Shifting issues from drive to reverse and back to drive

ANSWER : Mercedes has a dealer service order (#Order No: S-B-27.19/118A
) that addresses diagnosis, and possible dealer repair of the transmission for your model. Check with your dealer to confirm coverage of this.

ANSWER : This is an internal problem with the transmission and may be a valve body or leaking internal seal. The problem is the transmission leaking pressure internally, and when you put it in drive, the transmission is trying to go into reverse and drive at the same time causing the transmission to stall the engine. Have a mechanic, such as one from YourMechanic, scan the computer to see if a code is received that will help detect the cause. They will be able to diagnose your stalling issue, and any other problem you are having, so that a proper repair can be made.

ANSWER : Hi. This sounds like the ignition switch has a problem and is not allowing the car to go into park. If the ignition switch is not sending the signal to the neutral safety switch that the key is in the run position, it will not allow the shifter to move. It is also possible that the shift linkage is damaged and is causing the problem you have as well.

I suggest you have a certified technician, such as one from YourMechanic, come to your location to determine why the car is not shifting properly and suggest the necessary repairs

ANSWER : Hi there. There is a gear train issue with your transmission or a bad CV Shaft that is causing the transmission to shift had into gear. Since it shifts harder in reverse than forward, I suggest that the gears inside the transmission are worn. I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your transmission issue.

ANSWER : Hi there. The vehicle running great, once past the initial stall, leads me away from a fuel delivery concern. The stalling issue may be, the minimum airflow rate is not properly set. This could be the result of a dirty or worn throttle body. Cleaning and/or making an adjustment to the throttle body may correct the problem. Engine running at idle, plug the IAC passage, and the RPM (revolutions per minute) should be at or near 400 rpm. A vacuum leak present could also cause the engine idle to be improperly controlled and needs to be identified before any adjustments are made. I recommend having your vehicle’s stalling issue be diagnosed and repaired by a certified technician, such as one from YourMechanic.

ANSWER : This may be a result of low transmission fluid or potentially a faulty transmission control module. A faulty transmission control module may cause a delay in acceleration or erratic shifting of gears. The transmission control module has various sensors such as vehicle speed sensors, wheel speed sensors, throttle position sensors, turbine speed sensor, and transmission fluid temperature sensors that all direct information to it in order for it to perform it’s function. Other functions controlled by the TCM are components such as a kick down switch, traction control system, and cruise control module. Any of these may also affect the way the transmission control module performs and controls the transmission and the shifting of your vehicle. I would suggest having a professional from Your Mechanic come to your location to properly diagnose your transmission problem.

ANSWER : Hi there. A car that refuses to shift or go into gear easily is trying to tell you something is wrong and in most cases the culprit is the clutch (in a manual transmission) or torque converter (in automatic transmission). Transmissions are very complicated and have many moving parts, ignoring a hard to shift issue can quickly spiral into a very expensive transmission repair. Over time, especially as a vehicle goes over the 100,000 mile mark, parts and gears inside the transmission simply wear out. This process can be dramatically accelerated if the car is driven with low levels of transmission fluid. The transmission will have to be rebuilt or replaced which is a very expensive repair. Symptoms of a failing transmission include hard shifting, humming, clunking or grinding. It might be best to have one of our professional mobile mechanics come to your location and complete a car is hard to shift inspection, so they can determine the best course of action.

ANSWER : Hello – I don’t think this is related to switching back to 2WD per se. There is a shift position sensor on the side of the transmission, and it’s possible that the snow activity caused moisture and/or dirt to get into the sensor. I would recommend a transmission inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.