Will a MB 4-speed manual transmission from a 1973 220 fit into an 85 300CD?? - Page 2 - PeachParts Mercedes-Benz Forum

Tanksowner · #16 07-01-2012, 08:16 PM

An automatic wouldn't last as long as a manual in most cases, but if it isn't giving you problems, don't change it. That version of the 722 transmission is pretty reliable, and makes for a great driving experience with the 2.88 diff. Only change it to a manual if it's truly what you want to do, everyone on here will give you differing opinions. Me personally, I would leave it the way it is.

charmalu · #17 07-02-2012, 02:13 AM

Amazing reading through some of these posts recommending to stay with or going back to an automatic. there has been a lot of 4-spd swaps since I signed up in 07, and a bunch years before.

Now maybe some of you are just a shiftless bunch

.

I swapped the 85 to a 4 spd, and picked up 3 mpg. out on the Hwy I was seeing 30 -31, never came close with the auto. I have the 2:88 Diff and works ok, but maybe a 3:07 would be better is some situations.

I don`t have the problem with the turbo winding down between shifts, maybe because of driving bigger trucks with 10 and 13 spd trans, also smaller trucks with a 4 or 5 spd and 2 spd Diff. just about all these were turbo engines. so I do not see what the big deal is with a manual trans behind a MB diesel engine with a turbo.

Either you like it, or you don`t. I prefere to be a little of the shifty side.

Charlie

charmalu · #18 07-02-2012, 02:16 AM

Here is a link from Super Turbo Diesel showing all the various manual transmissions,

Manual Transmission information

Charlie

Air&Road · #19 07-02-2012, 08:16 AM

You will have to use the engine adapter that goes with the transmission. It will bolt to the engine with four bolts and mate the transmission.

That transmission is NOT as strong as the later manuals that were used in the 123 diesels.

edge · #20 07-02-2012, 09:52 AM

I had a bead on a 4-speed manual transmission from a 1973 220 for only $200 but couldn't source it. Apparently it was an old listing and may have already sold.

edge · #21 07-03-2012, 10:04 AM

Finally got a call from the seller. Now i really have to access feasibility to swap into my '85 300CD. How involved are the mods to get this transmission in? My 722.3 drive ratios are:

I. 3.65
II. 2.41
III. 1.44
IV.1.00
Reverse 5.14
Final Dive 2.88 differential

Thanks, all.

Air&Road · #22 07-03-2012, 01:08 PM

You might have already said, but is this going in a car that already has a manual transmission?

Benzkid_300D · #23 07-03-2012, 01:13 PM

Quote:

Originally Posted by Air&Road

You might have already said, but is this going in a car that already has a manual transmission?

No it has the 722.3 trans... Which is an automatic

And I like the idea of having a manual... Wouldn't have to worry about the vacuum problems and the famous B2 going bad

JB3 · #24 07-03-2012, 04:22 PM

Quote:

Originally Posted by lovedieselsd

I've had an '85 300cd that some retard installed a 240d trans into. drives horrible. don't do it. gears are too short, you gain nothing. there's a reason mercedes never put manuals behind a turbo charged engine. every time you shift, the turbo has to build up pressure again, which isn't the case with an automatic as they shift faster. from a 240d it's a simple bolt in though, if you find a donor. and then a 5-speed and maybe a longer geared diff and you'd have something.
I yanked that junk out and put an auto trans back in, so much better.

Final drive on both the automatic and manual are 1-1. For me, driving was quite a bit improved with a stick behind a turbo motor. This is the first post ive ever heard of someone complaining, anyone who's done this pretty much enjoys it.

the 85 300CD will have the 2.88 diff stock, so it would have the fastest final gear cruising speed, but slightly lower acceleration.

JB3 · #25 07-03-2012, 04:35 PM

Quote:

Originally Posted by edge

Finally got a call from the seller. Now i really have to access feasibility to swap into my '85 300CD. How involved are the mods to get this transmission in? My 722.3 drive ratios are:

I. 3.65
II. 2.41
III. 1.44
IV.1.00
Reverse 5.14
Final Dive 2.88 differential

Thanks, all.

there are some mods, but not terrible. The gearbox will bolt up, the manual and auto both fit the backing plates.

You will have to modify the shifter rods, forward driveshaft section, and probably the transmission mount on the coupe. (on the sedans you can use a 240 auto trans crossmember, but not sure on the coupe.)

This is a fun, and entertaining swap to do.

you will be installing a new pedal assembly, shifter assembly, ect.

Make sure to source the shifter and linkage rods with the transmission. If you don't have a 4-speed shifter and rods to go with that 4-speed gearbox, you have to find a set, which can be irritating and/or difficult.

From a donor car (115 or 123) you need-

transmission
3 shift linkage rods
shifter assembly
flywheel
clutch fork

From a donor car (specifically 123) you need-

pedal assembly
trans mount cross member

you should buy new-

Clutch master
clutch slave
clutch
pressure plate
pilot bearing
release bearing
clutch master and slave connecting lines (you can make this from brake line though)
shift linkage bushings
transmission rubber mount
(depending on condition) drive shaft flex discs and carrier bearing
12 flywheel bolts specific to the manual flywheel. (not cheap)

You will have to custom modify-

shift linkage bars (probably shorten them after custom measurement)
Forward driveshaft, and then balance (probably shortened after measurement)
probably the transmission mount crossmember to match bolt holes

expect to spend some hundreds of dollars collecting all the parts, and modifying and or balancing the driveshaft. Its worth it to do the swap from the fun perspective, but you are probably looking at 5-600 dollars in used and new parts alone. FYI. Plus, maybe 150-200 on the driveshaft. (rods can be cut off and rethreaded, easy)

JB3 · #26 07-03-2012, 04:46 PM

Quote:

Originally Posted by charmalu

Here is a link from Super Turbo Diesel showing all the various manual transmissions,

Manual Transmission information

Charlie

I 2nd checking out this link. you will see what a slope back iron 4-speed like from a 115 looks like, vs a 1 piece aluminum gearbox.

Also information on ratios. Check the EPC as well. If the seller can give you an idea of the car the gearbox came out of, you can get an idea of the ratios of 1-3. 4 will be 1-1.

apart from the nonsense about the car being slower with a manual, its just that, nonsense. Top speed will be effectively exactly the same, the rest it up to your shifting.

The turbo spooling event makes it even more fun to drive IMO. Its like a n/a 240 for approximately 2-3 seconds, and then the turbo spools, and the car takes off.

it takes about 5 seconds to learn how to compensate for this in throttle position, and there are plenty of things you can do to change that as well.
Like several of us have said, there are very few people who have converted their car to manual who have regretted it. The above post is the first I ever hear of anyone complaining.

There are lots of build threads, most everything will be the same except for some dimensional tolerances based on the wheelbase of the coupe vs the sedans and wagons

whunter · #27 09-01-2013, 12:13 AM

because I am doing a conversion now.

1985 300D automatic to manual transmission, using 220D (vin# 11511010041125) parts.

.