240D 4-speed manual swap in 300CD - PeachParts Mercedes-Benz Forum

gavin_leslie · #1 11-30-2007, 03:01 PM

Original thread is here.. Transmission issue: No forward drive gears in 78 300CD

The long and the short...the 722.118 automatic failed(failure mode still undetermined). Car has near 350k on the chassis, engine fully rebuilt in 1995. car was purchased for $2200 by the GF and a fair amount of maintainance work done by yours truly.

The options to get the car going were..remanufactured transmission at $1400-1600 with installation @ $6-800. Install remanned transmission myself. Refurbish transmission myself with parts ($6-800?) and install......look for different car alltogether.

The GF has no other mode of transportation so time was somewhat of the essence. Others have said that rebuilding an automatic is not rocket surgery, but is challenging and time consuming. Never having worked with an auto transmission before my comfort level was/is low. With time I could figure things out, but....Franky speaking, with a lack of time, manuals and facilities there needed to be a faster option. Compounding this was the initial cost of the car. It was pretty cheap, at that price there was serious thought to just how much effort we really wanted to put into a 30yr old car...no matter how much affinity we felt for the old girl. The answer had to be quick, cost effective and a real effective solution.

While searching on information for repairing the auto trans I came across this.. http://www.peachparts.com/shopforum/diesel-discussion/88699-auto-manual-transmission-conversion-has-begun.html#post581868 which lead to this.. http://www.peachparts.com/shopforum/diesel-discussion/146636-w123-240d-engine-swap-om617-300d-manual-transmission-swap.html#post1105195

With a 50% off sale post thanksgiving at the Junkyards this seemed like the answer I needed.

I do have questions with the swap however that I havent seen mentioned(I admit I may have missed them however)

Copied and pasted from Transmission issue: No forward drive gears in 78 300CD

Quote:

Originally Posted by gavin_leslie

I have been going through the usual suspects http://www.peachparts.com/shopforum/showthread.php?p=1105195#post1105195 and nothing seems too out of the order but I did have some questions.

-There was a mention of different(?) pilot bearings. Was this an issue for your conversion?

-The shift linkages need to be shortened and threaded. I notice the threads are rolled(extruded) threads. Was this an issue with thread engagement as the existing threads are thicker than the actual shaft.

-whats the installation order of the shift rods? I, er....forgot to label what went where in my haste to remove the trans in the yards

(hey, it was 50% off, I was swept up in the tide of savings)

-where are these indexing marks I keep hearing about? I must be blind because I havent seen any on the flywheel or the driveshaft.(but does this really matter since they will be on a different car and be balanced(driveshaft) and not(5-cylinder engine/4cyl flywheel))

-I hear that the 5-cyl engine is inherently unbalanced because of the odd firing sequence. What is the real day to day reality of vibration from the engine/. Also, with regards to bearing life, has there been any indication that the additional vibrations from the engine have prematurely worn crankshaft/main bearings?

-Wiring. I assume that brake lights/reverse lights will be a plug in affair..what else?

The driveshaft is at the workshop to be shortened and balanced. Just a bit of measuring of the transmission lengths (6.125" difference) and "add" that to the length of the driveshaft (stock stubby was 13.375"). Total new stubby length will be 19.5".

Any additional pointers would be a help.

Gavin

winmutt · #2 11-30-2007, 04:18 PM

Pilot bearing is only an issue on the 85s (smaller crank snout).

Shift rods are going to be diff in ever install practially. You have what looks like an aluminum case version, mine is cast iron with different arms etc.

The flywheel should be neutral, I run a 200D version in my car no problems.

You will need to short the neutral safety switch and figure out how to rewire the backup light switch to the shifter (vs trans on ayutos)

the DS can have up to ~1.5" or so of exposed splines at the middle sections, so you might want to make it a little shorter than you expect it to be.

What is the casing number on that trans? Totally different setup on the arms than mine. My arms have an S curve (to provide a little more clearance) and point up. (IIRC I had to reposition them up for the fit).

#3 11-30-2007, 05:24 PM

That was very smart of them to put the paint marks on the wear surfaces.

pawoSD · #4 11-30-2007, 05:46 PM

Quote:

Originally Posted by ForcedInduction

That was very smart of them to put the paint marks on the wear surfaces.

Nothing a dose of brake cleaner won't get off!

t walgamuth · #5 11-30-2007, 06:19 PM

When you remove the flywheel from your engine you need to mark its location. Then take it to a machine shop and see if it is neutrally balanced. if it is not the new flywheel will need to be match balanced to it. While you are at it you should get the new flywheel checked also for neutral balancing. If both are neutrally balanced you are golden.

The odds are you will be fine, but some of the 123 engines have flywheels which are balanced with a crank that is a little too far out of balance to be neutrally balanced by itself.

IN any case the new flywheel needs to match the needs of your engine's crank. If you happen to have one of the non neutrally balanced cranks, if you bolt on the flywheel and it is wrong it will shake your eye teeth out and possibly ruin the bearings in the crank.

Assuming all is matched up correctly, the natural 5 cylinder hopping will become a noticable quiver as you accelerate and pass through the rpm at which it occurs. Hardly noticable and not a problem.

It is a very nice, satisfactory conversion.

Tom W

Stevo · #6 11-30-2007, 08:06 PM

If you cant find a mark, its ready to "plug and play", At least thats the criteria I use.

There should be NO mark on the crank OR F/W,

t walgamuth · #7 11-30-2007, 08:15 PM

The mark on the fw of my 280 was so nearly invisible that my favorite machinist couldn't see it at all, but his sharp eyed young son did, finally. It looked like a halogram of an omega, kindof.

Tom W

Stevo · #8 11-30-2007, 08:29 PM

Oh ya, those marks are hard too see, I use fine emery cloth too look for them. The 79 240D I still have had marks on crank and F/W, I should say the 80 engine I rebuilt for it, did.
I haven't seen "marks" since.

240d jeep · #9 11-30-2007, 09:58 PM

I am running a 220d Flywheel on a 240D engine and I didnt even look for marks. If there is no pin or anything and the bolt pattern is round then it will work! I used to think this was a big deal but I built a 400 chevy a few years back with parts from around the shop (no money) had 3 diffrent kinds of pistons and 2 were 70 grams heaver than the rest and had a rebalanced flywheel from a guy that said it would work (350 with a weight) ran 50k miles no problems no vibrations turned 5500 a lot never died!

t walgamuth · #10 11-30-2007, 10:31 PM

Well, that is what I used to think too. I did several without consideration of balance and was fine.

Until we did my 280e. It was balanced with the crank for sure. It is too much work to ignore the possibility that you have the one in four or five that is balanced with the crank. I mean too much work to tear it all down if you guess wrong.

The FSM says to assume they are balanced with the crank.

Tom W

gavin_leslie · #11 11-30-2007, 11:14 PM

winmutt, t walgamuth...thanks for the info. I was hoping to have everything buttoned up this weekend, but I suppose delaying things just a bit longer to ensure that things are in balance is a good thing.

I recall a thread where there was a listing of that wires do what on the auto safety switch. Ill have to track that down again.

ForcedInduction...Its a thing that they do here at the yards. They take a paint pen and scribble something unintelligable on it just in case you wish to return it, though Im not sure why you would do that. In any case, I saw then going for the flywheel surfaces and gritted my teeth a bit...nothing that cant be taken care of with a rag and brake parts cleaner.

Im pleased to hear that there seems to be a decent group of people who have done this to success. My main concern about doing this was(especially in light of possible added vibration) was a reduction in longevity/durability. The last thing that I wish to do is wreck the cars propensity for reliability.

Driveshaft picked up today. Shortened and balanced with new guide pin bushings. The paint has barely dried on it.

Gavin

Austin85 · #12 11-30-2007, 11:28 PM

As I have written here I have a 4spd from a 240 that I wanted to have put into my 82 300CD, (which BTW slips in 2nd and now will eventually need a rebuild, I am told.)

I got it fom Bruce K. and my ex- indie told me he would do the swap for around 500., so I purchased it with this in mind & budget.

When I got it my EX- Indie tells me he never said 500. He says 1,500

I have recently asked another very experienced shop that does these type of mods all the time, and he also said 1500 + possible other ancillary costs.

I do not have the room or experience mechanically to do it myself, so can anyone tell me if this 1,500 range is reasonable or high.......or low. for a good job.

Thanks,
AA

t walgamuth · #13 12-01-2007, 12:25 AM

I think I paid my indie about $700 and that included 175 for lengthening the driveshaft (or was it shortening?). Anyway they made a new ds with my old ends.

Tom W

gavin_leslie · #14 12-01-2007, 03:10 AM

managed to get half of the stuff I ordered in preparation for the transplant.

I took a guess at the shift linkage bushings and lucked out(theres a lot of bushings to choose from), new pilot bearing, driveshaft coupler boot thingie and a new shift knob.

Im not sure what the deal was, but there were four 240Ds in the local yards and all of them were missing their shift knobs. Is this a rare item that fetches a kings ransom on the black market? I was lucky it seems that the 240 I was working on still had the shift mechanism itself. All the other 240s had theirs swiped...not the transmissions mind you, just the shifters and shift linkages.

The other half of the parts I ordered were two rebuild kits for the clutch master and slave cylinders. They should be arriving at the start of the week.

Yeah, I think this may turn out pretty well indeed.

Gavin

t walgamuth · #15 12-01-2007, 08:42 AM

The shifters never really wear out but they have a bushing that does. It is a bit of a job to change it. Folks who don't realize it is a $2 part might just get a new shifter. The knobs do sometimes fracture and a new one costs over $40. It looks like you are nearly ready.

Good luck.

On a car this old it is a hugley better deal running the unbreakable stick tranny vs trying to get an old automatic right. The automatics are about bulletproof but if they don't get the fluid and filters changed religeosly per the book they will begin to malfunction before 100k miles.

Tom W