is very smooth during shift.

I searched and found someone get the tranny "reflashed", so my Q is:

- After reflash, how long will it keep in factory default mode and will it "adapts" to my driving style and run into this issue again? I drive pretty gentle and I cannot think of any reason for the tranny to change its behavior.

- What is the difference between "code, warm, hot" mode of tranny? Is it refer to the temp of engine or sth else?

another unrelated Q: when you put it to R gear, will the passenger side mirror tilt down? Mine (base model) does not do this, not sure it is part of some package.

Thanks everyone!

T

MBRedux

If it's a 4-Matic (you failed to mention that) I would take the car for a SMYS run. Warm it up, then go on the freeway. Punch it while in the acceleration lane. Notice how it behaves. Take note of the down shift when you gun it, and then each of the subsequent up shifts as it climbs to speed. (you pick that number). Now do the same in "S" mode and take notice if there is any difference. If you do notice early shifting, shift hesitation (shift hang or lag), or downright "noisy metal", its a sure bet that either the systems CU was corrupted, and needs a flash, or the transfer case has failed in case the metal sound is heard. Time for a trip to the dealer. If not, then everything okay.

mlgbwk

Thanks for the info! It is RWD, not AWD. Actually the problem is less noticeable if I test it on freeway or if I apply gas more aggressive than usual, and it ONLY happens between 30-40 mph.

There is no noisy metal thing during tough shift.

What is SMYS run? I will try S mode and see if there is any difference.

Thanks!

MBRedux

My guys at the shop dubbed the term ... a SMYS run = "Show Me Your Sh*t" run. It's where the car shows you what it can do, what it is capable of when pushed to its limits.

I would take it in and show the service tech. May need a flash.

GLKKa2H

It's a quite interesting advice given to the OP - when the GLK Operator's manual with regard to the break-in period (first 1000 miles - OP GLK 800 miles) reads: "Avoid overstraining the vehicle during this period, e.g. driving at full throttle."

GLKKa2H

It should be "tiltable" even on a base model, however is the parking position to be "set and stored". Check page (#) 99 of the 2012 GLK Operator's Manual: http://www.mbusa.com/vcm/MB/DigitalA...-GLK-Class.pdf.

And: The button for the exterior mirror on the front-passenger side to be pressed for activating the function (red LED lit).

MBNA109

Agreed.