1999 ML320 Not Shifting - It's a Puzzle

Hello All,

I'm hoping someone here can help me identify the problem with my transmission. My 1999 ML320 needed the motor mounts replaced. It was shifting perfectly, and I put it in the shop. The mechanic explained that he could either unplug everything on the engine and remove the engine to replace the motor mounts (a 16 hour job), or he could lift the engine (as is) with a jack to replace the motor mounts. The goal was to save time/money. It turns out that this is what most knowledgeable mechanics do. However, he didn't know he had to remove the shifter.

When the ML320 came was reassembled, the transmission wouldn't shift, and the shifter was broken. I bought a used shifter in very good condition on ebay. We installed the new shifter, and the ML320 was shifting again... but, only for about 10 minutes. We decided to check the transmission fluid. We noticed that the transmission fluid was orange/silver... metal shaving in the transmission. We chan ged the transmission fluid, and the ML320 was shifting again... for about 10 minutes. Then it started getting stuck in specific gears, off and on ( shift up to 4th, but only shift down to 3rd at red light, then back up and down randomly).

Upon further inspection, the mechanic noticed that the connector on the conductor plate of the transmission was damaged, so I ordered a new conductor plate and we replaced it. The ML320 still doesn't shift automatically. It will engage 1st through 4th gears if I shift it manually, but it won't cycle through the gears automatically. Does anyone have any ideas of what to look at next? Any help is greatly appreciated.