Ford Transit Diff Ratio’s & Axle Swaps

“My van is screaming its nuts off on the motorway”, is a common complaint & leads many owners of rear wheel drive Transits get in touch hoping a remap will fix it but it is a common misconception that a remap can change this.. Whilst more torque & a quieter tuned engine can sometimes give the impression of less rpm for any given speed travelled, its just an illusion.

The true  solution is a different axle ratio, achieved by an axle or diff change.. on MK7 Euro 4 ( 2006-6 to 11-2011 if you have a 5.11 or a 5.13 ratio diff fitted currently, an indicated 70mph will be made using over 3000rpm..  Anything over 3000rpm can be noisy & uneconomical . I’d recommend around  1  “point” reduction  so something in the low 4’s like a 4.27 would suffice without acceleration suffering too much. How about the 3.73 ?  An excellent choice as 70 will come up about 2600-2700 rpm but a remap is needed to pull it if you’ve 100ps. 115’s & 140’s would pull that  much better , so get in touch to discuss vantuner’ in house developed custom tuning options.

On Euro 5 MK7’s the axle ratios are taller to start with as the Euro 5 has 20% or more torque at lower RPM to start with & the axle choices can be as tall as 3.31. These axles can be fitted to Euro 4 MK7 no problem, so if youve 170ps plus, consider one of these.

How do you tell what you have already  ?  register & login to Ford ETIS & you can see what it came from the factory with. Or there is a tag on the diff cover with 3 digits that you can work out the ratio from. Or spin the wheels off of the ground & count how may wheel turns compared to one propshaft revolution.

A common query is if i fit a minibus axle what will the RPM be at 60 or 70 mph on my tipper . It depends on what diff ratio you have & what ratio the minibus axle is as the ratios can vary. Any seller worth his salt should be able to tell you the actual ratio of what he is selling.

MK6 Transits – only the 135ps came with anything lower than a 4.63 so maybe an axle or diff from one of them might be suitable. People do fit MK7 axles but its not a simple plug & play, as you need MK7 handbrake cables & MK7 ABS reductor rings ( if your MK6 has ABS )

Finally whatever you do , your speedo will read wrong untill new axle ratio is programmed in to the ECU/BCM.

Vantuner doesn’t actually do axle  / diff changes or give advice on what your new RPM will be etc but recommended  Transaxle Services in Halifax  who fitted used diff’s at a reasonable cost but were considering retirement in 2018 so i’m not sure what option’s you have now

66 thoughts on “Ford Transit Diff Ratio’s & Axle Swaps

  1. Hi , if doing an engine and ecu swap , would you be able to program the new ecu to the old bcm? I’ve tried with forscan and can’t seem to manage it

  2. Hi mate I have a 2009 transit mk7 rwd minibus 17 seater twin wheel 5 speed and as the same as everyone else on your thread I’m not happy with the high revs at top speed 62mph (limited) do you know where I can get a diff and what one I need to get the revs down lower thanks chris

  3. Hi,
    I have just bought a 2008 Mk7 Transit Minibus to convert into a camper but I’m not too happy with the 3000rpm @ 65mph situation.
    Looking at your previous comments, it would seem as though a diff change is the way forward.
    My main concern is the constant 3000rpm that the van would endure for pretty much most of the day if traveling long distance. Is the engine up to that? Other than being less economical and noisy, could this potentially damage the engine or is it designed to be driven at that level for prolonged periods?
    Thanks in advance.

  4. 2008 mk7 jumbo 100hp screams at 60 mph (high rpm)
    5 speed box
    What can I do to lower rpm.
    Does it matter if I put a rear axle in from a van with a six speed box or do I need to replace with one from a van with a 5 speed box

    • The diff’s are the same in 5 & 6 speed vans as in the fitment is the same so just find the right ratio & you’ll be fine.

  5. Does anyone know the make of the rear axle on a mk7 awd. 135ps

    From the vin plate I got T-51 ratio 3.73 but is this a Dana axle or a Ford and if so what model/type just interested to know possibly thinking about a diff lock.

  6. Hi Martyn,
    I need some advice from an expert. I have a 2005 300 MWB Campervan conversion, which will pull away in 2nd most times, but is screaming at cruising speed in 5th. It’s been re-mapped so bags of power. Sounds like a diff swap would be the simplest way to go, but which diff would you suggest? Thanks. Ed Mason

    • Hi Ed, assuming yours is a real wheel drive, you probably have a 5.11:1 or higher reduction ratio ( they ago up to about 5.88:1) a 4.27:1 will improve things & is a nice compromise. a 3.73:1 would be nice on motorways but would be slower on acceleration. Contact Transaxles Halifax for a quote on drive in – drive out replacement

  7. Hi I have a 2008 rwd mwb ex highway van I’m at 3200 at 70mph is this OK and can I get the rpm down without a diff change? Thank you

  8. Have you anyone in Kent near dartford that can activate cruise control and how much mate. Ex rac awd. Mk7 2.4 140bhp 2010. Many thanks

  9. I need to upgrade my mk1 transit rear axel. I was hoping to put a transit custom rear axel on it buts now sure of the Ratio’s as I have a type 9 gearbox on it and a 2l Zetec engine in it. Any help would be appreciated

    • Hi, I have a mk6 2.4 125, rwd 5 speed 2003 transit recovery truck, was a tipper. Iam wondering on the gains of putting a mk6 2.4 5 speed mini bus rear axle In too mine. Could you tell me the difference in rpm at motorway speeds ie 60mph.

      • I cant sorry, as there is not just one “MK6 Transit minibus axle” of a certain ratio. To work it out, take your current diff ratio, the new diff ratio you plan to fit, & work out the percentage difference betwen the 2 & use that figuare to reduce your RPM at any given speed -Example current diff is 5.13 , new ratio 4.53 , with some nifty calculator work, you’ll see difference is about 11%, so if at 60mph your RPM is 3000, it would reduce by 11% at 60mph with the new diff. ( example numbers are approximate) .

  10. Hi Martyn

    I have an ex-RAC Transit with 130bhp. It also has cruise control supplied by you. I am in the process of fitting a higher rear diff, 3.9 or 4.2. I hope I have sufficient power for that.
    My actual question is can you recalibrate the ECU so that the speedometer and odometer are correct? I’m booked in with my local Ford dealer, but, well they are a Ford dealer and I have no idea what I will get back.

  11. Hi there mate iv been reading all these post I would really like your knowledge please has iv just built my own recovery truck I’m pretty good with welding since school days and only it’s took it back up on a few projects my work has turned out real nice just converted a mk6 tipper in to a recovery 54 plate and when i took it on a trip to 284 mile there and back it would it would only do 65 70-72 down hill pushing it 3200rpm in 5th gear it’s a 5 speed what can I do to get more top end speed out of it aswell has have enough power for streets and driving round local but want a little bit more top end so I’m not getting stuck in slow lane on motorway what’s the choices pal would a remap help is my vehicle restricted or is it because it was a tipper I would be grateful for any help

  12. Hi Martyn, I’ve got 10 plate mk7 100 T350l 2.4 with 5 speed gearbox and 5.11 twin wheel axel (ex Luton), which is now a recovery truck, at 62-65mph it sits at 3000rpm which is annoying on motorway, which ratio would you suggest to make it sit on lower revs on motorway?
    Thank you.

        • I mean if your 100ps makes good power already or is tuned, ” makes good power ” refers to the fact that some make a lot more than others . Some are fast some are slow, dyno 5 x 100ps transits & the power curve & peak numbers will vary significantly.

          • Another question: is the diff from single wheel axle will go on twin? And if yes, which one of these two you would suggest in my situation: 3.91 3.58? Considering that I would like to come for remap after diff installation.

          • Best ratio depends on what model, & power you have & what weight you carry etc. Best to call Transaxles in Halifax , they are the experts.they can answer the fitment question as well.

  13. Hi I’ve got a mk6 115psi 5 speed twin wheel transit. The usual going past 60 mph and creeping past 3000 revs. What’s the best fix. How can you tell which axel has which ratio and what’s the best to get? Mk6 or 7 axel or do i look for 6 speed gearbox? It’s a recovery truck but was a tipper and pulls up banks fully loaded no problem but lucky if I get 350 miles to a tank driving at 60. 07773029111 cheers paul

    • There is a tag on most diff’s Paul, that has the ratio on it, on yours it sounds like you have a ratio of 5+ & you could try a 4+ say 4.26:1 or thereabouts. Transaxles in Halifax, U.K ,offer a supply & fit service. Fitting a 6 speed box isn’t practical as the speedo drive signal is very different

  14. Hi, i have a 2008 mk7 jumbo Transit 140 twin wheel, which at 70mph is around 3000rpm. So I guess fitting a 3:73 diff would be better. Can the diff be changed and set up with the axle in place or does it need to come off to be set up?

    • Diff can be changed in situ. Transaxles in Halifax, U.K , do it in the time it takes to get a maccy d’s across the road. Its £450 (2016) & they fit used ones of unknown mileage that work well but may or may not last as in stay quiet over time. I’ve used them myself, a good cheap service but consider for a new unit, with the hassle of shimming in correctly if choosing that route.

  15. I have a mk3 sub with a mt75 gearbox. Is it possible to have a higher top speed rear axle? I know it is old but I love my motorhome. If it is possible what sort of price am i looking at?

    • You can Alan, its very expensive unless used parts are utilised. Transaxles Halifax (at around £470), have many happy customers & supply & fit very quickly , & are the cheapest overall but with used axle parts, its hard to say how many miles they will last. Using new parts may cost £1500 quid upwards.

  16. Hi my track mk6 transit 2.4 90hp long rve 60mh 4200rm to much so I bough mk7 back axle I look 4.27 so will be less rve and pull ok I hope thanks

    • An excellent choice Bernard, and very eloquently put , i must add. Give me a call if you would like more power once the axle is fitted.

  17. ’06 2.4 115 Luton doing 3,000 revs at 60mph, ideally I’d like to be doing 2,000-2,500 revs at 60mph or 3,000 at 70mph, I’m near Brighton after some quotes to get more mpg.

    • The TDDI isn’t the best engine for economy tuning, although some gains can be made when tuned in conjunction with a couple of other mods / jobs. To change the RPM at any given speed, you will need an axle of diff change. Call me & i can go through it in more detail – 07956 555 666 – Martyn.

  18. I have a transit minibus with a 3.58 rear axle.2013
    Have bought and fitted a used axle 4.27.
    This has made the speedo read 72 mph not 62mph
    also change up light illuminating when it 6th
    Can the pcm be reprogrammed

  19. Hi guys,
    Advice on what to do with my mk6 jumbo tranist camper currently fitted a mk6 dana axle 3.7 ratio or so i belive but without the 6 speed box to match it struggles uphills and motorway inclines. Would van tuner produce enough power to overcome this on the curent 115ps engine. Would i bet better biting bullet and looking for a 4.2 diff instead and then tune 🙂


    • Irrespective of what engine you have presently, 4.2 something would be about the right one. I’d fit one then get it tuned.

  20. Hi Martyn , how much are the diff ratio change’s , ive got a mk7 transit 2.4 rwd 100ps ex rac van with im sure the 5.11 diff ..
    Also need cruise activating .
    are you still operating out of London or just up north

    • Hi, i dont do the the actual diff changes , i used a company in Halifax called Transaxles for mine. They fit used ones, it was £470. Mine’s not totally silent but is not far off , after nearly 13000 miles or so. I am London based ( actually Middlesex near Uxbridge) & have an agent in Glasgow. If you need cruise activating or any other ECU work like tuning or EGR delete etc please get in touch via the contact page or call me on 07956 555 666.

  21. G’day from Aus.
    I have a 2006 with 2.4 tddi 125ps.
    it has the stupid ASM gearbox.
    I have a couple of questions for you and am happy to pay for the advice, or just buy some stuff 🙂
    1. I need to convert this thing to either full manual or full auto, the ASM is crap and keeps stalling at intersections, including a nice wheel spin. Can you supply gearboxes and a manual tuned ECU? (I can arrange shipping to Aus)
    2. My van is doing 3400 revs at 110 km/hr.. I regularly drive this thing for 1600kms straight highway.. it needs to be changed, suggestions?
    3. All of the above aside, could you supply an ECU tuned for me for a manual, of which I can source my own gearbox and i have a Gscan tool so I can code the fuel pump/keys here.

    • Hi, I can supply an 125ps manual ECU yes, you would need to re-sync the immobiliser to get it running thats all. As for axle ratios, 3.73 to 1 would give around 110kmh @2600rpm.. 125ps will just about be OK to pull it but if heavy ,loads are carried all the time, consider something around 4.27 to 1.. for more info please email me directly – – Martyn.

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