He HAS standards??? ;-)

Shifting Rod Modification
 

OK, it's been a while since I've made any progress on Marlene's transmission conversion. Lots of other things competing for my time right now. However, I was able to get started on modifying the shifting rods. The rods need to be shortened 4" and the last 2" rethreaded with a 10mm x 1.5 die.

Additionally, these rods are hardened steel. A cheapo Japanese die shudders and chatters in fear while trying to cut threads in this stuff. So, after cutting the rods to length, but before threading the last two rods, I heated the blank ends to a bright orange with a torch to anneal the metal. The threading operation went significantly easier after treating the steel in this fashion.

Re: Shifting Rod Modification
 

I still had to bend them up to keep them from rubbing and clear the underside and get them to shift properly, so 4" was too much on a few of them and I had to weld one up.

BTW, I pulled a 4-speed like yours yesterday from a 240 with 105k miles. Got all the other parts too. Might replace mine with this one and sell the kit to someone here.

Re: Re: Shifting Rod Modification
 

Weird. I'm kind of surprised to hear about the mods yours have needed because so far, my rods look like they're going to work fine w/o any bending or welding. I am a wee bit concerned about there being enough clearance between the driveshaft and the shifting arms where they exit the hump.

BTW-Thrash just called and the driveshaft is ready. I'll try and get down to San Antonio tomorrow morning to grab it.

Re: Re: Re: Shifting Rod Modification
 

Could be the different tranny's. This one has the upside down reverse arm and the arms are all longer (shifter arms) than on the older cast-iron tranny.

Randy,

How's the conversion coming?

Went to the yard on Wed and pulled a tranny like yours. Here's pics of the two types compared (levers are off the new style):

http://home.comcast.net/~tomj/images/trans5.JPG

http://home.comcast.net/~tomj/images/trans6.JPG

One thing I forgot to get was the adapter plate for this style tranny. Rats!!! Will have to head out this week and see if it's still there. Also got the shifter, pedal assy, etc. so now I'm ready for the next 123 to throw a conversion in (shouldn't take me more than a few days at this point.)

BTW, don't remember if I gave you this info yet or not, but here's the wiring for the 4 pin conn off a 1984:

Blk/Yel = Reverse light

Gry/Yel = Reverse light

Purp = Park/NSS

Purp/Wht = Park/NSS

They sure look pretty different, any clue on technical perticulars?

Didn't make any progress this weekend ...on Sat, I went down to the Alamo city to watch Thing Two play in a VB tourney and spent the day Sunday on SWMBO's list and crating an outboard that I sold on eBay. BTW, thanks for the wiring pointers.

I have at least two uninterrupted evenings to work on her this week so I'm pretty sure I can get things rolling by Friday.


FWIW, Thrash did a knock-out job on that driveshaft. I'll post pictures ASAP.

115 -> 123 Manual Transmissions
 

Just want to get this in the knowledge base:

What we're calling the "Early" model manual transmission is (at least externally - it's two pieces:an aluminum bellhousing and cast iron gearbox ) the same transmission that is installed manual transmissioned W115 chassis ie: 1975 240D

What we call "late' transmissions are a 'one-piece' aluminum casting.

I have not found any information regarding the internal gear ratios on any of these transmissions.

Earlier diesels (220) may also have the same gear box too.

Good, the people I trusted to get it done right did the crappiest job you could imagine and charged $150 for it!

Need to get the address of those people so I can have them do two other shafts I have sitting here.

BTW, LMK what the final dims were on it. I had mine done to 54cm I believe, and it's a bit tight.

Driveshaft modifications for manual transmission
 

Here's the modified driveshaft. Since the rear part of the 123 driveshaft is fundamentally the same on all models, I altered only the front section. In this case, I used the front piece from the donor 240D and had it shortened to 19.75" measured from the front face of the flex disk 'spider' to the back edge of the fixed hex flats on the shaft.

Here's where I measured to on the donor shaft (the painted-on arrow is to align the two shafts for balancing). When everything is in place on the car, there's less than an inch of the splines exposed and the rubber boot protects almost all of that:

Here's the witness mark on the flywheel. It must be aligned with a similar mark on the crankshaft.

Flywheel installed on crank. The witness marks are tough to find...liberal application of Brakleen and vigorous wiping with rags revealed them. On this crank, there's one on the flange and a corresponding one in the relief for the pilot bearing.

Clutch in place.

You really need a clutch alignment tool for this. I tried to eyeball the alignment of the clutch disk but apparently couldn't get close enough to make the transmission mate up and everything fit together.

So, I searched the AutoZone site for a cheapo, plastic alignment tool and, amazingly enough, came up with this number Motormite PN14522 as the tool for Mercedes-Benz manual clutches from 75-85.

It turns out that this part number is the same as the one used for aligning Chevy S10 clutches so maybe, just maybe, there's snowball's chance that I can get this must have tool.