W123 4spd swap driveshaft question
 

I'll try to make this as short as possible

So- I just snagged a 1983 240d 4spd, wrecked in the front. Was running and driving as of 4/13/19 (day of wreck) with 175k on the odo... unsure if that is accurate or not.

I'm harvesting the trans and all associated parts to go into my 1983 300D.

Obviously, per everyone else that has done the swap i suppose, some points of concern/modification are:

1.) Driveshaft length
2.) Shift linkages
3.) Flywheel
4.) Crossmember (use auto 240d one)


From my understanding, put simply, you need 4" lopped off of a manual 240 front driveshaft in order to make the swap. Which means the front shaft needs to be ~19.5", eh?

If i have access to a 300CD driveshaft, that had the 4spd swapped in, Would the front driveshaft work as long as i balanced it to my rear section?

Basically my question is- on a w123, what dictates front shaft length and what dictates rear shaft length?

From my understanding- and someone correct me if im wrong *please*-
Front shaft is dictated by engine/trans combo,
Rear shaft is dictated by wheelbase


IF that is correct, then that manual swapped 300CD shaft should work in my 1983 300D sedan, correct?

Seller claims it is ~20.5", i forgot where he said he measured from, but per needing a 19.5" driveshaft, that sounds right?

Here is the shaft- anyone able to decipher this via paint code?

What have you guys done for this situation? I, unfortunately, don't have any excellent driveshaft shops nearby.

Thanks a bunch, in advance

https://live.staticflickr.com/65535/...cce66d36_c.jpg

OK, I can make a few comments. First all rear driveshafts on sedans and wagons are the same. Coupe has 2" or so less overall length. Front driveshaft is longer on the 240 because the engine sits with its front in same position as the 300. 4" sounds about right. That is the length added for another cylinder. I will take a stab at front ds length and say that the automatic is longer than the 4 speed stick and the 5 speed is longest of all. l think also that the iron trans is different in length from the aluminum one. One of the DS is about 1/2" to 3/4" longer than the other but it can be used without problem as the slip spline absorbs that much difference.....at least we had none when putting the five speed in a 123.

Your trans should be an aluminum case which means it's a Getrag, the same trans I run in Mutt the Race Truck. I stripped it out of an "83 240D just like you did, taking the whole trans, shifter assembly, clutch slave, etc. though I'm used an S-10 clutch master cylinder. I'm no help on the driveshaft length as I went with a Jags That Run adaptor and had a regular, US-style shaft made by a local shop which has worked well up to (so far) 136.2 MPH.



If all else fails bolt the whole deal in place and measure the length you'll need and either buy the one shown if it meets the length needed or have one of yours cut to fit. Most drive shaft shops can handle this easily. As long as it's "clocked" correctly there is no black magic in this.



Dan