Are gas & diesel transmissions exchangable?
 

I am a new owner of a 1982 300d (automatic tranny) with 129K miles on it and have been reading the posts here. It runs great and starts without plugging it in down to 0 Degrees F. It is a little slower than I thought it would be in the acceleration but I have read some very good posts about tweaking it out - mostly cleanse and adjust. I also have a 99 Jetta turbo diesel that has really good pickup and go that I am using for reference. I have the usual problems of sticky sun roof, engine dieseling after shut off (continuing to run), weird climate heat and cruise control. I will be playing around with the vacuum system and tweaking it to perfection in short order as per the forums suggestions. One thing that I am interested in finding out about is whether or not an automatic transmission from a gas Mercedes will mate up to the diesel engine. There is a wrecked 77 gas Mercedes in the local junkyard (front end hit) that has some good items in it and I was thinking of picking up the tranny in case mine goes out. Any of you serious gearheads have the answer for me?

They are basically the same, but I suspect you will not want to use the gas one. The V8 engines used a three speed for some time, don't know about the 77/116 -- if it is a w115 you are ok for fit.

Gear ratios are different, they start in first gear, making it hard to hold the diesel against the engine at stoplights, and may not hold up in service.

I'd stick with a diesel tranny.

Peter

Peter,

Try a 1999 E300 Turbodiesel. I'm sure you would agree it is faster than the 1987. The torque is awesome and HP is also strong. The car pulls hard and is, IMHO, better than a gas car. Diesel fuel also just hit $0.99/gal in NJ. That and 30+MPG makes for a great package. I had a 1991 E300 2.5 turbo which I enjoyed. The 1999 defines a whole new level.

Enjoy,

Ken
'99 E300 Turbodiesel (69k)
'98 ML320 (wish it was a 270CDI)

I've heard the new direct injection diesels were something! Too bad they are out of my price range for the next ten years or so! Most people, apparently, cannot tell they are diesels once running!

I got 34 mpg on the last highway trip I made in the 87, including quite a bit of winding country road and some in-town driving.

Peter

Thanks for the feedback!
 

I won't bother with the gas tranny, based on feedback I got here and another place on the internet. Looks like too many problems could ensue. Anybody need a tranny out of a 123 style gasser email me and I will pass the message along to the guy that owns the 77.