300D transmission in a 300SD?
 

I got a replacement transmission for my 81 300SD. It's marked 722.315 which I believe makes it a transmission out of an 82-85 300D/CD/TD. It is physically identical to the original transmission.

The only concern I have is that the SD is heavier than the average W123, however, I have to think the GVW of a 300TD is not much less and possibly greater than the GVW of an SD.

Any thoughts?

Thanks,
Sixto
91 300SE
81 300SD

The only real difference was the speedo drive (cable drive or electronic). As long as the replacement has the provision for the electronic speed sensor, it should work fine.
Regards,
Randy D.

Randy,

Thanks for the info. The main housing says 722.315, but the tail housing has a 126 part number and the same plastic cup in the speedo drive as the transmission that came with my 81 SD. If this transmission was meant to drive a speedo gear, I don't see how it could.

Of course, that's of little consolation since the locating pins are much bigger than the corresponding holes in the engine. I'm tempted to drill out the engine side just to make it work :eek:

On another thread I boasted that I replaced a 116 LWB transmission without removing the driveshaft. I wasn't so lucky with the 126 SD.

Sixto
91 300SE
81 300SD

An owner of a junk yard told me that they were different in length. I guess if the drive shaft can slip in, it won't be a problem then.

I had the transmissions side by side and measured them as well. FWIW, I think the difference is that the 116 LWB allows the driveshaft to dip more in front. The 126 SWB driveshaft is more restricted when still attached at the center and diff.

Sixto
91 300SE
81 300SD