Hello
can anyone help me with finding a 5-speed manual setup for a 1985 300TDT?
Thank you

Best bet is to try getting one from a 190E...and you'll also need clutch pedals, driveshaft, flywheel, and other misc items. Or if you're creative and can machine stuff, you can mate up a different 5-speed from a different car with an adapter plate, and a bit of machining. Anything can be done with enough money and machining.

Unless there's been some new R&D, the Getrag 717.400 is the only known drop in manual 5 speed out there for the diesel family of OM616/OM617 engines. Hop over to S T D dot.com and there's threads and threads of folks trying this or that, and so far I have not really seen anything which really works .... unless you have Jay Leno's budget and even then I still have not seen it. Post away some links of a OM616/617 with a 5-speed OTHER THAN Getrag 717.400. Folks would like to see it.

You don't need Leno's budget....you just need to pay a machine shop to fabricate an adapter plate and/or make an adapter for the output shaft of the transmission. Cost = less than $500 for this. Then get the driveshaft modified at a driveshaft shop. Cost = less than $500. If you can machine this stuff yourself, then the cost is only materials.

I have a friend who put a 5-speed chevy transmission into a w123 with a stock Mercedes engine...only problem he had was the shifter sits a bit more forward than stock...but that can be corrected if you make a thicker adapter plate.

As noted above, and throughout the various forums, the only known drop in 5 speed manual tranny is the Getrag 717.400.

I still have not seen any links to folks who have used other 5 speed manual transmissions for the OM616/OM617 family of diesel engines. Folks talk about using this or that, machining this or that, but all of those mod's have not really materialized into an effective workaround. Plus, most machine shops are in the ballpark of $75 to $85 bucks an hour. That does not include R&D, CAD, et cet. The aluminum plate alone (stock material) will cost you $100's of dollars if you can find one. Good luck on that. That is, finding the plate at a scrap yard.

Pretty sure it will cost more than $1,000.00, plus the costs of the parts to begin with. If one cannot afford the $2K or so investment for the Getrag set-up, why would someone invest a lot more than that for a R&D project not to mention a lot of wrenching and wrenching skills.