I’ve been trying to diagnose what I thought was a hesitation from the engine on my 5.0 L322, however the more I’m looking at it I cannot find anything wrong with the engine. It’s logging zero misfires of any kind and there’s nothing jumping out that would be causing any problems.

I drove the car home from London the night I collected it and didn’t notice anything until the last mile up the lane to the house on the up hill bit where the car is under load. I then felt what I thought was a hesitation and put it down to the timing being out slightly due to it needing the timing chains done.

However, since doing the timing chains the engine is silky smooth and is registering zero misfires or anything that could explain these symptoms.

The car is on 114,800 miles, the gearbox oil was replaced at 71k miles in 2015 so doing another oil change is next on my list of priorities. Especially since I’ve read about gearboxes juddering as I’m now wondering if this could possibly be my issue. I’m wondering about the bridge seal and the 4 round dowels that live above the valve block, the electrical sleeve and possibly the solenoids if anybody thinks it might be worth doing them.

I tried with my IID tool to monitor what the solenoids in the gearbox were doing but my IID tool just shows N/A when trying to read the status. I’ve sent Patrick at GAP an email in the hope he has an update available for it.

Here are some screenshots showing engine rpm v turbine speed in the gearbox at various points.

Cruise control on at 65mph. The turbine speed is a straight line whereas the engine appears to be hunting by approx 200rpm. This is visible on the rpm dial. The wiggle in the turbine speed was the adaptive cruise control detecting another car.

I think the EDS2 solenoid current would be useful as an additional measurement (albeit at the cost of a reduction in sampling frequency) so that we can see what the torque converter lock-up clutch is being told to do (i.e. off, controlled slip or locked solid)

Phil

Thanks Phil,

I’d seen you mention this solenoid in one of your previous posts.

The IID tool only lists solenoids 1 through 6 and doesn’t have anything named along the lines of the EDS solenoid. All 6 of them also only show N/A when trying to log any data from them.

I’ve emailed GAP in the hope they might be able to assist.

Failing that, I’ve got a copy of SDD on an old laptop somewhere, with a bit of luck, that might be able to help get the readings needed.

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory 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

At road speeds such as 65mph & 80mph you’d clearly expect the lock-up clutch to be fully engaged (i.e. locked solid) and therefore the engine and turbine speeds would be identical. As they aren’t, this would appear to be a LUC issue.

The engine flare when going off the throttle and then tipping back in again could simply be the LUC disengaging for overrun and then re-applying again for drive. Again, the solenoid 2 current would tell us if this was the case. I hope GAP can shed some light on the missing live solenoid data.

Phil

Thanks Phil, your input is massively appreciated. I’ve been chasing my tail thinking this was an engine fault after I’d done the timing chains and not getting anywhere with it.

Is there a particular drive style whilst mapping the rpm, turbine speed and solenoid 2 activity that would be beneficial? Would a motorway run on cruise control like the other graphs work or would a drive as it goes up through all the gears be better?

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory 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

Gentle acceleration up through the gears would show the point at which the LUC is applied and then the transition from controlled slip mode to fully-engaged.

The example below is from a 6HP26 where you can see the controlled slip mode activated in 3rd gear and then full lock-up at the 4-5 upshift point. The LUC is fully locked in 5th and 6th gears.

My IID tool isn’t doing anything with the solenoids unfortunately despite changing the firmware as suggested by Patrick

I dug out my old SDD laptop and have found the engine speed and turbine speed but cannot find a thing about the solenoids or torque converter lockup.

Loads of stuff about clutch fill times though.

This is the whole list is what can be monitored from the Transmission ECU using SDD.

That’s very disappointing. So it isn’t looking like we’ll get to the solution through diagnostics, and replacing the torque converter is obviously a big job. I just wondered if it might be worth replacing EDS2 first, on the off-chance that it’s a solenoid fault causing the issue, before resorting to major surgery?



I have a couple of used solenoids that I can send you to try, free of charge. A new bridge seal & the 4 jump tubes cost around £40, and you could reuse the fluid, so it shouldn’t be an expensive thing to try.

Alternatively, you should be able to source a new solenoid through JPAT or Sussex Autos (ZF part number 0501 214 958).

Do you think this might be worth a shot?

Phil

I was beginning to wonder the same thing if I’m honest.

Do you know if the solenoids would be the same as the ones in a 6HP26?

I replaced the full set in the gearbox on my 2007 4.2SC when the gear change was a bit jerky. After about 2-3000 miles the car lost drive and I mistakenly diagnosed it as the gearbox when it was in fact the transfer box so I’ve got a virtually new full set of solenoids here.

According to the history the oil in the gearbox was changed about 40k ago in 2015 so I’m thinking it might not be a bad idea to service it anyway. I bought a 20 litre drum from Smith and Allen when I did the gearbox swap on the last car so I might even have enough fresh oil anyway. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory 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

The yellow cap & blue cap solenoids from the 6HP26 are the same parts used for the 6HP28, but the 6HP26 didn’t use the orange cap solenoids. The function of the orange cap solenoids is the same as the yellow cap (i.e. increasing pressure with increasing current), but the inlet and outlet ports are reversed, so they aren’t interchangeable.


6HP26 solenoids



6HP28 solenoids




Phil

Thanks Phil, I didn’t remember seeing the orange cap ones which now makes sense!

I guess until I know for sure what’s going on inside the box there’s no point spending a lot on solenoids, etc. as it could still be the torque converter itself like you said above.

Mackie’s in Glasgow have just quoted me £207.15 + VAT per solenoid using the part number you gave.

Sussex Auto’s aren’t quoting much more then the price of 1 solenoid from Mackies for the entire kit.

Until I know for sure what’s going on though, it would be nice to keep the cost down so I’d be eternally grateful to be able to take you up on your offer of the used solenoids.

I’ve got around 7 or 8 litres of fluid here to top it back up so I’ll order up the seals today too.

Is it worth changing the blue and yellow solenoids with the nearly new blue and yellow solenoids I have whilst I’ve got the valve block out or is it a case of only change as little as you need to?

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory 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

Although I can see why it would be tempting to change as many of the solenoids as possible while you’re at it, especially if you have much newer ones lying around, I’d be concerned that this may lead to further complications as all the pressure & time adaptions would initially change and the controller would be trying to adjust the shift times for all the clutches at once. If you possibly can, I would just try to stick with the single solenoid change (EDS2) so that we can immediately see if it has any effect.

If you want to send me a PM with your address, I’ll get the solenoids sent off to you. I have two (used) orange cap solenoids, so I’ll send you both and you can decide which one to try.

Phil

Hi guys,

Not much help here but I would add, I have used Mackies for my 4.4TDV8 transmission servicing as well as oil flushes to diffs and transfer box. The service and knowledge from David and the team is absolutely faultless. I live in Scotland and they really do have a terrific reputation, not only retail but trade as well. I wish I could help you more. Thanks

Thanks Phil, PM incoming

That makes perfect sense with not changing all of the solenoids. It makes perfect sense to change one thing at a time rather then potentially introducing faults.

It’s odd that this car drove perfectly when I collected it in London. I drove it 400 miles home to Glasgow and then on the last 250yds I noticed a tiny amount of judder.

It was parked up for 3 months whilst I changed the timing chains and rebuilt the Supercharger and the symptoms have slowly worsened.

On the drive home it was locked up properly in 6th, now it’s not locking up at all so hopefully it’s just this solenoid. Is there anything I can do to choose which or the two you’re sending is the better one to fit or is it just pick one and see what happens?

I’ve worked on a friends car that was in at Mackies for a gearbox rebuild many moons ago. They did a major service on it whilst the car was there inc plugs, timing belt, etc. When I serviced it for him I found mismatched plugs and bolts missing so I don’t share your experiences with them unfortunately.

The prices they are quoting are mental as well… all 4 of the rubber dowel seals that live above the valve block are under 3 quid inc VAT from Land Rover, they were all over 10 quid + VAT from Mackies. For a full set of gearbox solenoids for my car they are quoting £397 + VAT, Sussex Auto’s are quoting £243 + VAT. I like buying locally and supporting small businesses but those prices are way more than I’d be prepared to pay for the privilege.

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory 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