ZF 4HP22 Troubleshoot - solved

[Insomniak]

Morning all,

I'll give the full details but there will be a TLDR version below

Yesterday I was driving and my alternator serpentine snapped, I stopped the car in a near by gas station. The next day I pickup new alternator and power steering serpentine belt, I replaced them. On my way back home I noticed that while I was cruising on the highway at 110 km/h (68 mph) the car was trying to downshift sporadically, not knowing better I kept driving. About 20-30 minutes later when I got off the highway my transmission was slipping until 4000-4500 rpm before engaging and very weakly moving the car. Is there anything that comes to mind for fixing this? I got a quote for a refurbished 4HP22 from an authorized ZF dealer and it's about 1900-2100$ which is pricy.

TLDR: transmission is slipping at 4000-4500rpm where should I start my diagnostic

Thank you all in advance

[CroughtonE32]

Smarter minds here are going to have to help you with testing and a possible fix, but I can tell you the price you're getting for a rebuilt 4HP22 is good. More than 10 years ago at about 110,000 miles my transmission lost top gear. It would only shift 1-3. Twenty two hundred installed was the price I paid at the dealership for a swap. Pulled mine and took one off the shelf. Took about six hours. Friends said I spent too much money by going to the dealer, but here we are maybe 11 or 12 years later and you're getting the same quote from a ZF shop. If you can't get it fixed, don't think your pricing is bad. Good luck with this.

[Insomniak]

Yeah exactly it’s going for 2999$ but they’re giving me a 1000$ core credit for the old one that’s without installation but it’d be a permanent fix indeed !

[shogun]

ever changed the ATF and the ATF filter? Also when changing ATF and filter, one can "read" in the ATF pan what is wrong. Does the ATF smell burnt? Do you see any large metal parts on the pan magnets? etc pp.
One can flush the transmission https://www.bimmerforums.com/forum/s...ns-flush-setup
Clean the filter screen in front of pressure valve https://www.bimmerforums.com/forum/s...hifting-solved

First thing to do is checking the fluid level and that is quickly done.
4HP22/24 with dipstick and filling from top thru dipstick pipe: 1988 E32 owners manual states on page 63: automatic transmission, checking oil level: the car must be standing on a level surface with the transmission at operating temperature 80 degree Celsius. Allow the engine to idle with the selector lever at P or N. Pull out the dipstick, wipe it with a non-fluffy cloth and push it back to measure the oil level. It must be between the two notch marks.
The quantity of oil represented by the space between the two marks on the dipstick is approx. 0.3 liter when the transmission is at operating temperature. If necessary, add fresh ATF at the oil level check pipe.

Anything else damaged when the alternator serpentine belt snapped? Check also the crankshaft position sensor if there is a wire damaged, the transmission used the crankshaft position sensor to record the input shaft speed, there is another sensor inside the transmission for the output speed.
CPS testing by Bentley Publishers
Using digital multimeter, check resistance between terminals 1 and 2 in crankshaft position/rpm sensor connector.

Crankshaft Position/rpm Sensor Specifications
• Coil resistance (approx.) @ 20°C . . . . . . 540 ± 10% Ω
• Air gap (sensor distance from toothed wheel) . . . . . . . 1.0 ± 0.3 mm (0.04 ± 0.01 in.)
download this https://bentleypubs.atlassian.net/wi...specifications

Fluid pressure regulation in the hydraulic ZF transmissions is controlled by a combination of spring pressure and modulator pressure. In the electronic ZF MV5 controls mainline pressure to a degree not possible with hydraulics alone. The electronics allow almost an unlimited range of pressures from very low during light throttle shifts to maximum pressure during hard acceleration. Operation of the solenoid MV5 is described on the next page 17
The simplified illustration below shows the pressure regulator solenoid. The solenoid is sprung normally closed. When power is applied the valve opens and some of the mainline pressure bleeds off through the vent reducing actual working pressure. Maximum pressure occurs with the valve deenergized or close. The pressure regulator solenoid is adaptive and over time will adjust mainline pressure to suit driving style. Sedate driving habits will result in lower pressures than aggressive driving. Lower pressures improve shift qualities but can result in slippage. The ECM constantly monitors clutch slip time and adjusts the pressure accordingly (the ECM is programmed with an '"ideal" nominal time). This not only accounts for driving style but also for clutch wear http://bee.mif.pg.gda.pl/ciasteczkow...p22/4HP_22.pdf

see also my website the fault finding table ZF 4HP22/24 http://twrite.org/shogunnew/diagnosis/gearbox.html

[Insomniak]

Thank you as always for this in depth answer!

I knew service was due , I purchased BMW transmission fluid and filter about two weeks ago!

I’ll follow all the steps you’re suggesting for some reason I believed I burned my clutch pack but it may be recoverable.

Thank you a thousand times !

[Annddrriy]

when the car was trying to downshift sporadically did you see road go to up hill ?

[Annddrriy]

When you did flush of transmission how many seconds takes oil to suck from white canister where hose connected to the bottom while you are shifting the gears ? When canister is empty needs to stop engine immediately or refill ATF more and keep shifting a bit more time ?

[shogun]

when you start the engine and set the gear, the Oil pump for the automatic transmission ZF 4HP22 ZF 4HP24 ZF 4HP24A 10434190571 will immediately start to suck fluid as it is a gear type, the volume depends on which gear is selected, RPM, temperature of the ATF etc. Number of teeth of small gear - 12, Number of teeth of big gear - 15, The inner diameter of small gear - 32.5 mm. The outer diameter of large gear - 88 mm.
Make sure that the canister where the pump sucks is never empty, continue flushing to clear fluid splashed out of the transmission.

[Insomniak]

when the car was trying to downshift sporadically did you see road go to up hill ?

I was driving on flat highway

When you did flush of transmission how many seconds takes oil to suck from white canister where hose connected to the bottom while you are shifting the gears ? When canister is empty needs to stop engine immediately or refill ATF more and keep shifting a bit more time ?

I didn't flush it yet most likely by the end of the week since I need 9 quarts according to the post that shogun shared

- - - Updated - - -

when you start the engine and set the gear, the Oil pump for the automatic transmission ZF 4HP22 ZF 4HP24 ZF 4HP24A 10434190571 will immediately start to suck fluid as it is a gear type, the volume depends on which gear is selected, RPM, temperature of the ATF etc. Number of teeth of small gear - 12, Number of teeth of big gear - 15, The inner diameter of small gear - 32.5 mm. The outer diameter of large gear - 88 mm.
Make sure that the canister where the pump sucks is never empty, continue flushing to clear fluid splashed out of the transmission.

I went today to check on it quickly because I thought of something, I purchased the car from a 73 year old man. The mechanical shop he was bringing to with was far from good, this BWM had fluid & parts that were out of OEM specs. This is where I'm fairly sure that I'm right but, when you check the fluid level on a transmission to my knowledge you have to bring it to operating temp before doing so, when I did that there was too much fluid in the transmission

https://ibb.co/SQkpdJn (the level was almost above the black stick)
https://ibb.co/0YgWQYM (color looks fine)

I believe the person who service it before me did the service without bringing it to operating temps because the color of the fluid is good but the volume is way too high.

Also is Liqui Moly Top Tec 1200 ATF is on spec with BMWs? since I need a larger volume for a full flush I'd go with this one.

Thank you

[shogun]

if it is above the max level in cold condition, then too much ATF is in the trans http://www.europeantransmission.com/...MWtechinfo.htm same like too low level, too high level causes foaming and slipping.
Color of the ATF looks good. Maybe you do not need a flush at all, just fix the ATF level and test drive it.
What you can do is to test all the solenoids and the output speed sensor inside the valve body, for that remove the electrical plug on the transmission side and test them, details and specs here http://www.bmwe34.net/E34main/Troubl...ch%20Guide.pdf
if the speed sensor is not working properly, then the trans plays crazy
Liqui Moly Top Tec ATF 1200 is fine for your car, good product https://www.fcpeuro.com/products/aut...i-moly#fitment

Is the speedometer fluctuating? http://www.bmwe34.net/E34main/Mainte...eed_sensor.htm

[Insomniak]

Couple days later , I went today and service the transmission (oil + filter)

Problem persists , there was a lot of darker thicker black fluid on the magnet at the bottom of the oil pan.

There was metallic shavings inside the old filter

1st gear is fine

2-3 are slipping still

The transmissions holds the 1st gear as long as I give it gas even if its 5% pressure on the gas pedal when I let it go it shifts but 2nd gear slips a lot.

I believe it has to do with the clutch pack correct me if I’m wrong

[Annddrriy]

If second gear slips a lot then the clutch pack of forward gear is gone together with E clutch pack. The E clutch pack drum gives the torque to output shaft. My car had same problem as yours but mine had third gear was slipping a lot. Automatic Transmission Mechanic rebuilded with 1 year waranty or 30.000km.

[shogun]

darker, thicker black fluid on the magnets in the ATF pan is normal, that are abrasive parts collected there.
Metallic shavings in the old filter: small particles? Like 1-2 mm? Also this can happen, when there are bigger particles, then you have to worry.
Go thru the fault finding table on my website for the 4HP22/24 http://twrite.org/shogunnew/diagnosis/gearbox.html
Test the solenoids and speed sensor of the valve body

[whiskychaser]

Follow Shogun's list from the post above. Then maybe check the table below. It may help you identify which, if any, clutch is faulty so you may be able to concentrate on that. What current fault codes do you have in the TCM?
img155.jpg

[Insomniak]

I don’t have any visible code on the cluster and no tools to read the TCM if there is

[shogun]

test all the solenoids and the output speed sensor inside the valve body, for that remove the electrical plug on the transmission side and test them, details and specs see my post and list above

[Insomniak]

Yeah it’s currently in a shop near by to have it remove from the car I don’t have a lift kind of a tough job on jack stands

Once removed I’ll bring it back home and work on it thanks for the documentation really appreciate it !

I’ll keep y’all posted

[Insomniak]

test all the solenoids and the output speed sensor inside the valve body, for that remove the electrical plug on the transmission side and test them, details and specs see my post and list above

For the time being I found a 4hp22 from an E30 do you know if it’s a direct bolt-on?

S/N : WBAAA2305H8260185

Also here are some pictures of the filter

https://imgur.com/a/0sTfIRk

And the car is currently getting diagnose first estimate I got for a complete rebuild was 4500$ which is way too expensive im not willing to invest that much currently


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[shogun]

The E30 was built in 1987 and that transmission was built till July 1988 http://bmwfans.info/parts-catalog/E3...mission_4hp22/ I have my doubts it will be a direct fit.
$4500 is too expensive, for example European Transmissions has reman 4HP22 for $2850.00, their ad says Market price: $5650.00, you save $2800.00 50% less https://europeantransmissions.com/bm...sion-730i.html
But as you mentioned: "I got a quote for a refurbished 4HP22 from an authorized ZF dealer and it's about 1900-2100$". That is a good price. Check around, if there is a specialist shop in your local area which repairs ZF transmissions.
the metal particles in the filter are not too big, but something wrong, could be from metal/metal friction of the clutch plates where the clutch plate friction material is gone.
Or try a DIY repair, disassemble, check what has to be replaced and buy the parts. But takes more time and you are not sure if the repair is successful till it is installed and test driven.
Easiest would be to get a reman or your trans is repaired by a pro shop.

[whiteghost1]

For the time being I found a 4hp22 from an E30 do you know if it’s a direct bolt-on?

S/N : WBAAA2305H8260185

Also here are some pictures of the filter

https://imgur.com/a/0sTfIRk

And the car is currently getting diagnose first estimate I got for a complete rebuild was 4500$ which is way too expensive im not willing to invest that much currently


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The bellhousing for the 4HP22 used in the E30/M20 is different than the bellhousing used in the E32/M30, so that tranny is not compatible with your car

[Insomniak]

The bellhousing for the 4HP22 used in the E30/M20 is different than the bellhousing used in the E32/M30, so that tranny is not compatible with your car

That’s what I figured I’m no mechanical expert but let say I would take the bell housing from my m30 and swap it with the M20 would it fit ? Is it even possible ?

There’s only one 4hp22 within 600km range from me and I’ll have to be creative to find one I believe


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[Cactuar]

There are some 4HP22 transmissions from salvage yards in Canada for 735i models.
I can't link to the search results, but make your own search here: https://www.car-part.com/index.htm

This is the results I see. Getting one from Quebec or Ontario would be much better than rebuilding one for 4500$.
Capture.JPG

[Insomniak]

Thank you !!!
Will definitely look into it.
This makes me realize there a 7 pin and a 8 pin connector for the TCU anybody knows how to tell which one I have ?

1988/03 735i

[shogun]

count the pins on the trans plug, most probably an 8-pin, my 11/88 750 also has 8-pins, here are the details http://www.bmwe34.net/E34main/Troubl...ch%20Guide.pdf

Three different versions of valve bodies have been used on BMW vehicles, with minor differences between them

The 1st version,designated Early "E-7", has 5 solenoids on the valve body, was introduced in 1986 and used up thru 1989. This version includes a solenoid for reverse lockout.
The 2nd version,designated Late "E-7", has 5 solenoids on the valve body, was introduced in 1988 and used up thru Mid-1989. This version includes a solenoid for reverse lockout.
The 3rd version,designated "E-9", has 4 solenoids on the valve body, was introduced in Mid-1989 and used up thru 1994. This version uses a shift solenoid for the reverse lockout function.

You can count the pins on the transmission connector. I assume you have a 2nd Version, Late "E-7", 5 Solenoid.
Also note down all details which are mentioned on the side of the transmission above the ATF pan on the ZF identification tag, there is mentioned the type 4HP22, the serial number and the Stucklistennummer = parts list number.
Ideal would be to get a transmission with the same Stucklistennummer, otherwise you might need also a new transmission control module = the one from the new transmission.

Stucklistennummer is called in English MAIN PARTS LIST. Check the main parts list on your car and then check here which main parts list could replace yours.
Here you have all the details , Possibility of substitution by.... https://zf-belarus.by/upload/pdf/cat2017.pdf
(no responsibility is taken for the correctness of this information)

[Insomniak]

Update #1

The garage where I sent it to have a second opinion on the transmission called yesterday, he said that the way the transmission shifts erratically that the TCM and/or the harness has to be checked before doing anything else.

Yesterday I removed my TCM

(http://bmwe32.masscom.net/johan/elec...s/modules.html)

https://imgur.com/a/qlQM9Uf

I opened it up but it was as clean as when it left the factory 34 years ago.

When I put it back in the car I forgot to plug back power section of the harness and went for a test drive , I immediately noticed the car was shifting much better.

I ended up ordering another TCM yesterday and I’ll swap them to make sure it’s not the TCM.

The day before this whole transmission issue started my alternator serpentine’s snapped , I’m thinking could the voltage fluctuation fried something ?


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