722.303 300SD
722.315 300D

I have searched the archives and I can't find the difference between the two. The only thing I could come up with was the speedo sensor. I found another post that said they were directly interchangeable (found in Tech Help).

My 722.315 transmission in my 1983 300D is a little shaky. I have a 1981 300SD donor car with a perfectly good 722.303. There's got to be a difference, but what is it?

In some of the research I am doing on the transmisions I have found that the 722.303 transmision is used in the 1981 to 1985 300SD. The 722.315 transmision is used in the 1982 to 1985 300D. I'm sure the base transmission is the same, but what is the difference?

For one thing, the 300SD has an electronic speedometer with an inductive pick-up in place of the mechanical cable in the 300D. You can swap tail housings to make it work.

Sixto
95 S420
87 300SDL
83 300SD

That sound reletively easy and explains the difference in the numbering.