Transmission problem
 

My transmission switched hard under heavy acceleration and is starting to misbehave. It is on my 97 E420 with 165k.
Any idea how much of a problem, expense, I am facing? Any advice?

First step is to service ATF and filter if it hasn't been done within the last 60K miles. If issues persist after that, have vehicle hooked to SDS and trans data read...

ATF and filter were done about 20k ago, but not the torque converter. The oil does not look very fresh, however.

Was there an inordinate amount of sludge or metal in the pan when you changed it out? Skipping the TC leaves about 4 of the 8 liters in there. Did you use the correct ATF when you serviced it? How has it behaved for the last 20K?

On a side note, how old is your AMM (MAF)?

Have you checked the level of the trans fluid? If the level is on the low side you might want to check if the electrical connector on the trans is leaking. On my E320 this caused the trans fluid to wick-up from the electrical connector to the trans computer board through the wires. The fix is to replace the o-rings on the electrical connector, clean the circuit board if it is wet from the trans fluid and bring the trans fluid level to the correct level.

If your torque converter has a drain plug then I would have changed the fluid out when you did the filter change.

I ordered a new plug as well as oil. I will change the torque converter oil as well and get everything back to optimum and then see...

Also, like I asked before, are there any other driveability issues? My M104 experienced some tranny slamming and erratic shifting before I replaced the AMM. Replacing it restored normal operation.

The Mass air sensor was replaced about 6 months ago, no problems. I will change all fluids (including the converter) and hope for the best. It down shifts fine, and up****s fine under 3000 rpm. For higher rpm shift, I get a harsh engagement. It seems strange to me. No slipping, no other apparent problems. Just does not like to shift at higher rpms...