Changing differential w115:  http://mbturbo.com/how-to-change-final-drive-w115/

Changing differential w123: http://mbturbo.com/how-to-change-final-drive-w123/

LSD differentials:  http://mbturbo.com/lsd-differentials

Differential overhaul:  http://mbturbo.com/overhauling-a-differential/

Compability

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”. or the other way around, from straight-engine to a v8 car.
This is because the yoke/flange are of a different size. You could also swap out the cardanshaft/driveshaft to one with the right size yoke, if you for example are building a tuned w115 and need something beefier than the stock flexdisc

Finaldrive gear ratios

R107

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

w114

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

w115

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

w116

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

w123

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 below where the om617a equiped cars got a 2.88 differential 1985 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

w126

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..

Gassers

200e unkown for now

250d om602 124.xxx 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
1992-95
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

Diesel

300D 2.5T 124.128 185mm
1990-93 2.65

300D NA 124.133 / 124.193 185mm
3.46

300D turbo 124.133 / 124.193 185mm
2.65

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

 

 

w201

Chart of the different differentials on the w201 chassi

w202

250TDT om605 turbo manual fivespeed 717.460
3.64

 

w210

E300d Turbodiesel om606 turbo

2.65

 

91 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?

          /L

  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,
    Victor

    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,

    Victor

    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)

      /L

      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

  16. I have a 2.3-16 automatic and I want to put a manual transmission other than the 717.404

    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?

  17. I have a W114 from 1969 and want to swap the differential for an early diff. from a W126 500se. So yesterdag i bought a 2.82 with number 235814 of 335814.(first nummer is a 2 or 3) The guy that sold it to me told me that it was a diff from a 1980 500se (euro version) , but i am not 100% sure. I searchd for this number on the internet , but could not find any info. Linus, can i assume that this is a 500se diff? Those numers, i can’t find any info about them. Thanks for the reply

    1. Yes, the 2.82 differential i have was from a 500SE, those numbers are probably just serial numbers or something unimportant, dont put to much time on those since they dont acctualy matter that much.
      Since its a w126 diff from a v8 the yoke/flange will be bigger than what you have today and wont fit.

      are you going to swap the engine and driveline altogether or looking for a better ratio more suitable for todays trafic?

  18. Hi, great article! I’ve got a ’76 240D with a 4 speed manual. I found an ’80 300CD with what seems to be a strong engine, fairly clean. I’m planning an engine swap, my little 240 needs some more pep! I didn’t see listed a 1980 300CD on your list for what the final drive ratio would be..i’m assuming a 3.07? I figure I’ll swap both engine and rear diff, and keep my 4 speed manual. Doable? Thoughts? Thanks!

    1. Well, I didn’t realize the 300CD doesn’t have a turbo, so nevermind. I am looking for a 300TD to swap into my W115. Price has to be right!

      1. the 300CD ought to have a turbo, its a US/america specific car and nothing that came stock in europe atleast.
        But any stock 300CD c123 (w123) ought to be a turbo.

    2. yes. 3.07 ought to be the gear ratio of that car if its a stock om617 turbo and not something built later by modding a gasser c123 :)
      ive lsiter 1982-1985, but might be wrong about that.

  19. Sorry this is really late. I have a 1991 300e-24, 124.031 chassis (m104.980 engine with 722.359 gearbox) and I need a new differential. There seem to be plenty that will fit a regular 300E available on ebay but I am hesitant to buy because I am afraid of getting the differential ratio wrong. Any chance you know what diff ratio I need for this slightly rare, 24-valve engine?

    1. if you go under the car, and check on the right side of the diff, you should have the gear ratio of the diff stamped on the casing.
      there is a little ear that sticks “out” at the bottom at the side of the backplate.
      get a flat-screwdriver or something to scrape old rust and dirt of that ear, and then a sandpaper or alike to get it a tad shiny, that way the numbers pops the best.
      OPOSITE side of these in this link
      https://mbturbo.com/wp-content/uploads/2016/03/3.07-differential-w123-used-2.jpg
      the w123 and early w126 diff was stamped on the left side, yours is on the right side.

      the ratio is one thing, you also need to make shure you get the correctly sized flange, and the correct width of the diff.
      if you have a ASR or a ASD diff it will be wider, and some newer diffs have the 100mm yoke instead of the older 90mm or 110mm yoke (center-hole to center hole on the diff fastening screws)

      your diff-ratio would probably be something like 3.27 or 3.07 id guess.

  20. Hi Linus. Thanks for a very interesting page. I am considering swapping the rear diff on my 1968 W114 230.6. Will any of the diffs from the R107 fit ?

    1. yes, any of the diffs from a r107 up to 1985 should fit.
      BUT if you grab one from a v8 r107, you would either need to swap the flange/yoke of the diff, or change/rebuild your driveshaft to accomodate the larger flexdisc.
      your w114 today have a 90mm CC flexdisc, the v8 diffs is at 110mm CC

      1. Ok, thanks for the clarification. I am interested in effecting the greatest change possible to the driving experience with the least amount of modification. If the flange/yoke swap that you describe is complicated, then I might need to consider an alternative. Maybe something from a OM617 model ? Mine is a Eur spec example, if that makes any difference.

  21. Hello,
    I have a 1974 R107 450sl. The car had a engine swap before I acquired it, they converted it to a M130 straight 6 (dual zenith) from a 72 280s. I am swapping back in the R107 4.5L v8. I removed the 6 and see that they used the transmission from the 280s as well. 722.1. So I guess I am going to switch the transmissions back once i find the 722.04. My question: How can I check if the differential was changed from the 450sl to the 280s? If they did change the diff, should I be changing it back to the 450sl original? What are the differences?
    When I did drive the car before removing the M130 engine is was very slow. it felt like it was taking off in 4th gear, although I never got it up above maybe 40 mph.
    thanks in advance.

    1. since it felt like it was slow, and started in a to-high gear, they most likely didnt swap the rear differential.
      The gearing of the diff is stamped at the housing of the diff.
      At the rear of the diff, bottom left corner, there is a “ear” that sticks out besides the backplate, under the rust, crud and dirt there is a number stamped there.
      your should read something like 3.07 or 3.06.
      if so, the diff was not swapped. h

      the thing is that the flexdiscs are differently sized at the diff atleast between the v8 and straight.six engines.
      what might be a problem is that the front flexdisc or driveshaft was altered to fit the m130 engine and gearbox,
      In that case you might have to restore that to fit a v8 engine and gearbox in there again.

  22. Hello, I am doing a OM605 Turbo Manual swap from a S202 C250TDT to 190D 2.5, do I need to change the diff from the S202? Or just keep the original diff from a 190D 2.5 auto ? Thanks

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  24. I have a w116 450 se automatic 1980. What rear differential can I put on my car from 116 or 124 with a gear ratio of 3.06, 3.07 or 2.82 LSD. If you take the gears from the 126 or 124 differential, they will go for installation in my diff? .Thanks for the answer .

    1. you should already have a 3.07/3.06 differential as far as i know.
      why do you want to change?

      the 126 didnt have a 3.07 diff, and the 124 differential is from my knowledge, not easily adapted to fit in the 116 housing.
      you could theoretically swap the innards from a 2.82 gen2 w126 diff, but it wouldnt be worth the hassle in my opinion

  25. Hi Linus,
    Thanks for a informative page with a friendly atmosphere.
    I’m having a W211 E500 4-matic from 2004 with 722.672 gearbox and 3.07 diff (same ratio in front and rear differential). I would like to change my rear differential to a bigger one and stronger drive shafts.
    Do you know if there is any available differential with correct gear ratio that would be a suitable choice?
    If not, do you know if there is any suitable diff that could be a donor for the internals to achieve correct gear ratio if I for example install the bigger differential from E55 AMG with gear ratio 2.65.

    Looking forward to hearing your reply/input.

    1. Hi there Johan!
      (updated for the others)

      We kept on discussing this issue on an alternative media but thought id update others.

      Johan bought a 3.06 diff from a r230 Sl63 AMG that looks like it is a 210mm diff.
      an open diff, but mountingpoints looked to be the same as the w211, althou the axleshafts had larger splines, and the front yoke had four fastening points.
      Hopefully it will work, the ratio difference is quite close, and hopefully wont affect driveability nor the ASR/ABS system.

      Still untested, not shure if this will fit, but this was the next step for his AWD m104 turbo w211

  26. Hi Linus.
    Great page this!!
    Could you help me out, since I don’t know if a 2.87 GEAR SET from a W123 will fit in my W114 casing??

    1. i dont think the w123 ever came with a 2.87, it do have a 2.88 and that gear-set “should” work in your casing since they are the same size, there are different types of bearings thou, and im not shure it would be a price-efficient modification/work.

      What sort of engine do you have in the w114, and what gearbox?

      if its a w126 2.87 gear-set it wont fit in your w114 housing, its of a completely different size.

  27. I own a 2004 Mercedes cl55. I’m looking to purchase ring n pinion something between 308 to 355 ratio.
    Any help please? We are building this car to be the quickest w215 in the world. Everything has been built now we are doing the rear differential.
    Thank you
    Rick@FullThrottle..

    1. the numbers themselves, refers to the diameter of the ring/gearing in the differential.
      how big the differential is, size-wise to accomodate the gearing.

  28. Great site with invaluable information
    Just discovered that my sloppy 1973 107 rear diffi
    is a 123 – 3.7 gear ratio differential. Is a 3.6 gear ratio diff out of the same year 107 a straight swap out?
    I’m concerned about the axels and drive shaft flanges matching up.

    Thanks,
    Frank

    1. depends on model and equipment,
      i have one w123 with ABS, but neither of my w126s have it.
      i also have w201s and w124s without ABS, and those with.

  29. Hi ,everybody. I’m new Mercedes, so I’ll need help. I have a 1990 300SE, second gen 126, and swap engine and installed a 603 turbo from a 300sdl 1987. Besides that, I just installed a 722.5 five speed tranny. But the diff is 3.46 and I wish to lower it to 3.07 or so. From what M Benz can I get it?

    1. For that car i think you are quite limited, its basicly gen2 w126 and gen2 r107 that would be compatible as far as i know.

    1. Nothing i can guarantee unfortunately, but i would guess that most cars from the same era and size would be somewhat compatible, often there are some minor changes, but nothing big.
      What sort of diff are you looking for?

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