Automatic Transmission Compatibility info Needed
 

Year: 1985 Model: 300D non-turbo Euro version. My Transmission is basically shot. Something inside broke, and scored the splines machined into the case. I'm trying to find out what easily available transmission would fit. I have been told that the US Turbo might, but with a different drive shaft. I will need at least a rebuildable core, or a used transmission. My part number is 123 270 56 01 722 405 02 116469. The sad part is, I have a standard that my mechanic said might fit, (sent to me in error when I had to buy a 5 speed for my 300E Euro from Germany) but I don't have a donor car for the rest of the parts. I'm not real concerned about the gear ratios, this is a second car and does not see much use. Just as long is it won't blow up. I can get one from Germany again, but at about $850 plus shipping, I hope I can get one here a bit cheaper.

Any help would be greatly appreciated. My local mechanics are split on what would fit, and the people here have been helpful in the past. Thanks again.

I believe it would be a 722.405 according to the part number. So a 722.4 trans is what you'd need. Maybe one from a Cali 85 300D? Those came with 722.4 transmission right?

I'm still trying to figure out the numbers, so I don't know. I used to live in Cali, well Bakersfield anyway, and some folks don't think that counts. What I'm wondering is if anything else would bolt up. I think I found one in AZ, but I live in Georgia now, and the shipping is a killer. CA would not be any better. My mechanic and one of his employees are arguing over what fits, and that leaves me a bit uncomfortable, when I will pay for shipping.

I'm not too sure about the AT compatibility, but if it makes you feel any better, that 300E trans wouldn't fit your car without some serious mods... the bellhousings are not the same, because the 300E has the starter on the left, while the 300D has it on the right.

Springbank:

1) Is your car's chassis type a W123, or a W124?

2) Is the starter motor on the left, or on the right side of the engine?

Yes, the 126 has an electric speedometer, and the 123 is mechanical. I believe (someone correct me if I am wrong) that a 722.3XX will work as well. A trans from an '82-'85 123 should work, with the exception being a TD, as it has the electric speedo as well. In a pinch, a 722.1XX would work except for it having a control rod instead of a bowden cable (722.3&4), and some being vacuum only (no control rod). I have an '81 with the 722.1XX and a turbo engine from an '84 that work superbly together....Rich

It is a 123 (detailed in the first post)

I think the starter is on the left for all W124 and on the right for all W123s.

It's not a transmission for a 300E, they sent the wrong one, and had to send the right one on their dime. I'd have to look at the numbers, but I was told it would fit a 300D with a manual.

A 300D could be a 124, and thus would take a different trans than a 123 300D (manual or automatic). As far as I know, all the transmissions that have the starter on the left side are for engines with an aluminum head, Diesel and gas. All the iron head engines need the trans with the starter on the right side. Regardless of the trans number, as the same prefix (722.1,2,3,4 etc) was used for both engines.

I think we are saying the same thing. However, there are not many 123's here in America with anything but a Diesel engine, so the above point is moot. The OP is looking for a replacement trans for a 123 with a Diesel engine, so that leaves out most if not all transmissions from any other chassis (the rare exception below). I am basically saying that there are many different transmissions available within the 123 chassis and others that will work. The M110 engine in any of the chassis (123,126,116) would use the same trans as well (starter on the right side).

I would be most inclined to use the manual transmission. However, this will require a manual transmission flywheel (one from a 240D will work) as well as a lengthened drive shaft, master and slave cylinders, pedal assembly (240D parts work), and a manual transmission brake fluid reservoir (once again 240D parts work). It's quite a bit more work than just swapping one slushbucket for another, but totally worth it IMNSHO.