2002 ML500, gear selector shift-handle jerks upon take off - PeachParts Mercedes-Benz Forum

Bigdaddybenz · #1 08-07-2011, 09:30 PM

Hi guys....

I have a 2002 ML500 with 170,000 miles on it that is displaying symptoms of something that I believe can only get worst.

Upon take of, from a dead stop, there is a "thud" sound emitted from under the vehicle's center, accompanied by a slight hesitation before the vehicle begins to move.

It doesn't happen every time, but the frequency increases if I accelerate a little harder than usual, from a dead stop.

In an attempt to gather as much preliminary information as I could, I pulled into an abandoned parking lot to see if I could reproduce the malfunction at will or under certain given circumstances.

During this process, I discovered that the gear shift selector's handle would literally jolt about 3/16ths of an inch whenever the "thud" sound would occur during acceleration from a dead stop.

The shifter-handle's movement was more pronounced if I increased the torque, as if it were responding to the torque created by a more aggressive take off from a dead stop.

I also noticed a slighter movement of the shift-handle when I purposely manipulated the acceleration as to force the transmission to shift harder into 2nd gear.

Any suggestions????

I am a former mechanic, did lots of work on the older model Benz s that I've owned, so I'm not too intimidated, but my knowledge of the M Class 4 wheel drive system is zilch........I'm kind of hoping that it's probably a worn transmission mount, or maybe a damaged flex disc (if these MLs even have one) :-)

Thanks in advance, any advise will not only be greatly appreciated but implemented to the utmost!

Dee

mbdoc · #2 08-08-2011, 08:28 AM

Either the motor/trans mounts are completely broken OR the chain in the transfer case is severely worn & jumping.

Bigdaddybenz · #3 08-14-2011, 05:23 PM

Thanks MB Doc!

I jacked the vehicle up, checked the transmission mount, it appears to be fine....I can honestly tell you that at any given angle I could not see either motor mount in its entirety.....That said, I decided to take a jack and a block of wood to the engine's oil pan, to see if I could slightly lift the engine and notice an exaggerated movement near the mount areas......Passenger side barely moved but the Driver's side mount moved upwards approximately 1 and 1/4 inches......I assume that this mount is completely broken......The Driver's side mount is located directly above the front axle's pumpkin and access appears to be extremely limited......What is the best and simplest way to change this particular mount????

Thank you all!

Dee

mbdoc · #4 08-15-2011, 08:22 AM

Replacing motor mounts on that ML takes a good MB tech about 3-3.5 hrs...

duxthe1 · #5 08-17-2011, 11:41 PM

"What is the best and simplest way to change this particular mount????"

Pay somebody else to do it! Seriously. Unless you have access to a lift, a jackstand, a well equipped toolbox, and small hands... that is.

There isn't room to lift the engine far enough to clear the mounts. You have to first remove the mount arms from the engine. Did I mention that the A/C compressor blocks removal of one of the arms. You get the picture, pay somebody else to do it.

MBDOC, my best time is around 1.75hr though it's rare I'm motivated to work that hard.