Here are some frequently asked questions regarding the 4HP22 automatic gearbox.


My Autobox is now only able to select reverse. Why?

Your A clutch (forward drive) has failed and you will require a replacment autobox.

I have just fitted a rebuilt ZF gearbox but the gear shifting speeds is nothing like it used to be. I have to rev the engine really hard to make it change up. Why?

Check the setting of the kick down cable, if it is too tight the gearbox will think you have more throttle applied than is the case. Check and adjust the gearbox accordingly. As a guide the looser the cable, the earlier it will shift, visa versa the tighter the cable, the later it will shift.

What oil should I use in my Auto ZFHP22?

We recommend you use AFT Dextron 2/3.

What is the oil capacity of the ZF 4HP22 ?

Oil change approx 5 Litres

Dry fill approx 9 Litres

I have just fitted a reconditioned ZF autobox. I have filled the box with the correct amount of oil but have no drive at all, forward or reverse. Why?

The first thing to do is to remove the oil cooler pipe from the bottom of the gearbox (put a container under the open end to catch the oil) and start the engine. You should get a good flow of oil. If not the pump has been broken during installation and will need replacing/rebuilding. The torque convertor must be fitted to the gearbox, located correctly on the pump and locked into position before the gearbox is offered to the engine, otherwise damage will occur to the pump, resulting in no oil flow and subsequent to other parts of the autobox.

When I start my Automatic Range Rover in the mornings it takes a while to engage drive, it has not always done this. This has become worse in the cold weather. Why?

It sounds like you need to change the filter! In the cold weather, i.e when the oil is cold and more viscous, if the filter is partially blocked it will take some time for the pump to draw oil through it. Once the oil becomes warm it flows more freely and can pass through the filter more easily. Hence the problem only occurs when the oil is cold. To remedy this problem your filter needs to be changed. This should be done sooner rather later to reduce the possibility of damage to the autobox, by the clutches ‘slipping’ during this slow engagement.

I have a 4sp ZF, when I select “D” the vehicle won’t move, when I select “1″ the vehicle moves off. I can then select “D” and continue to drive normally. If I stop I have to start in first again. Why?

A sprag clutch has “inverted” and will need replacing. No further damage will occur if you continue to drive but you will need to select “1″ every time to start moving. A rebuild is required to correct this.

I have a 4 speed ZF Auto and it sticks in first gear in the morning or when cold and is reluctant to change up from 1st gear. Once the gearbox has warmed up it shifts normally. Why?

The governor valve is sticking, which can be caused by contamination. i.e. clutch plates or other parts disintegrating. The fine debris finds its way past the filter and tends to accumulate in the governor, causing it to stick. A temporary solution is to remove and clean the governor. The problem will often recur as debris from damaged parts continues to build up in the governor. If the problem continues after cleaning the governor then it may be necessary it replace your Autobox.

We have noticed many customers reporting this fault starting a few days after an oil and filter change and after researching this using our experience and the expertise of others in the trade we have come to the conclusion that as ATF oil is a detergent type oil, when the oil is changed this will dislodge and stir up settled debris in the autobox which in turn jams the governor valve. In light of this although it sounds controversial it is debateable if changing the oil and filter is a good idea, some say if the box it going to fail it will fail if the oil is good or bad and their advice is leave it alone. I am still undecided but the truth is I get a lot of calls from customers thinking they are looking after the autobox by servicing it and a few days later this fault occurs.

I have a range rover classic with V8 and ZF autobox and I want to remove the V8 and Fit a 300 TDi,

There are 3 ways to do this,

1) fit the whole stock 300 disco auto setup complete, this is the easiest option.

2) get the 300 auto backplate, flexplate, starter ring gear, converter and bellhousing and fit these to the V8 ZF, be careful not to break the pump.

3) contact www.mdengineering.co.uk and buy a adapter fit to fit the V8 ZF to the 300, this allows you to use the bigger V8 converter which is desirable over the smaller 300 one.

The above frequently asked questions are courtesy of Ashcroft Transmissions.

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Comments 66


  1. Marc says:

    Hello, is it possible to change a 4hp22(discovery2) with the 4hp24 (range rover p38)gearbox? and what is the difference?
    what do i have to change? or difficultes to expect?
    kind regards

    • Paddock says:

      Hi Marc. Sorry but the two boxes are not interchangeable as the torque converters and bell housings are different.

  2. samantha says:

    hi ive got a p38 dse and it has a issue selecting 4th as it will go in to 4th and then back into 3rd then stright away go back into 4th it has no fault codes in engine or gearbox if it needs a new box could you quote me for a recon box please

  3. Dave says:


    I have seen this once before and the problem was the autobox ECU, try and borrow one to try it,

    also check the engine air flow meter,


  4. alanza martin says:

    i have a rover p5b automatic BW35 i was inrom that the ZF-4HP22 is a straigh slot from the range rover classic is it possible to change ?

  5. dave says:

    No, you will need to use the 2 wheel drive ZF 4HP22 from a BMW or a Jaguar with the Range rover bellhousing and converter,

    note these boxes do not have a speedo drive so you will have to fit an electronic speedo,



    i have a 735i with a zf4 hp22 gearbox , when i start the engine it spurting oil out of the dipstick , the box have being o/haul by my self , could you give me advise please (1990)

  7. dave says:

    The first thing to check it that the breather is not blocked, on a 2 whel drive this is at the top of the rear housing,


  8. Sean Cawood says:

    Hi – I would wish to convert my 1998 300TDI Defender 110 from manual to autobox – I have the opportunity to aquire a P38 4.6 Overfinch gear / transfer box -
    1. Is it possible to mate this to the Defender 300TDI manual?
    2. This veh is to be used primarily as an Africa over land application – what sort of upgrades to strenghthen bullet proof the gear / transfer box, can be done & rough price point estimate?
    3. I understand the the bell housing would require modification – can you recommend where this can be done?
    4. Finally is this as strong / bullet proof as it (reasonably) gets for a gearbox for this vehichle?
    Many thanks for your help and assistance with the above,

  9. Dave says:


    The P38 V8 auto box is not suited for this conversion, it would be much easier to use the 300 tdi disco auto box,

    Make sure you use an oversize oil cooler as its often heat that causes these boxes to fail,


  10. mick says:


  11. WILLIAM MILLIN says:



  12. scott says:

    HI i have just bought a range rover p38 2.5 vouge and it struggles to change gear up hills it has a auto box it when you put your foot down nothing happens it feels like it is going to cut out.

    • Dave says:


      I would guess this is an engine fuelling issue, get this checked out first before you pull the gearbox


  13. Miles says:

    Hi Dave, I have a 1997 P38 4.6 on a dualfuel conversion. When it starts from cold it will only get up as far as 3rd gear for the first 5 miles or so, or until it’s fully warmed up. Pressing the ‘Sport’ button during this time solves the problem – it changes to 4th and then behaves properly. I love the car but if it needs a new gearbox it’ll probably be the end of our relationship! Any ideas?

    Many thanks!


    • Dave says:


      Are you sure you are not confusing 4th with the converter lockup, the converter locking will feel like a gear shift but the ecu will only lock it when the engine is warm,


      • Miles says:

        Thanks Dave, but the revs drop by 600 when I press the sport button – that’s why I’m assuming that it’s refusing to engage 4th until it’s done 5 or 6 miles. It’s as though it’s starting in Sport mode every time but pressing the button sets it back to normal gearbox operation.

  14. ian hibbeard says:

    i have a 1997 p38 diesel rr and i am having probs with my automatic gearbox,when i am driving it is like the clutch is slipping and wont change gears,i have checked the oil inthe gearbox which is below the bottom mark on the dipstick,also when i turn engine off/then on it will go again but then start slipping..any ideas

    • Dave says:


      I would suggest topping up the oil level and trying it, if it still slips then the clutch packs are too far gone, it will need the box changing,


  15. John Monk says:

    Hi Dave.

    I have an Auto D2 and have a whine in first and second but it seems to go when the auto box shifts to 3rd. I have tried it in manual mode low range and get the same thing…..any idea’s if it the auto box or transfer box?

    Thank you.


    • Dave says:

      the transfer case would whine in all gears but that said it’s very rare for the autobox to be noisy, you could try dropping the oil out to see if this gives any clues,


  16. Nigel says:

    Hi Dave, My Td5 D2 has lost its PRND321 on the LCD where the odometer is (odometer display is still there but no letter to indicate what gear is selected). Also missing (happened at the same time) is the ability to press the M/S button below the gear shifter and engage Sport Mode. No fault codes are logged and it behaves like it always has. I’d love to hear your suggestions. Cheers mate.

    • Dave says:


      Sorry but I am not very familiar with these type of electronic faults,

      Sorry I cannot help,


  17. Dave says:

    I think this is run from the BCM and gets the signal from the XY position switch on the side of the autobox,

    usually if the switch has a problem the M+S lights up and it goes to limp home,

    sorry I can’t be sure what doing this if it’s still driving OK,

  18. David Smart says:

    Hi Dave
    I have a 2003 Range Rover 3ltr auto. the problem is when I start it in the morning and engage drive the engine revs freely but the car only inches forward, slowly picking up speed,then after about 30 seconds all appears normal. This only happens from stone cold and is ok the rest of the day.
    I have tried replacing the gear oil and filter but this has made no notable difference.
    Any ideas?

  19. Mike Hall says:

    Hi Dave, having problems with the p38 diesel box, feels like its stuck in sports mode. Try low box and the box changes gear perfectly. I have disconnected the transfer motor and the problem gets better but not right as will not lock up the convertor and wont change into top until around 65 MPH. This is not good for the MPG. Tried oil and filter, both ECU’s Please help.

    • Dave says:

      Try another engine air flow meter, the AFM gives a load signal to the Autobox ecu and often cause this issue,


  20. Spike says:

    Have a Disco II 2002, and can’t select sport mode (no indication on dash either), and it is intermittent to lock up in 4th.
    Any ideas ??
    Ta muchly


    • Dave says:

      Not sure,

      Converter should lock when warm, if not if could be a valve body fault,


  21. Nuno Pinto says:

    Hi Dave,

    on my RR P38 diesel autobox 4hp22, latelly, when it reaches aprox 80 kmh the converter locks up as normally, but as i continue to accelerate it unlocks, than locks, than unlocks…..sometimes it stays locked but more often it stays erratic locking like its upshifting and downshifting….other than that it drives normally in all gears..Already changed oil with fresh ATFDIII, but still the issue persists….

    Any advise?


    • Dave says:

      I have seen this once before and we tried another Autobox ecu which fixed it,


      • Nuno Pinto says:

        Thanks Dave,

        Oddly this happened a couple of times, and one moment stopped doing it, it has been fine since. I guess you’re right, it must be electronics….if it happens again i’ll try it.


  22. Glen Harding says:

    Hi my range rover classic 1991 automatic box makes a very loud thud of a noise (can be heard from at least 6 feet away ) when i select reverse gear ,i find when first started from cold the noise is not as apparent ?? only when warmed up and selecting reverse .

    Kind Regards

    • Dave says:

      That’s just because the oil is thicker when cold,

      The clunk will be the slack in the transfer case, chain etc,

      There are no adjustments on the Autobox to make it shift softer other than slackening off the kick down cable but this will also affect the shift pattern,



  23. Kim Olesen says:

    I have a RR sport TDv8 2007 the problem is that my auto geax box periodically connects very violently when the car is stationary and I start again ..!?
    Good advice? Converter error? gear box flush and new oil and additive?


  24. Ivar says:

    Have 97 a 300TDi Auto ithe ECU. Will a TD5 auto box fit?

    • Dave says:


      The 300 Autobox is hydraulic not electronic, the td5 box is electronic, they are not compatible,


  25. paul walls says:

    i have a n reg p 38 range rover had gearbox done and have fault on dashboard saying gearbox overheating see owners handbook slow 35 miles per hour looks like limp mode

    • Dave says:


      The temp sensor is fitted to the oil cooler not in the Autobox, the sensors are often faulty when the warning lights come on as opposed to being an Autobox problem, try changing his sensor,


  26. Steve White says:

    I am looking into a conversion project on a Series Defender. I want to mate a ZF4HP22 or MT82 6speed transmission to a Ford engine. I would think that only a V6 or 4 cylinder would fit into the Defender. I know that a 2.2L Ford Duratorq (“Puma”) Diesel will fit as will a 3.2L Power Stroke diesel used on the Ford Transit.

    Because the Defender will be used in the United States, I’m looking for engine options that are already available in the U.S.

    Thank you very much for your advise.

    • Dave says:


      It’s possible to fit a 2.2/2.4/3.2 with the MT82 but it will not be easy on cheap,

      It will be far easier and cheaper to fit a 300 tdi with either the 4hp22 or 5 speed R380,


  27. Martin Eyre says:

    Hi, are you familiar with the ZF 4HP20 box? Well if you do here is my problem my box doesn’t like the cold if I run it straight from a cold start when it changes from 1st to second the engine will rev quite high and 2nd will engage with a clunk sometimes when running in 3rd or 4th there will be a big lurch and a clunk and then I get an auto gearbox fault come up on my dash (Citroen C5 2l SX Auto 2004) and it then goes into limp mode, now if I stop the car and re start the fault clears and the gearbox operates normally, this has been going on for some time and is gradually getting worse, any ideas?

    Thank you.

  28. Michael says:

    Hi there
    I have a 2000 td5 discovery auto and have a constant whine in all gears (including park/neutral) as if gearbox has no fluid but car drives with no problems at all car does not have ace and fluid is at the right level. Stall test sat just under 2800 rpm. The sound is defiantly from the box and is there when car is stopped and in motion.
    Your help would be greatly appreciated,
    Thanks in advance Michael

  29. keith paterson says:

    just an update been reading up and there is talk about alternator problems causing odd problems tested battery with all in one type tester and battery is fine but alternator was not making it to green was charging but not at full power could this be problem
    thanks keith

  30. ian says:

    hi – i have a p38 4.6 engine with a 4hp-24 gearbox – i want to put this in to my classic shaped range rover kit / buggy that has classic axles. what transfer box can i fit to this to get it to work – the P38 transfer box has the drive on the wrong side – cani fitr a discovery transfer box ?????

  31. john says:

    Hi we have just bought a p38 and it will not drive in the drive position, but will go when we put it in to 1 , 2 and drive off then into drive it then works. please could yould you tell us is this a costly repaire. thank you for your time john.

  32. john says:

    Hi me again its a p38 4.6 ltr we now have problems with the air suspension it wont rise , would this contrabute to the gear box not working in drive ?? . once again thank you for your time regards john.

  33. adolf says:

    I have installed a exchange zf 4hp22 electron. transm. problem is the ubschift in to 2 gear. hard schift when cold… normal schft when eng is warmed up. thanks adi.

  34. justin says:

    Hi Dave, i have a 99 td5 discovery, lately it flares between 2nd and 3rd and when its cold for the first minute or so after startup it seems like your trying to drive with the handbrake on. Any ideas? And would it be possible to replace the internals of my trans with that of a 4hp22 from a BMW? Cheers

  35. stuart kirkwood says:

    Hi Dave Just got a rover P5B 1972 automatic box. Been driving using D/N/R/P most of the time, decided to use kickdown this time out, throttle got stuck down for 2/3 sec ( to long for comfort ) then decided to put box in to1st for over run going down a hill, got the bottom, then went to shift in revers..No movment could go back from N to D/2nd/1st and back to N but no R or P. What do think Dave. Stu

  36. Dazza says:

    Hi ya all i have a dt 2.5 p38 1999 when your driving and take your foot off throttle the revs drop to tick over and the engine stalls its like its a manual and you drop the clutch with the brakes on its just stalls and is qiute violent at times its also hanging on to gears and causing the viscous fan to cut in i replaced that and the new one has lasted a month now locked in all the time and engine sounds like a jet engine and is drinking fuel the engines is new to the car and out of a low milage 325 i bmw

  37. Russell Smith says:

    Hi How can I tell the difference between a Discovery 1 3.9 v8 autobox petrol and a diesel one? That is if there is any difference ?


  38. joe murphy says:

    1997 rlandange rover2.5 bmw engine was driving perfect parked vehicle in drive unable to get any gears and when I go into park it grindesn slightly like as though iy is stuck in neutral and on the dash it is saying neutral any ideas
    joe galway ire

  39. Stuart Inman says:

    Hello I have a v8 Discovery auto and when i put it into drive there is a lot of “creep” and the engine tries to stall once on the move everything is ok, the engine/gearbox unit was transplanted from a working disco so I am thinking that it is a set up issue.

  40. steve says:

    Hi I have a 2003 disco 2.5 diesel, it has been struggling to start the past 3 mornings as if the battery was flat. Eventually got it going, today having done a 40 mile motorway trip on my way back the manual and sport mode green indicators are constantly flashing and it was if I was losing power, Can you advise.

  41. andy gilbert says:

    I’ve got a problem with the auto gearbox on our 1995 4.0SE Range rover, it’s been running perfectly we have been away for a week and come to move it now and it wont engage any gears. When you move the stick from P to R or Drive it does nothing but will roll forward like it’s in neutral (the lights come on down the column as normal). when I put it back in P it graunches the gears like the clutch hasn’t engaged. There’s plenty of fluid in it, what else should I check?

  42. Peter Scholey says:

    Hi i have a R/rover 3 lt deisel 2004. done 75000 miles. I started the engin selected D it took a few seconds to engage but onec traveling the increase in rev’s had no effect on gear changing, infact drive stoped with reves up to 3.5k.

    Parked up about an hour. started the engine it pulled forward in drive and revers but only for a matter of seconds, then nothing. Any ideas of the problem with these syptons please?

  43. Will says:

    Hi I have an L322 Range Rover Vogue 2003. The car was very sluggish on cold start and then got to a point when it would not engage into drive unles reved to 2500rpm, then was fine all day till next morning. Had it flushed and new oil put in and it is maginally better wear by it now seems to engege and crawl along extremely slowly but still needs to be reved to about 2500rpm to move of properly. This has happened over the last couple of months, any advice appreciated?

  44. Peter Williams says:

    Hi, I have a 1992 Range Rover Classic. 146,000 miles. It sat for 3 or 4 years before putting it back on the road this year. After a few hundred miles back on the road the transmission would just “disengage” – like it was in natural. It didn’t have the feel of the clutches slipping – no power at all through the transmission. I stopped and was able to get it to move a few 10s of feet and then it would happen again. It eventually started working again and I made it home, but in 1st as it started not wanting to shift either. I drove it the next day as a test and it worked fine. Next day, it would not shift out of 1st, drove it back to my house – parked it. Any thoughts? Thanks

  45. jhon says:

    hi i have a landroverdiscovery 3 2.7 automatic yr 09 the gear box is great untill i tow with it after about 30 miles the car brings the f litgh on it goes when reset but only does it when towin ive changed me brack ligth swith no beter any help would be good thanks

  46. Lynn says:

    HI , I have a RR 4.6 auto. With engine running it wont go into gear and for P it just grauchies. Engine off all gears light up on control, no faults on dash. Top up oil. No gears at all. Any idea?

  47. John says:

    Hi have a td5 discovery 2, 02 plate, I have the two gear lights flashing. Have checked power to the transmission ecu, 12v there, the diagnostics show solenoid 1 and 2 oc/sc fault. Have changed the battery,topped up the gbox oil no change. Have checked the wiring from the ecu to the gbox all ok, checked it from oc ( broken wire) to short on the chassis all is ok. I know there are two solenoid s in the gbox, but I find it strange that both are showing the same fault.

  48. josh says:

    I just rebuilt my 4hp22 and I have all forward gears, engine braking in all forward gears. Reverse only works when cold. When cold reverse will go in and hold, but after a short drive reverse no longer kicks in. I swapped the reverse gear safety valve and no change still. Any ideas?

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