Changing differential w115:

Changing differential w123:

LSD differentials:

Differential overhaul:


Different final drives

The differential is the same on a w1114, w115, w116, w123 and w126 (first generation) a first generation w126 diff will fit on a w114,but wont fit on a 1986 w126.

If you are switching to a final drive from a v8 to a car without v8, you have to switch the yoke, and with that the “spacer washer”.

Finaldrive gear ratios


1st Generation mounting
1972-1980, 350 SL/SLC, M116, 3.46, 1.1 Liter
1973-1980, 450 SL/SLC, M117, 2.65 / 3.06, 1.3 Liter
1981-1985, 380 SL, M116, 2.47, 1.3 Liter
1981-1982, 380SLC, M116, 2.47, 1.3 Liter
2nd Generation mounting
1986–1989, 560SL, M117, 2.47 / 2.47 ASR / 2.47 LSD, 1.3 Liter


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


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


1973–1980, 280S/280SE/280SEL, M110, 3.69, 1.1 Liter
1973–1980, 350SE/350SEL, M116, 3.46, 1.1 Liter
1973–1980, 450SE, M117, 3.06 / 3.07, 1.3 Liter
1973–1980, 450SEL, M117, 2.65 / 3.06 / 3.07, 1.3 Liter
1975–1980, 450SEL 6.9, M100, 2.65 LSD, 1.3 Liter
1978–1980, 300SD, OM617.950, 3.07, 1.1 Liter


1977–1978, 230, M115, 3.69 (3.58) 1.1 Liter
1977–1983, 240D, OM616.912, 3.69, 1.1 Liter
1977–1981, 280E/280CE M110, 3.58, 1.1 Liter
1977–1985, 300D, OM617.912, 3.46, 1.1 Liter
1979–1980, 300TD, OM617.912, 3.46, 1.1 Liter
1981-1985, 300TD, OM617.952, 3.07, 1.1 Liter
1982-1985, 300DT, OM617.952, 3.07, 1.1 Liter
1982–1985, 300CD, OM617.952, 3.07, 1.1 Liter
California Special, the om617a equiped cars got a 2.88 differential instead of the 3.07 (as far as i know, some claim they have had “federal cars” that had the 2.88 aswell.
1985, 300TD, OM617.952, 2.88, 1.1 Liter
1985, 300D, OM617.952, 2.88, 1.1 Liter
1985, 300CD, OM617.952, 2.88, 1.1 Liter

Euro Spec w123

1981-1985, 300TD, OM617.912, 3.46, 1.1 Liter
1982-1985, 300D, OM617.912, 3.46, 1.1 Liter
1982–1985, 300CD, OM617.912, 3.46, 1.1 Liter
1978–1985, 240TD, OM616.912, 3.69, 1.1 Liter
1978–1985, 280TE, M110, 3.58, 1.1 Liter


1st Generation w126

Years,Model, Engine, Differential Ratio, Differential Case Size

1981-1984, 300 SD, OM617.951 3.0L I5, 3.07,
1985, 300 SD, OM617.951 3.0L I5, 2.88, 1.1 Liter (California from 10.1984 in California: 2.88, 1.1 Lite
1984-1985, 380 SE+SEL, M116.963 3.8L V8, 3.27,  from 1981-10, 2.47, 1.3 Liter
1982-1983, 380 SEC, M116.963 3.8L V8, 2.47, 1.3 Liter
1984-1985, 500 SE+SEL, M117.963 5.0L V8, 2.82, from 1981-10, 2.24, 1.3 Liter
1984-1985, 500 SEC, M117.963 5.0L V8, 2.24/2.24 LSD (2.47?) 1.3 Liter

2nd Generation w126

Years, Model, Engine, Differential Ratio, Differential Case Size
1989-1991, 300 SE, M103.981 3.0L I6, 3.46 1 Liter
1988-1991, 300 SEL, M103.981 3.0L I6, 3.46, 1 Liter
1986-1987, 300 SDL, OM603.961 3.0L I6, 2.88, 1.1 Liter
1991, 350 SD, OM603.97 3.5L I6, 2.82, 1.3 Liter
1990-1991, 350 SDL, OM603.97 3.5L I6, 2.82, 1.3 Liter
1986-1991, 420 SEL, M116.965 4.2L V8, 2.47, 1.3 Liter
1986-1991, 560 SEL, M117.968 5.6L V8, 2.47 ASR/2.47, 1.3 Liter
1986-1991, 560 SEC, M117.968 5.6L V8, 2.47 ASR/2.47 LSD/2.47, 1.3 Liter

diff housing 300SE

w124 – probably only automatics so far…. and probaby has some of them wrong to..


200e unkown for now

250d om602 185mm?
3.64 fivespeed manual

260E 124.026 185mm
1987-89 3.27 No ASR
1990-91 3.07
1992      2.87

300E 124.030 185mm
1986-89 3.07 No ASR
1990-92 2.87

300TE 124.090 185mm
1988-90 3.27 (1988-89 no ASR)
1991-92 2.87

300CE 124.050 185mm
1988-89 3.07 No ASR

300CE 124.051 210mm
1990     3.27
1991-92 3.06

E320/280 – 124.028 / 124.032 / 124.0992 – 210mm
1993-95 2.65

320CE – 124.052 / 124.066 – 210mm
1993-95 2.65

E420 124.034 210mm
USA 2.24 with/without ASR
Euro 2.65 with/without ASR

E500 124.036 210mm
1992-95 2.82 ASR

E500 124.036 210mm
1992-95 2.82 ASR


300D 2.5T 124.128 185mm
1990-93 2.65

300D NA 124.133 / 124.193 185mm

300D turbo 124.133 / 124.193 185mm

E300D om606NA 124.131 185mm
2.82 according to internet, but i have only found 3.07 on om606 automatic cars, the fivespeed had something along 3.46, will update this




Chart of the different differentials on the w201 chassi


250TDT om605 turbo manual fivespeed 717.460



E300d Turbodiesel om606 turbo



55 thoughts on “differentials, gear-ratios and compatibility”

    1. what i found a w203 c240 gasser with a sixspeed manual should have a diff-ratio of 3.46..
      it should be easy for you to see under the car.

      1. Hello Linus,

        Would you happen to know which differentials would fit as replacements for my 1996 S124 fitted with OM606.910 diesel engine, 722.4 auto box?

        Ratio is 3.07 but I haven’t found any reliable method to determine the dimensions or alternatives units.

        Many thanks, David

        1. Hey David,
          “al” w124 diffs will fit the chassi as far as i know, but do you want a different ratio, a bigger differential or something else? you need the correct driveshaft vs the differential type..
          they have some different widths, and thus would require different driveshafts, The w124 open diff should be somewhere along 24cm and the ASD version has a width of about 28.5 if i recal correctly.

          Your s124 ought to have a 185mm diff, but i have stumbled upon different sizes on s124 om606 cars where they al “is supposed to be the stock diff”

          il look into it closer when i get back home.

          Do you have ASD?


  1. Hi,

    I’m looking to put a 3.07/3.06 or other ratio in my W126 Gen I 1985 500 SEC. Can I simply swap the rack and pinion from any other Diff listed above as long as the final drive is 210mm? I’m specifically looking at a Rear Diff from a 1973-1980, 450 SL/SLC. Would the diff bolt up directly? Thanks!

    1. It will fit straight away, a v8 differential is the same no matter what car (up to 1985) so a 450sl will do just fine, you might need to keep your driveshafts, I’m not shure about the width of the r107 vs w126.

          1. the thing you need to check is that you have the starter on the right side of the engine, if it has, then it will fit, how much work there is to get it to work i dont know, probably quite an upgrade from the stock w123 auto anyhow, got a w201 with the auto, and realy like it, was surpriced how good if felt compared to the many diesel autos ive driven (300tdt) althou that might be due to bad maintance on the diesels.

            i think the hardydiscs/flange is the same size, but do check the lenght of the gearbox, it might differ quite much.

  2. Hi,

    I think the naturally aspirated E300 Diesel w/OM606 have 3.07 final-drive ratio with automatic gearbox.
    Haven’t seen other ratios to this model.

    300D Turbo, 300TD Turbo and E300 Turbodiesel with automatic transmission does all have the 2.65 ratio.

    1. 300d w123 or w124?
      and a 300SE w126 or w140?

      if the 300d is a w123 and the 300se is a w126 you wont gain anything by moving the diff, they have the same ratio and size, + the diff from a w126 300SE from 1986 or newer wont fit a w123. and the w126 gen2 diff (1986 or later) wont fit on a w124 either.

      i dont know the gear ratio of the w140 300SE, but dont think it will be better than one of a w124 300d

  3. Have a w111 with 4.08 ratio and want to swop for 3.23 – 3.27 which Mercedes vehicles can I get this ring gear and pinion from or from which after part reseller
    Thanking you in advance
    Kind regards,

    1. i dont know realy, i think the larger v8s had like 3.46,
      the 300SE 6.3 differential is 2.82 i think, and that is the lowest, but those are extremely rare on the other hand, if you find a ratio at 3.27 or 3.23 or something alike, please post and il update with those ratios aswell

  4. From what I have read

    The w108 w109 w110 w111 w112 and w113 ring gear and pinions were interchangeable

    I am trying to find a economical source for a ring gear and pinion for my W111 of a ratio of 3.27 so at about 3000 rpm it travels at 120 kmh

    South Africa where I live is flat and I don’t want to rev the motor

    Mercedes OEM Number 1093500139 superseded to 1093500339

    Kind regards,


    1. I dont think aany of them will, the w111 is a whole different diff than w123/w126/w116. I would look at a larger v8 w108, that’s your best bet i think

  5. The W111 diff’s are generally 4.08 on US cars, and 3.85 or 3.69 on Euros. The best diff to use is from the W108 280SE 4.5 which is a 3.27, however the housing is physically larger, due to the size of the crownwheel so you need to change the whole unit. These also have a cooling tube and therefore will not fit into a W113 unless you cut part of the floor support or modify the cooling tube.

    1. thats great info Ben! what about the 300SE 6.3 isnt that 2.82 or 2.88 in diffratio? althou those are extremely hard to find

  6. I have a 1969 w115 currently having a 200d. The body originally had a 220 gas in it and was transplanted by the current engine. the diff remains but the engine and tranny was changed. My concern is why is it running only at 60 – 80 km/hr and maybe until 85-90 km/hr at the most but im not trying since the engine is screaming at 70 -80 km/hr. How can i make it run to do 130 km/hr as they are saying to be the top speed of 200d? thanks

    1. a 220gasser you probably have a 4.08,

      anyhow, the 3.92 is what the om615 had stock, what i presume is your engine om615 = 200d and 220d. so its not super far of from stock, but stock is fucking horrible, so i would swap it as soon as possible :P like 70km/h is the absolute top one wants to drive the car :P

      the engine is screaming, its a pain in the ass, i dont know if you have an automatic and is missing the fourth gear? but if not, swap for a 3.69 or 3.46, they are somwhat easily optainable, and if your engine is healthy, it will still be peppy and nice to drive (about the same)

  7. Hello Linus,
    i am building a slc rally car and need lots of power from standstill.
    is it the higher the ratio the faster acceleration?
    i am thinking of 3.46 or even higher?
    3.69 or even 3.92
    80s w123 diff will fit an 80s slc right?
    dont care about top speed or mpg

    regards jeff

    1. yes it will fit,

      as long as the SLC was a straight cylinder car (280SLC) you wont have to swap the flange/yoke of the differential either. 1985 is the magic year that the differentials cant pass.

      regarding ratios, you are correct, the ratio is the amount of revs the driveshaft turns the ingoing axle to the diff, for the wheels to turn one revolution.
      3.69 revolutions of the propshaft/driveshaft/cardanshaft whatever you choose to call it, will turn the wheels one rev.
      a 2.24 will thus be a lot faster at the same enginespeed and same gear in the gearbox.

      a 3.92 or 4.08 from a w115/w114 will fit to, but make shure you have rpm enought to not rev out the engine before you want to.

  8. I’ve got a Mercedes 500 sec 1991 I’m after a 3.69 or slightly lower ratio all I need to know is which Mercedes model it would come out of I just need the gears and pinion

    1. 3.69 or lower, higher RPM or lower?

      the closest straight fit is a 3.46 from a 300SE, althou you need to swap the yoke/flange for the flexdisc since the v8 has a bigger one.
      if you more RPM, the only option i can think of would be fitting a 4.08 or 3.92 diff from a w115 220d/200gasser, in the housing of a 300SE (that has the smal housing, compared to the big housing you have today)

      thats the closest possible solution i can think of now, it will probably not be a straight fit, but might be doable.
      might be some measuring and fixes to get the bearings+cogs properly aligned.

  9. i have a 400e 1992 v8 (nitrous) and I want to do 1/4 miles with , which is the most higher ratio I can put on without big modification

  10. Finally after 2 years I fitted the 2.49 differential on my 1981 Mercedes 280E. It was a Jo doing it in the garage. I had to modify the hole on the subframe they were too far out. I measured and measured after the 12 time it fit. I had brought the CV axles new locally to get the lifetime warranty these had to be modified on the rotating parts that go in to the differential since they weren’t the can type axles. I took a little material off the end where the bolts fit and they rotated freely after that. I am waiting now on a front flex joint, transmission mount and center sleeve for the driveshaft after that I’ll be back to tell you more.

  11. I have a 1984 300SD that the RPM ‘screams’ at 70mph. If i switch to a 1985 2.88 diff. will it make much of a difference? What swap will give me the lowest RPMs? thanks

    1. it wont make much to go from a 3.07 differential to a 2.88 (2.88/3.07 = 0.93)
      So you will loose about 7% on the rpm.

      Simple put, anything lower will be lower, 2.65, 2.47 or whatever you might find.
      a swap from 3.07 to 2.88 might not be worth it in my world, a 2.47 is a bit easier to find than the 2.65, and althou you need to swap the yoke, its a straight fit besides that (380SE from 81 to 85 should have it)


      1. Linus, thank you for your insights. It seems then, the 84-85 500SEL with the 2.24 gear ratio would be the lowest. So can I assume a decrease from a 3.07 to a 2.24 would yield about a ~30% drop in RMP’s?

        1. yeah, that ought to be about it.
          What cruising speed is your goal?
          id say about 2000-2500rpm at cruising speed is about optimal,

          i have a w126 SEC with a om605 turbo and a 2.47, and since its a fivespeed i net out at about 1600rpm at 60mph, its a tad to low for those speeds, but 130-140km/h + its darn sweet.
          You dont gain much mileage by decreasing rpm to low.

          my old 300TDT w124 had a fourspeed automatic, and its 2.65 was pretty deacent, so id say paired to a fourspeed, 2.47 would be nice, 2.24 might very well turn out to low, but if you go down that route, please get a video aswell as some feedback :) its down to what speed you plan to drive at :)

  12. I would like to drive at 70mph with very low RPMs to get good MPG, when I drive slow at 40 mph the RMPs is about 1500 and i get about 37mpg, when i’m driving at 70mph the RPMs are about 3000 and I get about 25mpg

    1. Yeah, but that increase in mpg isnt purely down to the RPM only, you have an exponential increase in airresistance with increased speed, you will drop a bit, but 1500rpm at 70mph wont match the consumption you get at 40mph at 1500rpm.

      for 70mph,a i would suggest a 2.47 or something alike, it will be slower, it will rev less, and get a tad higher mpg (not a promise, every engine has an “optimal” rpm they runs best at.)

  13. hi,i’d like to change the m110 cab engine on my s280,which diesel or v8 engine will fit with few or no modifications pliz.

  14. I have a resto-mod situation and need some firm advice. W108 (250SE) is being fitted with M119.066 engine/722.353 automatic 4 speed transmission. My original diff is 3.6 ratio and will probably be melted from all that extra torque. I am thinking about changing the complete rear end sub frame with either w114, w123, w126 (or whatever I can actually get my hands on) since it might be the easiest fit, but really not sure what diff ratio should I aim for. Wheels will be either 14′ or 15′ with a lot of rubber for soft driving. The plan is to make smooth low rev cruising car for comfortable speeds at about 60-80MPH or say 2500-3000rpm… Please help me, point me to the right direction. What diff or sub frame type should I aim for. 2.5 something i guess…Thanks for your reply in advance. Thomas

    1. 2.5 or something alike might very well be a very good option.
      the stock diff will probably sustain, but no, the gearing isnt the best.

      im not convinced that a w126/w123 subframe would be a easier swap than for example a bmw subframe. those might very well be easier to obtain, cheaper, and be better to build on.
      Finding good driveshafts and differentials from a w126 and w123 + finding good diff ratios to the old w123/w126 isnt that easy anylonger.
      Where BMW is a lot more common atleast in this part of the world.

      the w124 and w201 differntials isnt that durable, and often “sings” in my opinion.

  15. Are all ’85 300Ds equipped with the 2.88 ratio diff? I want to put that ratio into my ’84 300TD and I’ve found a guy parting out an ’85 300D. Is there a way to determine, before removal, if it’s the desired ratio?

    1. No as far as i know only the 1985 om617A cars in California got these, so no, seems to be a California specifik differential

    1. Any w124 or w201 transmission would work (from a straight engine)
      Althou you probably need to alter the driveshaft, and get a clutch+flywheel to match it.

      Any box would survive “normal” driving without a problem imo, but how do you plan to use it?

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