Hi all,
I just recently learned that MB sold the W124 in Europe with a 5-speed automatic tranny (722.5xx). I was also told that the 300SL/SL320 5-speed will work in the 124, with either a custom driveshaft, or (I presume) the Euro 124/5sp shaft. Has anyone heard of this swap being done in the USA? Any known "gotchas" involved? The 5-speed stick swap is very complex and nearly impossible without a donor car (i.e., a donor that comes with the manual trans & all the required parts!), but the 5-speed auto should (?) be simpler. And I don't really want a manual trans in this car.
The advantage would be allowing a lower axle ratio (change my stock 2.65 to a 3.07 LSD from a 16V) for very strong off-the-line power, and around town it should be snappier in general, if kept in 3rd or 4th gear. The 5th gear is a 0.75 overdrive which would end up being a little *taller* than the stock final drive, for even nicer freeway cruising, and a little higher top speed (about 140mph instead of stock/rated 129mph, assuming there is power to push it up there.) The 5sp shift gate, etc, are all parts that can come from Europe. The only downside I've seen so far is that used 5sp trannies are expensive! Probably $1500+... ouch ... plus the diff. But the performance should be impressive, the LSD will pretty much be a requirement along with fat tires to make the thing hook up off the line. (buwaahahahahaaa!)
The gear ratios for the 4sp and 5sp are in this PDF file:
http://www.meimann.com/docs/mercedes/Tranny_ratios.pdf
Side note: The donor tranny would have to come from a gas engine. Can the valve body be tweaked (different springs, etc) to get the shift quality correct in a diesel? Or will it shift OK "as-is"? IIRC, the M104 makes about as much torque as the OM603 so there should not be a strength/reliability issue.
Regards,