Hi all,
Still far from fit and battling the NHS for answers but got to the point I just decided I have to start living my life and what will be will be.

Anyhoo, that brings me onto the other struggle in my life which is range rovers.
I've got the sunroof drains clear and after weeks with a fan heater blowing under the passenger side carpet it seems to be dry so hopefully I'll get a path cleared to the door and get it outside to see if it stays dry. By the way, there is a huge lump of foam under the passengers feet that weighed about 20kg when it was wet through.

The next thing I want to investigate is the gearbox.
The previous owner said that the box had been reconditioned (maybe meant serviced, who knows) and since then it doesn't select 5th or 6th in automatic.
Drives fine up to 4th then you have to flip it to manual to get to 6th. Once in 6th you can put it back in auto and it stays there until you slow down. Slowing down it changes fine.
Anyone ever had anything like this?
Also, is @Bemble still around? He's not far from me but I sent him a message on here and no reply as yet. If anyone knows any other way I can get hold of him I would appreciate it.

Finally, I have to swap out the head unit as the one in there is toast. Anyone know how big a job it is?

I wonder if this is the early signs of a worn rear stator bush. This is a very common issue with the 6HP26 and this bush acts as a seal for the E-clutch hydraulic circuit. When it wears & subsequently leaks, the pressure on the E-clutch drops and the clutch can slip. The transmission control system detects this and tries for a higher gear. The E-clutch is used in 4th, 5th & 6th gears so the control system tries for 4th, detects slip, tries for 5th, detects slip, tries for 6th, detects slip & goes back to 3rd gear.

I appreciate that this doesn’t exactly match your symptoms at the moment, but possibly the wear isn’t serious enough (yet) to affect all three higher gears. The usual check for a worn bush is to remove the Mechatronic unit and apply air pressure to the E-clutch feed port to see whether the air meets a dead end or if it can be heard rushing in. Because the leakage will be less when the viscosity of the fluid is higher, the problem may not exist when the transmission is cold but then start once the fluid has warmed up.







Phil

Bemble said:

I wonder if this is the early signs of a worn rear stator bush. This is a very common issue with the 6HP26 and this bush acts as a seal for the E-clutch hydraulic circuit. When it wears & subsequently leaks, the pressure on the E-clutch drops and the clutch can slip. The transmission control system detects this and tries for a higher gear. The E-clutch is used in 4th, 5th & 6th gears so the control system tries for 4th, detects slip, tries for 5th, detects slip, tries for 6th, detects slip & goes back to 3rd gear.

I appreciate that this doesn’t exactly match your symptoms at the moment, but possibly the wear isn’t serious enough (yet) to affect all three higher gears. The usual check for a worn bush is to remove the Mechatronic unit and apply air pressure to the E-clutch feed port to see whether the air meets a dead end or if it can be heard rushing in. Because the leakage will be less when the viscosity of the fluid is higher, the problem may not exist when the transmission is cold but then start once the fluid has warmed up.

Phil

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Thanks Phil for the, as ever, comprehensive reply.
I don't feel it attempting other gears and I think it goes into 4th OK.
The PO said this started after a gearbox "refurb" but I have no idea what the refurb consisted of. I suspect just a fluid change.
As I said, it drives flawlessly in manual mode which is what I found strange.
Do you know if commanded changes are visible in gap iid? I could then see if its attempting to change.
If all else fails, would you be interested in doing a complete last nut and bolt rebuild of the box?

First of all, I hope your health issues get resolved as soon as possible, it is bad enough having to worry about an ailing Range Rover! I am sure you will have already done a load of 'plug in diagnostics', but it really IS worth running more than a few.....initially we thought our 'dreaded' GM 5 speed box (much worse than the 6 speed Z) was toast due to the trans failure kicking in regularly, however after perhaps FIVE full scans and clearances it has been perfect....lots of miles, including towing etc and some hard driving. It is just a thought but surely worth trying.
All the best

nevillen said:

First of all, I hope your health issues get resolved as soon as possible, it is bad enough having to worry about an ailing Range Rover! I am sure you will have already done a load of 'plug in diagnostics', but it really IS worth running more than a few.....initially we thought our 'dreaded' GM 5 speed box (much worse than the 6 speed Z) was toast due to the trans failure kicking in regularly, however after perhaps FIVE full scans and clearances it has been perfect....lots of miles, including towing etc and some hard driving. It is just a thought but surely worth trying.
All the best Yes, I am planning to do that. I also will be running some traces of available live data from the gearbox to see if it gives any clues.

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We'll, the NHS really isn't doing a great deal for me so I just decided that I needed to get on with life and just take what they provide when they provide it. Not ideal but it is what it is.


Yes, I am planning to do that. I also will be running some traces of available live data from the gearbox to see if it gives any clues.
I just need to get organised to get the new tyres fitted and get the head unit swapped then I can insure it and get it back on the road. It's currently only doing short drives around the yard to keep it all moving.

Wazzajnr said:

Do you know if commanded changes are visible in gap iid? I could then see if its attempting to change.

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If you can record some live data, that may certainly help determine what’s going on. The fewer things you measure, the higher the sampling frequency, so I would suggest just engine speed, turbine speed and output speed initially. The detection of clutch slip and subsequent selection of the next gear takes fractions of a second, so we need the best resolution possible.

Wazzajnr said:

If all else fails, would you be interested in doing a complete last nut and bolt rebuild of the box?

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I’m afraid I’m now retired and don’t get my hands dirty anymore. Sorry.

Phil

Bemble said:

If you can record some live data, that may certainly help determine what’s going on. The fewer things you measure, the higher the sampling frequency, so I would suggest just engine speed, turbine speed and output speed initially. The detection of clutch slip and subsequent selection of the next gear takes fractions of a second, so we need the best resolution possible.

I’m afraid I’m now retired and don’t get my hands dirty anymore. Sorry.

Phil

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Retired? That's a major loss to Landy owners, hope you will still be dispensing your knowledge.
Regardless of the above, enjoy your retirement, it's a good time of life

Bemble said:

If you can record some live data, that may certainly help determine what’s going on. The fewer things you measure, the higher the sampling frequency, so I would suggest just engine speed, turbine speed and output speed initially. The detection of clutch slip and subsequent selection of the next gear takes fractions of a second, so we need the best resolution possible.

I’m afraid I’m now retired and don’t get my hands dirty anymore. Sorry.

Phil

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That's a darned shame! Any recommendations around Lancashire for someone who knows what they're doing with these?
Enjoy your retirement, I'm not in the least bit jealous!

Depends on where in Lancashire, but Tameside transmissions in Droylsden/ Tameside- Ashton under lyne area, about 15mins from the M60 are who iv used a number of times for service or repair, only do gearboxes and do know there stuff.

Just noticed your Chorley area? So not far from them really.

I guess Automatic Transmissions Preston Ltd on Emmanuel Street is the best known in our immediate area. They've been going for donkey's years

Phil

Bemble said:

I guess Automatic Transmissions Preston Ltd on Emmanuel Street is the best known in our immediate area. They've been going for donkey's years

Phil

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Crumbs, are they still going? I took a mk2 granada to them with a broken sprag clutch in about 1988.
I didn't bother fixing it in the end, just drove it on the selector in second and third.
I'll do some diagnostics when I get it back on the road then decide what to do. Thanks for all your advice.