Hi all.

Isn’t it frustrating when you find your problem on a forum and the thread closes without a resolution?

Well that’s me right now and I’m hoping that one of you kind souls could point me in the right direction. If I do manage to fix it, I promise I’ll update here with the resolution!

The trouble code read out is shown in the picture. The symptoms are weird:

- started after a transmission oil change
- only happens after at least 30 mins driving
- usually bongs after a fast motorway run as I hit stop-start traffic
- it flashes up ‘transmission fault - limited gears only’
- occasionally the yellow EML comes on
- if I stop and re-start the car, everything re sets and all is well for the rest of the journey
- if I just clear the fault with GAP IID without turning off the ignition, the fault will recur

Other than this the gearbox is smooth as silk though just before the fault occurs, I may get a harsh change at low speed.

2007 4.2sc 119k

Has anyone experienced this before? Any suggestions on where to start on rectification would be much appreciated.

Thank you!

Quite surprised not to have prompted a response as yet…is this a rare fault? Des

2005 (2006 MY) L322 4.2sc Java Black, 2010 facelift conversion
1965 Lenham Lemans GT 1310 , Gulf Racing blue, FIA spec and road legal
2018 F56 Mini JCW, Thunder Grey/Black, Mulgari St2 tuned, FMIC, short shifter and Eibach springs

RRphil is the gearbox specialist on here. His word is legend.

He may be on holiday so be patient and he may appear.

If it only started after a transmission service, is it definitely the correct oil that was put in it and has the level has been set properly?

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2012 Range Rover 5.0 SC Autobiography in Indus Silver with Jet/Ivory Interior
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Thank you both. Fingers crossed RR Phil sees my post and is prompted to comment.

@david, yes the service was performed by a Land Rover specialist where the owner drives exactly the same car. I have no doubt they used the correct fluid. When the fault first occurred I went back to him and he checked the level. At that point the fault had cleared by re starting the car and no codes were showing.

I will take it back again now that I’ve got this fault code but it’s a bit of a trek to get there and I can’t do without the car at the moment. If I can check or do something myself I will…I just don’t know where to start. Just to know whether it’s an electrical or mechanical fault would be good! Des

2005 (2006 MY) L322 4.2sc Java Black, 2010 facelift conversion
1965 Lenham Lemans GT 1310 , Gulf Racing blue, FIA spec and road legal
2018 F56 Mini JCW, Thunder Grey/Black, Mulgari St2 tuned, FMIC, short shifter and Eibach springs

Of all the gearshifts, the 3-4 upshift is certainly the most common issue with the 6HP26X in the L322 (followed by the 2-1 roll-out shift). Part of the reason, I suspect, is due to the fact that the torque converter lock-up clutch is timed to engage its ‘controlled slip’ mode just before the 3-4 shift, which can make it difficult to differentiate between the two events i.e. LUC activation and the gearshift. The lock-up clutch is engaged in a very lazy way over a period of 2 seconds or so.

We know, after all these years, that by far the most common cause of faults with the 6HP26X is the solenoids. The temptation, therefore, is to recommend you replace the solenoids, reset the adaptions, and then evaluate the shifts again. Of course, while you’re in there you might as well replace the bridge seal, the four jump tubes, the connector sleeve, the sump pan/filter and the fluid. Problem is, this lot will set you back around £600 for genuine ZF parts, which is a lot of money to spend if it turns out not to be the cause.

Your symptoms are curious e.g. it takes half-an-hour of driving before the problem develops. Seeing as you already own an IIDTool, one possibility is to monitor the live data so that it can be analysed to determine exactly what’s going on. For example, one of the graphs below shows the torque converter LUC engagement and the other shows the events taking place during the 3-4 shift i.e. the B-clutch coming off and the E-clutch going on. As it takes 30 minutes for your problem to develop, though, I don’t know what the chances are of you catching the actual event that triggers the fault?





You’re absolutely right, though. Considering it is such a common problem there’s practically no conclusive evidence on the forums (that I can find) as to the actual cause.

Phil

Wow thank you so much @rrPhil. I really appreciate it.

Even more weird is that I could drive on the motorway for over an hour, do stop go in traffic for 20 mins and only then does the fault occur. And many times it doesn’t happen at all. It’s very frustrating.

I did try monitoring Live values but only the solenoids on/off and pressure values. There was nothing untoward happening that I could see when the fault occurred.

I’ll set it off to monitor the values you’ve provided and let’s see what happens.

Once again, thank you so much for your insight. It’s very much appreciated. Des

2005 (2006 MY) L322 4.2sc Java Black, 2010 facelift conversion
1965 Lenham Lemans GT 1310 , Gulf Racing blue, FIA spec and road legal
2018 F56 Mini JCW, Thunder Grey/Black, Mulgari St2 tuned, FMIC, short shifter and Eibach springs

You were right @RRPhil. It’s very hard to catch the fault occurring!

I was out for about 50 mins in town traffic today…GAP IID running live readings. I’d parked (briefly) twice in that time and re started the tool each time I set off again. About 5 mins into the next leg ‘bong’ Transmission Fault, Limited Gears Only. And the toll wasn’t running. Doh!

One thing I forgot to mention: it sticks in 3rd gear. Not 1-3, just 3rd. That might be relevant and then again, might not! Des

2005 (2006 MY) L322 4.2sc Java Black, 2010 facelift conversion
1965 Lenham Lemans GT 1310 , Gulf Racing blue, FIA spec and road legal
2018 F56 Mini JCW, Thunder Grey/Black, Mulgari St2 tuned, FMIC, short shifter and Eibach springs

Quote:

it sticks in 3rd gear. Not 1-3, just 3rd

That could be indicative of a worn rear stator bush, allowing the E-clutch hydraulic circuit to leak & lose pressure. The E-clutch is used in 4th, 5th & 6th gears and the control system inhibits shifting into any of these higher gears to protect the clutch from excessive slip. 1st, 2nd & 3rd gears, meanwhile, work fine.

Click image to enlarge

Phil

It could be that but when the bong occurs I lose 1st and 2nd gears too. Would that still point to it being this issue?

What’s most baffling is that recycling the ignition cures the fault and I go back to the smoothest gear changes imaginable. Des

2005 (2006 MY) L322 4.2sc Java Black, 2010 facelift conversion
1965 Lenham Lemans GT 1310 , Gulf Racing blue, FIA spec and road legal
2018 F56 Mini JCW, Thunder Grey/Black, Mulgari St2 tuned, FMIC, short shifter and Eibach springs

The bong probably indicates the transmission going into failsafe, which will lock the transmission in 3rd gear until the ignition is cycled. There’s nothing that’s conclusive with your symptoms but, if the stator bush is leaking, then this will be highly temperature dependent i.e. leakage increases as the oil viscosity reduces with temperature.

Thanks again @RRPhil. Looks like there’s some testing to do!

When everyone says you need a diagnostic tool to tell you exactly what’s wrong with your car, you think an error code is the key to resolving all your problems. But clearly not in this case!

I will post the solution when I find it. But for now I’m going to put up with the minor inconvenience of an occasional re-start. Des

2005 (2006 MY) L322 4.2sc Java Black, 2010 facelift conversion
1965 Lenham Lemans GT 1310 , Gulf Racing blue, FIA spec and road legal
2018 F56 Mini JCW, Thunder Grey/Black, Mulgari St2 tuned, FMIC, short shifter and Eibach springs

As a reminder, this relates to a problem I was experiencing with my 6HP26 gearbox.

A fluid change at 110k miles introduced a problem that others have also reported online but none of the posts I've seen included a solution. So here it is.

The problem only occurred after at least half an hour of driving and when changing from 3rd to 4th gear. The revs would climb up to ~2k but the gear change to 4th wouldn't happen and then 'bong' - Transmission Fault would appear on the dash. Switching the ignition off and back on again would resolve the issue and sometimes, it wouldn't happen again for the rest of the journey. There were no other symptoms which meant I could live with it, at least in the short term.

As it was coming up to a year and ~10k miles covered in my ownership, I booked the car in with Jason at Pegasus Garage in Kent for its annual service and to fit the gearbox refurb kit I bought recently from a fellow member on here. It included a Zip Kit, new solenoids, pan, fluid etc.

I picked the car up on Saturday and 200 miles later I'm delighted to confirm that the gearbox problem is solved. It may not have required all those parts to be replaced but I'd rather do more and fix it than do less and have to keep coming back to it.

A big thank you to Jason and his team as well. I don't think there is anything they don't know about Range Rovers.

Click image to enlarge

Thanks for posting your fix. Well done glad it's all sorted.

Appreciate it, thanks. It was a gamble and it paid off. Des

2005 (2006 MY) L322 4.2sc Java Black, 2010 facelift conversion
1965 Lenham Lemans GT 1310 , Gulf Racing blue, FIA spec and road legal
2018 F56 Mini JCW, Thunder Grey/Black, Mulgari St2 tuned, FMIC, short shifter and Eibach springs