You know, that's just what I was thinking too, but didn't want to say anything till I tried it. Since I have a few 4-speeds apart right now, that's an easy thing to try. Will LYK if the frankentranny is successful.

BTW, the bottom pic is just a top view of the 5-speed, no doctoring. Here's the full-size:

http://home.comcast.net/~dehlta/images/5speed3.JPG

Dude,
You still have the image reversed...look at the shift arms and clutch cylinder.

Man, oh man, what an überkalt projekt!!! It will be interesting to see how that FrankenTranny works out. IIRC, FSM warns of the ususal dire consequences about swapping parts from the various 3-piece boxes but I'll bet all those from one-piece boxes will swap just fine.

Does anyone know the approximate torque capacity of the 190E / 190D 5-speeds? Are they essentially the same as the 300E manual trans?

Ted,
I've never seen published torque specs for any of the MBZ trannys. IMHO, the units in my fleet appear to be extremely robust in comparison to the 3-speed and 4-speed Muncies of my youth.

DOH!!

Had it mirror imaged when I saved, fixed now!

I never would have thought to try that. Definitely get back to us if you get frankentranny to come alive.

Am halfway through teardown on the 5 speed and it actually looks doable so far!

Will post pics and info later (have to teach tomorrow and haven't even started my curriculi.)

Bad news!

No way on this gut swap.

The case on the 124 5 speed is 1.2mm longer than the 123 4 speed and it's not just the end (or I'd machine a plate to compensate), it's the distance from the front bearing to the shift shafts that's just a little stretched.

Thought about going in and machining the case inside to compensate, but there's another problem....

There is a reverse idler that mounts on a shaft in the case. On a 123 4 speed that area is a hollow web section, on this 5 speed, it's solid and machined at half-moon to accomodate the shaft mount.

This still could be overcome with a machined block welded in and then fly cut on the mill for the half moon, then drilled through for the mount blot.

But....., it's really not worth it at this point. I'll rebuild this tranny as-is (new synchro's, springs, seals, etc.) and sell it for enough to buy a 123 5 speed...., or not????

Here's a case comparison from outside, VERY close, but no s*x toy..., uh...., I mean cigar:

http://home.comcast.net/~dehlta/images/cases7.JPG

Here's an empty case comparison:

http://home.comcast.net/~dehlta/images/compare2.JPG

Here's a close-up of the webbed hollow area on the 123 tranny that is solid on the 124 tranny:

http://home.comcast.net/~dehlta/images/123_case.JPG

So..., if I feel REAL energetic, I'll do the case mods on the 123 and post, but it's likely I'll just rebuild the trannies and save till someone breaks theirs or whatever.

Too bad frankentranny didn't work out. Thanks for the info.

This might be a stupid question, but what if you leave all the 4 speed guts in the 123 tranny instead of trying to bring over the guts from the 190 tranny. Will the 5th gear section of the 190 tranny then bolt up to the back? I'm refering to the seperate box on the end of the 5 speed tranny. I know what it looks like in my head, but it's hard to articulate. :)

I know what you're saying, but the 5 speed stuff takes the place of the reverse system on the 123, that's why it's added off to the side in the 124 case, so I could possibly do that, but wouldn't have reverse gear.

If I could find a 5 speed that is a divorced unit, I could maybe adapt the bell housing off the older 4 speed to it?

TomJ,
It's a cryin' shame that case swap won't work. Thanks for giving it a try anyway!

R

Got it... different gate pattern, etc.

Regarding the divorced unit, that is essentially what I am doing. But it certainly isn't a bolt-in swap. The main problem is that the MB tranny is very narrow by the slave cylinder, and most 5 speed trannys are too wide. I am using a hydraulic throwout bearing in my swap to circumvent this issue. But using MB parts that bolt together is always preferable.

Yeah, like just using a MB 5 speed made for the 123!

*grin* Trust me, I looked. If I could find diesel 5 speed for under $500 I'd have snagged it up. But most of the ones I see on this side of the pond fetch a premium. When all is said and done, I'll have $500 in the entire swap. We'll see how it turns out.