PSA: if you've got a clunk taking off from a stop - PeachParts Mercedes-Benz Forum

mabbonizio · #1 12-05-2016, 09:33 PM

Hi Folks,

this may be common knowledge to some so if it is please just dis-regard.

My differential appears pretty worn with quite a bit of play in it (not axles nor driveline).

Coincidentally my 82 240D has been starting in 2nd gear and bumping to 1st gear about a second after the brake pedal is released and throttle pedal applied.

This bump off the line coupled with the worn diff is REALLY annoying.

After doing a little research I concluded that I should check my 3/2 valves and levers on top of the valve cover. Apparently the car is supposed to idle in D in 2nd gear but start off in 1st gear as soon as the throttle pedal is applied. This allows a smoother idle and quicker take off.

I checked my valve levers and noticed they were worn, but still present. I removed them, built them in CAD and then 3d printed new ones on my printer to test if they were actually the issue or not.

Well, they were! replaced the little worn levers and my car now starts nicely in 1st gear.

I think I may have made them too thick as the car seems to idle in D in 1st as well which is quite rough, but still much better than the annoying clunking. I'll be ordering OEM replacements asap.

Long story short, if you're car is starting off in second and bumping into 1st check those little levers on the 3/2 valves!

kerry · #2 12-05-2016, 10:48 PM

Some models are designed to start off in 2nd gear (non-turbo 300d's?) and only start in first if accelerator is pressed to the floor or if shift lever is moved to 1 and back into D while at a stop. Others (116 SD's?) are designed to idle at a stop in 2nd and shift down to 1st when the accelerator is pressed.