Hi all,

Been a long time since I've posted here, but my trusty W123 is in need of a hand.

A few months ago I was out running errands in the 300. Everything was fine, was running and driving great. Went in to a Home Depot and when I came out, the transmission would not engage any gear. No forward gears, no reverse. Neutral and park seem fine. The trans gave me no prior indication that anything was wrong. It was rebuilt about 7 years ago.

First thing I did was check fluid. It was low, so I added fluid up to the proper level. No dice.

I checked the linkage between the shift lever and the trans on the driver's side under the car, and as far as I can tell, it's attached. This was later confirmed by having my Ms shift the lever in the garage while I watched the linkage from below.

At the advice of Jono from Blue Ridge, I hooked up a set of trans gauges to the working pressure port on the trans. The needle bounced like crazy but showed roughly 200PSI in park, and a steady 60PSI with the lever in D.

I was referred to a well regarded old-Benz tech nearby who was known for transmission expertise. Unfortunately, there didn't seem to be any real diagnostic done by them other than "yeah, it doesn't work right. Needs a rebuild dropped in, $5,500." Disappointing for a few reasons, but I had her brought back home.

I have not dropped the pan yet but imagine that's my next step. Is there a possibility that the B2 piston (I see it mentioned a lot) would be a culprit given the behavior I'm seeing? What else should I be learning about to hopefully remedy this? I'm not opposed to putting another trans in, but that it just all of a sudden with no warning stopped working makes me think it's likely something simple that just gave out. Any suggestions are welcome.

Thanks!