4 speed automatic overdrive transmission Conversion into a 1975 mercedes 450 SEL

[aluminum]

My Car is a 1975 Mercedes 450 SEL sedan

Can it be done ? I want to convert My 3 speed Automatic transmission to a 4 Speed automatic overdrive transmission

Mercedes 560 SEL has a 4 speed automatic overdrive transmission .
well this bolt up to a 1975 450 Motor ?.
anyone done this ?
Any input appreciated . Perhaps a Overdrive Unit can be attached to my 3 Speed unit already in my car ?

What is the Overdrive % on a Mercedes 560 SEL has a 4 speed automatic overdrive transmission ? 30 % or 40% I know most are 30 % but some overdrives are 40 % . If anyone knows
what Overdrive unit well work ?

[Stretch]

Both engines are of the M117 variety to I would expect that a 722.3 transmission from the W126 would bolt up to your engine.

I don't know if the 3 speed 722.1 is shorter than the 4 speed 722.3 transmission though. There could be propshaft length problems.

The main thing to mention, however, is that the 4 speed 722.3 transmissions do not have an "overdrive" gear. Top gear is a 1:1 ratio.

If you want an "overdrive" transmission you need to be looking at 722.5 transmissions and newer - but then you move away from pure hydro-mechanical units into the realms of electrickery...

...a separate overdrive unit could be fitted but I think you'd probably find that to be more expensive than a replacement gearbox.

If you are trying to get better fuel economy I'd start learning about Mega-squirt rather than fooling about with gearboxes.

[aluminum]

Originally Posted by Stretch

Both engines are of the M117 variety to I would expect that a 722.3 transmission from the W126 would bolt up to your engine.

I don't know if the 3 speed 722.1 is shorter than the 4 speed 722.3 transmission though. There could be propshaft length problems.

The main thing to mention, however, is that the 4 speed 722.3 transmissions do not have an "overdrive" gear. Top gear is a 1:1 ratio.

If you want an "overdrive" transmission you need to be looking at 722.5 transmissions and newer - but then you move away from pure hydro-mechanical units into the realms of electrickery...

...a separate overdrive unit could be fitted but I think you'd probably find that to be more expensive than a replacement gearbox.

If you are trying to get better fuel economy I'd start learning about Mega-squirt rather than fooling about with gearboxes.

Thanks for reply
Mega-squirt however is far to much money and by far to much work as I understand it . I have reviewed many Mega-squirt installs and they seem very costly and time consuming so therefore totally counterproductive . not spend money and wait 5 years to get it back lol .
if a Overdrive Tranny Fits to the Block I can get a used one and cut the drive line to fit as they are longer . However if they are driven by some brain rather then some simple Electrical Solenoid or the like perhaps it not worth it . the whole car and It's a great one only cost $1,500 and I have only put in $ 250 to make it run perfect . However the gearing is very poor without overdrive . My Guess is that Mercedes made the Overdrive far from simple to operate because when it comes to Electrical most often they just went crazy , like the Curse Control for example what a joke . All the German cars are like that it seems to me . Great Mechanical but junk Electrical .
with Mega-squirt for example ? what's a easy Trigger wheel ? My Idea is to take one from some Euro Ford and spot weld it to the front Pulley . a Sabb TPS some GM warm wide band O2 Sender and some working 19 Lb injectors that just bolt in with no o ring extra cutting , all that for about $15 or less .
However the cheapest Mega / is what lol some huge amount ? $600 come on I have bought many cars for $300 ? . Salvage yards are full of late model Mercedes and a used TRANNY is only $150 just for example if one fits i can cut a drive-line and get it balanced and welded for like $50 no prob . In fact I can weld it myself and just get it balanced .
seems like the overdrive is the way to go But only if one fits and the electrical can be adapted .
but thanks for the reply and have a great week regards

[aluminum]

Photos of a Car that would like Overdrive

[Stretch]

At the risk of sounding a bit abrupt it seems like your thinking is going round and round from mega-squirt to transmissions and back again.

Why not take a step back and define the problem with the way the car is at the moment =>

Is it using too much fuel?

Is the engine revving too high?

At the risk of loosing traffic light dommination-ability you could change the final drive ratio (differential) to get a lower revving engine at motorway speeds. If that is mostly where you drive then it might be the cheapest way of making a change.

And then there's always conversion to a different power plant => Many here would "go diesel"!

[GGR]

I don't think the 560 trans has an overdrive 4th (they have a different differential ratio though) and it won't bolt on the 450 as aluminum blocks have a different bolt pattern in the back.

As Stretch says, the simplest and cheapest way for you would be to replace the differential with a different ratio.

[DieselPaul]

No overdrives until early R129s and W140s with the 722.5 which is a 722.4 mechanical 4speed with an electronic overdrive slapped on the back which often fails and is tough to control.

722.6 is the fully electronic 5speed automatic with overdrive. It would require a stand alone controller to operate it, whipplem104 sells them/is developing one.

No W126 has an automatic overdrive.

Something I've thought about doing is adapting a GM 700R4/4L60 to a Mercedes motor. They are mechanically shifted and controlled by a cable sort of like a 722.0/2/3/4. But that would require an adapter plate.

[aluminum]

Thanks for all this Information a lot of good information here from everyone.
perhaps I can get a handle on it from this information.
I does seem somewhat unusual with the vast amounts of MB Models and so many V8 Motors that some Transmission would not fit right in to the motor with a Overdrive / but perhaps .




I think My post is quite Clear and have nothing against Mega-Squrit it a great system but to costly in my opinion . If I could buy the unit for say $100 to $300 and just need the balance of the equipment from other Cars , Most likely salvage Cars then I would consider it .

[alabbasi]

Originally Posted by Stretch

Both engines are of the M117 variety to I would expect that a 722.3 transmission from the W126 would bolt up to your engine.

The bolt pattern from a 722.0 and a 722.3 are different as the 3.5/4.5 block design is different to that of a 3.8/4.2/5.0/5.6.
Furthermore, the 722.0 is more like a 4 speed with a missing 1st gear instead of a missing 4th gear. If you notice the shift marks on your speedo, the 1,2 shift is at around 60mph. The 722.3 by contrast will start in 2nd gear unless in kick down.

If you want to increase fuel mileage and get lower RPM at highway speeds, maybe changing to a 6.9 rear end (2.65:1) would be a better option or swap the complete drive train from a 420SEL (don't bother with a 560 as it's a gas hog).

[aluminum]

Originally Posted by alabbasi

The bolt pattern from a 722.0 and a 722.3 are different as the 3.5/4.5 block design is different to that of a 3.8/4.2/5.0/5.6.
Furthermore, the 722.0 is more like a 4 speed with a missing 1st gear instead of a missing 4th gear. If you notice the shift marks on your speedo, the 1,2 shift is at around 60mph. The 722.3 by contrast will start in 2nd gear unless in kick down.

If you want to increase fuel mileage and get lower RPM at highway speeds, maybe changing to a 6.9 rear end (2.65:1) would be a better option or swap the complete drive train from a 420SEL (don't bother with a 560 as it's a gas hog).

Good Post ,
If you want to increase fuel mileage and get lower RPM at highway speeds, maybe changing to a 6.9 rear end (2.65:1)
sounds interesting not Evan sure what my 75 MB 450 Rear end is anyway ? . A guess would be about 3.50 something
Millage is not all that bad but could be better for sure

[alabbasi]

Originally Posted by aluminum

A guess would be about 3.50 something
Millage is not all that bad but could be better for sure

I think that it's 3.07:1

[Stretch]

Originally Posted by alabbasi

The bolt pattern from a 722.0 and a 722.3 are different as the 3.5/4.5 block design is different to that of a 3.8/4.2/5.0/5.6.
Furthermore, the 722.0 is more like a 4 speed with a missing 1st gear instead of a missing 4th gear. If you notice the shift marks on your speedo, the 1,2 shift is at around 60mph. The 722.3 by contrast will start in 2nd gear unless in kick down.

...

Thanks for clearing up the bolt patterns for the 3 speed transmissions. The 2nd gear start issue isn't clear for the 722.3s however - some do start in first - some don't. I still haven't figured out what the Mercedes thinking is behind all of this.

The Russian EPC gives two options for the final drive for the W116 450SEL - either 3.06 or 2.65 depending on the chassis number.

สเ๒เ๋๎ใ MERCEDES

[Frank Reiner]

Re: M117 Bell Housing Bolt Patterns

722.3 transmissions can be interchanged with 722.0 transmissions,
IF,
the top two, and in some instances, the bottom two, bolt holes are slotted to match the block locations. The two side bolt locations are unchanged.

When the M117.960 was installed in the R107 it was equipped with a 722.0. The adapter (the intermediate plate) was slightly altered to match the top bolt locations of the aluminum block. Replacement intermediate plates are supplied with slotted holes so that they may be used with both iron and alum. blocks.

Re: Final Drive Ratios

Post 1981 or 82 both W126 and R107 chassis with 3.8 and 5.0 M116/117 engines were equipped with 2.47:1 rears in a case configuration that will bolt into a W116. The change in case mounting came in 1986.

[aluminum]

Years, Model, Engine, Differential Ratio, Differential Case Size, Ring Gear Size
You need the donor speedo from the car that the diff came out of. The head is calibrated to the diff

R107
1st Generation mounting
1972-1980, 350 SL/SLC, M116, 3.46, 1.1 Liter, 185mm
1973-1980, 450 SL/SLC, M117, 2.65 / 3.06, 1.3 Liter, 210mm
1981-1985, 380 SL, M116, 2.47, 1.3 Liter, 210mm
1981-1982, 380SLC, M116, 2.47, 1.3 Liter , 210mm

W114
1968-1976, 230, M180, 3.69 / 3.92, 1.1 Liter, 185mm
1968-1972, 250, M114, 3.69 / 3.92, 1.1 Liter, 185mm
1972-1976, 250, M130, 3.69 / 3.92, 1.1 Liter, 185mm
1969-1976, 250C/CE, M130, 3.69 / 3.92, 1.1 Liter, 185mm
1972-1976, 280/E, M110, 3.69 / 3.92, 1.1 Liter, 185mm
1972-1976, 280C/CE, M110, 3.69 / 3.92, 1.1 Liter, 185mm

W115
1968โ€“1976, 200, M121, 3.92 / 4.08, 1.1 Liter, 185mm
1968โ€“1976, 200D, OM615, 3.92, 1.1 Liter, 185mm
1968โ€“1973, 220, M115, 3.92 / 4.08, 1.1 Liter, 185mm
1968โ€“1976, 220D, OM615.941, 3.92, 1.1 Liter, 185mm
1973โ€“1976, 230.4, M115, 3.69, 1.1 Liter, 185mm
1973โ€“1976, 240D, OM616.916, 3.69, 1.1 Liter, 185mm
1974โ€“1976, 240D 3.0/300D, OM617.910, 3.46, 1.1 Liter, 185mm

W116
1973โ€“1980, 280S, M110, 3.69, 1.1 Liter, 185mm
1973โ€“1980, 280SE, M110, 3.69, 1.1 Liter, 185mm
1974โ€“1980, 280SEL, M110, 3.69, 1.1 Liter, 185mm
1973โ€“1980, 350SE, M116, 3.46, 1.1 Liter, 185mm
1973โ€“1980, 350SEL, M116, 3.46, 1.1 Liter, 185mm
1973โ€“1980, 450SE, M117, 3.06 / 3.07, 1.3 Liter, 210mm
1973โ€“1980, 450SEL, M117, 2.65 / 3.06 / 3.07, 1.3 Liter, 210mm
1975โ€“1980, 450SEL 6.9, M100, 2.65 LSD, 1.3 Liter, 210mm
1978โ€“1980, 300SD, OM617.950, 3.07, 1.1 Liter, 185mm

W123
1977โ€“1978, 230, M115, 3.69, 1.1 Liter, 185mm
1977โ€“1983, 240D, OM616.912, 3.69, 1.1 Liter, 185mm
1977โ€“1981, 280E, M110, 3.58, 1.1 Liter, 185mm
1978โ€“1981, 280CE, M110, 3.58, 1.1 Liter, 185mm
1977โ€“1981, 300D, OM617.912, 3.46, 1.1 Liter, 185mm
1978โ€“1981, 300CD, OM617.912, 3.46, 1.1 Liter, 185mm
1979โ€“1980, 300TD, OM617.912, 3.46, 1.1 Liter, 185mm
1981-1984, 300TD, OM617.952, 3.07, 1.1 Liter, 185mm
1982-1984, 300D, OM617.952, 3.07, 1.1 Liter, 185mm
1982โ€“1984, 300CD, OM617.952, 3.07, 1.1 Liter, 185mm
1985, 300TD, OM617.952, 2.88, 1.1 Liter, 185mm
1985, 300D, OM617.952, 2.88, 1.1 Liter, 185mm
1985, 300CD, OM617.952, 2.88, 1.1 Liter, 185mm
Euro Spec
1981-1985, 300TD, OM617.912, 3.46, 1.1 Liter, 185mm
1982-1985, 300D, OM617.912, 3.46, 1.1 Liter, 185mm
1982โ€“1985, 300CD, OM617.912, 3.46, 1.1 Liter, 185mm
1978โ€“1985, 240TD, OM616.912, 3.69, 1.1 Liter, 185mm
1978โ€“1985, 280TE, M110, 3.58, 1.1 Liter, 185mm

W126
1st Generation
1981-1984, 300 SD, OM617.951 3.0L I5, 3.07, 1.1 Liter, 185mm
1985, 300 SD, OM617.951 3.0L I5, 2.88, 1.1 Liter, 185mm
1984-1985, 380 SE, M116.963 3.8L V8, 2.47, 1.3 Liter, 210mm
1981-1983, 380 SEL, M116.963 3.8L V8, 2.47, 1.3 Liter, 210mm
1982-1983, 380 SEC, M116.963 3.8L V8, 2.47, 1.3 Liter, 210mm
1984-1985, 500 SE, M117.963 5.0L V8, 2.47, 1.3 Liter, 210mm
1984-1985, 500 SEL, M117.963 5.0L V8, 2.47, 1.3 Liter, 210mm
1984-1985, 500 SEC, M117.963 5.0L V8, 2.47 /(Euro) 2.24 LSD/(Euro) 2.47 LSD, 1.3 Liter, 210mm

[ATATEXAN]

I stumbled on this thread looking for answers to dealing with my transmission in the Euro 350SE which is slowly but surely grinding itself to pieces. No immediate panic. From this thread it seems what I should do is have the tranny rebuilt (??? Or any point in a 4-speed autobox???) and find a 6.9 diff to bring down final drive ration from 3.46 to 2.65.

Comments?