Advertise on fullfatrr.com »

Home > Technical (L322) > ZF5HP 24 Gearbox - Delayed and harsh engagement
Post Reply  Down to end
Page 1 of 1
Print this entire topic · 
steve k



Member Since: 05 Apr 2024
Location: Berkshire
Posts: 58

United Kingdom 2003 Range Rover HSE Td6 Giverny Green
ZF5HP 24 Gearbox - Delayed and harsh engagement

I have only recently purchased the car 2004 4.4M62 with the ZF box knowing fully that it had a gearbox problem so I am in the process of working through the fault. The car is not MOTd so not able to road test but low range works and from a brief slow speed drive around the property gears change o.k. using the steptronic function.

On a cold start the gearbox engages drive as expected. No harsh thump. Once the engine and gearbox get warm drive engagement takes up to 2 seconds and is a harsh thump followed by a second thump. I have seen reports of this fault but nothing definitive on the cause being in the valve body or in the main body.

I first checked oil level at correct temperature and there was a thin stream of oil emerging. I do not have the IID 2 GAP tool so used a software tool called BMW Scanner 1.4 but I would not want to rely on the code descriptions too heavily. Its an o.k. tool for BMWs but for range rover it does not provide full functionality. Anyway I get that it needs a proper ODB tool at some point.

The fault descriptions were: Stalling speed, Gear check 3, Gear check 2, Gearbox switch

I have dropped the sump and its been off before as had the valve bodies. No swarf, filter opened up and clean inside. The only anomaly I could find was that two springs could have been in the wrong valve locations in the lower rear body. This is based on photos that RRPhil provided on another post for a different problem. I transposed both springs SV1 and SV3 with SV3 now being the shorter spring and have refitted and refilled with no change on the fault.

All the solenoids and speed sensors and temperature sensor are within the spec's I have found for resistance and with basic voltage tests on the solenoids they all make the same sound for the two variants fitted. I have cleared the error codes and currently there are no codes but the car is still up on stands so not driveable.

Without full ODB connectivity I cannot reset adaptations in case the gearbox was repaired previously as mentioned the sump and valve body has been off before, and this was not carried out to reset the behaviour - that would be nice to hope for!

The oil that came out was probably the wrong type being dark red. I re-filled using straw coloured oil from Westway lubricants as per the photo. It took about 7 litres before streaming at correct temperature.

The battery is not good, it starts fine but voltage drop during cranking and as soon as the engine shuts off shows probably one duff cell so I have ordered a new battery. I mention the battery because I know from experience that BMW electronics are very sensitive to voltage drop on start up causing issues and need to eliminate this.

Any pointers/suggestions most welcome please. I'm in the process of also dealing with other usual problems with these cars so it likely to be up on stands for a while yet

Click image to enlarge
 Current: 2003 TD6 HSE
2004 Vogue SE 4.4
Previous: 1993 Classic 3.9

Post #723562 28th Aug 2025 10:44am
View user's profile Send private message View poster's gallery Reply with quote
Dolphinboy



Member Since: 08 Dec 2009
Location: Bristol
Posts: 3252

United Kingdom 2016 Range Rover Autobiography SDV8 Baltic Blue

RRPhil is the God of these gearboxes on here. I am sure he will be along to offer some sage advice.

Last edited by Dolphinboy on 29th Aug 2025 4:51pm. Edited 1 time in total

Post #723573 28th Aug 2025 4:22pm
View user's profile Send private message View poster's gallery Reply with quote
RRPhil



Member Since: 22 Aug 2011
Location: Blackburn, Lancashire
Posts: 1026

United Kingdom 
Re: ZF5HP 24 Gearbox - Delayed and harsh engagement

steve k wrote:
Once the engine and gearbox get warm drive engagement takes up to 2 seconds and is a harsh thump followed by a second thump.

Does this result in the TRANS. FAILSAFE PROG warning being displayed in the message centre?

Phil

Post #723575 28th Aug 2025 7:02pm
View user's profile Send private message View poster's gallery Reply with quote
steve k



Member Since: 05 Apr 2024
Location: Berkshire
Posts: 58

United Kingdom 2003 Range Rover HSE Td6 Giverny Green

Hello Phil, many thanks for you question. No warning messages relating to the gearbox upon taking delivery or since doing the work so far. The car was delivered on a recovery and I have only been able to drive it around a small paddock before putting it up on stands so possibly its not been driven enough?

What I can also add is that an hour ago I checked the wiring continuity from the gearbox ECU to the relevant solenoids used for 1st gear based on my understanding of how RAVE explains the operation in a chart of which solenoids are activated dependent on the gear selected: SV1 and EPRS1,2,3 & 5.

All checked out with expected resistance values except EPRS1 which is open circuit. I can confirm from unplugging the connector at the gearbox and checking the loom that there is continuity between the ECU and the gearbox connector. I am using RAVE circuit diagrams for reference.

Although I meter checked and voltage checked all solenoids I only did a visual inspection of the loom inside the box. I was careful during valve block install by fitting the loom/connector separate from the valve body so as not to risk any undue stress and remember plugging all the solenoids etc in but regardless the same fault exists so its possible it was damaged during the previous work done. Unless I'm missing something I will need to drop the sump again to sort out the break but most importantly could this solenoid that I believe regulates the main system pressure be a silver bullet fix?? Current: 2003 TD6 HSE
2004 Vogue SE 4.4
Previous: 1993 Classic 3.9

Post #723576 28th Aug 2025 7:22pm
View user's profile Send private message View poster's gallery Reply with quote
RRPhil



Member Since: 22 Aug 2011
Location: Blackburn, Lancashire
Posts: 1026

United Kingdom 

So, just to confirm, if you measure the resistance between pins 2 and 16 at the 16-pin connector you get an open circuit?


The EDS 1 (or EPRS1) solenoid controls the mains pressure in the transmission, via the modulation valve, and produces maximum mains pressure when there is no current fed to it.

Click image to enlarge




Normally, during drive engagement, the solenoid would be operating at full current to modulate the mains pressure down to around 6 bar. If it is receiving no current (because the wiring is broken) then this will double the transmission hydraulic pressure to around 12 bar, and also prevent the A & C clutch accumulators from doing their job of smoothing the clutch engagements when stationary. The pressures are higher still in Reverse as the torque reaction on the F-brake is additive.



This may explain some of the symptoms that you are experiencing (harsh engagement when warm) but still doesn’t explain some of the fault codes that you’ve recorded. Anyway, one step at a time.

Phil

Post #723592 29th Aug 2025 11:10am
View user's profile Send private message View poster's gallery Reply with quote
steve k



Member Since: 05 Apr 2024
Location: Berkshire
Posts: 58

United Kingdom 2003 Range Rover HSE Td6 Giverny Green

Hi Phil

unfortunately I cannot get a reliable test under the car as access and visibility is bad, even with clip leads and probes I cannot be certain on test result. What I can confirm is that with the gearbox connector in place I get expected 6 Ohms when probing ECU pin 21 (gearbox pin 16) and ECU pin 28 (gearbox pin 2)

RAVE conflicts with the ZF intel' I have and its causing me a lot of confusion at the moment. RAVE does not include the internal linking of wires that the ZF schematic does and my test results on all solenoids do not make sense. It implies a break somewhere when testing via gearbox pin 12 but the same solenoids tested via gearbox pin 16 provide resistance values as expected. Either RAVE and/or the ZF schematic are not accurate or I'm not reading my results correct. I resorted to putting them into a spreadsheet as something isnt making sense to me.


Click image to enlarge


Click image to enlarge
 Current: 2003 TD6 HSE
2004 Vogue SE 4.4
Previous: 1993 Classic 3.9

Post #723600 29th Aug 2025 1:53pm
View user's profile Send private message View poster's gallery Reply with quote
RRPhil



Member Since: 22 Aug 2011
Location: Blackburn, Lancashire
Posts: 1026

United Kingdom 

Accessing the 16-pin plug is a pain. I made up this little breakout board to make it easier to read of the resistances.



That ATSG drawing used to bother me because they have the solenoid order the wrong way round. I wrote to them in the end, and they published a correction.


The wiring shown on the ATSG sheet is wrong, too. Pin 16 is the power feed for the three MV on-off solenoids as well as EDS1 & EDS4. Pin 12 is the power feed for EDS2, EDS3 & EDS5. RAVE has this correct.


Phil

Post #723609 29th Aug 2025 3:38pm
View user's profile Send private message View poster's gallery Reply with quote
steve k



Member Since: 05 Apr 2024
Location: Berkshire
Posts: 58

United Kingdom 2003 Range Rover HSE Td6 Giverny Green

Wow - blimey! many thanks. I will compare the correct wiring to my results and see where it leads. This is very helpful Phil - Current: 2003 TD6 HSE
2004 Vogue SE 4.4
Previous: 1993 Classic 3.9

Post #723610 29th Aug 2025 3:43pm
View user's profile Send private message View poster's gallery Reply with quote
steve k



Member Since: 05 Apr 2024
Location: Berkshire
Posts: 58

United Kingdom 2003 Range Rover HSE Td6 Giverny Green

With the proper wiring diagrams I have re-checked the connections from the ECU box down into the box and back my results confirm the internal gearbox wiring is faultless.

Without your very helpful and invaluable information Phil I would be chasing a non existent wiring fault!

I ran the engine and it takes around 15 minutes of idling and gear selecting before it started to become harsh when engaging drive. Reverse did not give any concerning thump, just forward drive. The car is still up on the stands though.

Clearly I need some realtime OBD data to help understand what might be going wrong but I'm loath to shell out £500 for IID tool just yet. Current: 2003 TD6 HSE
2004 Vogue SE 4.4
Previous: 1993 Classic 3.9

Post #723614 29th Aug 2025 6:17pm
View user's profile Send private message View poster's gallery Post Reply
Post Reply  Back to top
Page 1 of 1
All times are GMT + 1 Hour

Jump to  
Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2006-2025 Futuranet Ltd & Martin Lewis
fullfatrr.com RSS Feed - All Forums


Switch to Mobile site