Manual Transmission Differences

[George Des]

I noticed that the gasket kits for the 230/250SL manual box is listed differently from that for the 280SL. Anyone know what the differences are in these boxes. Are there different numbers?  Are there any differences in the fitting of the boxes? I've got a 4 speed box--nto sure what this one came from but it does have the proper top cover with the canted attachment for the shift tube-- that I plan on installing temporarily while I go through my ZF box. I know the front driveshaft and the linkages for the ZF will need to be swapped out--I have the linkages but not the driveshaft yet-- to do this but I also wanted to go through the 4 speed box before I put it in.

George Des

[Benz Dr.]

Most of the parts are the same but there are a few differences as well. They all use the same bearings including a 190SL box which is very similar to a 230SL box. The 190 only has four screws holding the top cover down while the six cylinderr boxes have six screws.

One of the main differences is how the bell housing is attached to the front of the box. On the 230 there are four large screws with nuts that hold everything together. On the 280 SL the screws are threaded directly into the front of the box. The two top screws at the back of the box on a 280 ( that hold the top cover down ) have larger pins for the larger bushings that go on the stabilizer rods but other than that I think the top covers are the same.

I haven't had a look at 280SL gear box in a while but I will add more to this thread soon because I'm about to pull one out of my parts car. I know there are other small changes but until I see it I won't be able to say for sure.

[George Des]

Thanks, Dan. Sounds like there shouldn't be any issues then with mating any of them to the engine or with the clutch? Is that correct?

George

[ja17]

Yes, most versions of the era should bolt up to the engine.  I remember some differences in the throw- out bearing and its mounting tube diameter also depending on the year. Watch for minor variations in the hydraulics and their mountings (no big issues).  I have switched four and six bolt top covers on both types  over the years and never had any issues. A lot of times, just switching out the two-shift-rod top cover off a sedan box with the singl-shift-rod top cover off an SL box will make it ready to install in the SL depending on year.  Check your "Technical Data Manual"  or your BBB for differences in gear ratios for different boxes.  Fourth gear (final drive)is always the same and is one to one. There are several version single shift rod top covers however. The shift rod is straight on some and it "goose-necks" down on others. for tunnel clearance most likely.

Some of the internal parts of these "top cover boxes" are becoming very expensive or NLA. I always save good sedan boxes for spare parts. Many parts in a "top cover sedan box" are the same.

The main shaft bearings are somewhat standard and are still available from local sources and are very reasonable.

[George Des]

Thanks, Joe and Dan. The number on the 4 speed box I have is 111 281 05 01. It also has a stamping 3 5 6--I assume this is Mar 5, 1966. The bell housing is 111 250 21 05. Not sure what this came off but it does have the top cover with the goose neck linkage attaching shaft.


George Des

[Benz Dr.]

I think it would come from a sedan, coupe, or SL from the same time frame. Many sedans had column shift and later cars had the shifters on the side of the box so it narrows it down to certains cars from the 60's and early 70's.