My tranny finally gave out on my '77 300D, I towed it with strap for approx 7 miles a few months back, hurt tranny, slipping, etc, then just doesn't want to move the other day.

Shortly after that happened I bought two "spare" used auto trannys. Each seller said that theirs would fit in my 300D.

So here are the #s stamped on the sides of the tranny:


722 111 123 270 07 01022225 - tranny currently in car that's toast

115 270 1701 25430 - tranny purchased from Benz Friends in Seattle

126 270 55 01 722 300 02 611872 - tranny purchased from private seller, said it was from an '82 300D non-turbo, said it'd fit in mine. Had a 300TD in his garage he was working on, seem'd to know his stuff (famous last words).


Both "Benz Friends" and private seller said theirs would fit in my '77 300D.

So which one (or both?) would fit my car?

Ryan on Camano Island

There are different transmissions for the W123 body at least up to the end of 1980. The first is part number 123 270 07 01, was used on the early 300D's up to serial number 086898 with a few exceptions. The second is 123 270 36 01 which has a vacuum kickdown. The third is 123 270 37 01 which also has a vacuum kickdown. I do not know if the second and third version will interchange. According to my info, all the transmissions are 722.118 models, but that does not jive with the number from your tranny. I also know that early 300D's had a linkage for the kickdown rather than vacuum.

The 115 270 17 01 would be for the older body style, and 126 270 55 01 is for the full-size body. I would not bet that the 126 transmission came from a 1982 300D non-turbo, as all 1982 models were turbos (unless it was a Euro model), and according to my repair manual, all W123 300 models had either the 722.118, 722.303, or 733.315.

I can't tell you if the ones you have will fit, but I would say the things to look for are what type kickdown mechanism it has (linkage or vacuum), bolt pattern on engine, overall length, rear mounting, and driveshaft connection. Even if they are not the right one, they may still fit. I almost guarantee the 126 transmission has the vacuum kickdown, so would be a pain to retrofit if yours has the linkage as you would need all the vacuum valving mounted to the injection pump and valve cover. And I bet the 115 has the linkage, which would be indicated by a lever on the right passenger side.

Hope this helps.