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Discussion Starter #42
An update!

Left the battery disconnected overnight, went out today to do some data logging on it so I could check the reference values. However, before I could data log, I needed the Cobb to connect to the TCM ECU. Because I uninstalled it to rule it out as a problem, I had to reflash the TCM. Once that was complete, I could begin the data logging.

As I began the data logging, shifted to drive, moved a bit, shifted to reverse, moved a bit... and so on. Suddenly works fine!!!!! I don't know why it's suddenly sprung to life again. I drove it up the road, then a bit further and a bit further, manual through the gears and auto in normal and R modes, reverse, etc.... all good.

I'm now wondering if this was a software issue all along and/or the battery reset did something. Or of course it could be pure fluke and the problem might come back.🤷‍♂️ I'm not quite happy though, if it had failed, it might have been better as I'll always have a worry in the back of my mind about the issue coming back.

My next step is to carry out the gearbox service on the weekend so at that point, I'll drop the ACM module and have a look at the general condition whilst replacing the filters, cleaning the sump and refilling with new oil.

For the moment, thanks to everyone who's been following the thread and posted messages - even if it's just to show support, it's really appreciated :)
 

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Glad to see your up and running again. I think a clutch relearn is in order if it's been slipping, that's if it does'nt do it when you put the map on.
 

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Discussion Starter #44
Glad to see your up and running again. I think a clutch relearn is in order if it's been slipping, that's if it does'nt do it when you put the map on.
I should have mentioned I did that as soon as it was up to operating temperature. All seems good. I'll report back once I've done the gearbox service and looked over the ACM (y)
 

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Glad its sorted. It could well be a battery and ECU issue. I once hit a bumpy road surface (series of rough potholes) and the car went in to limp mode and flashed up TCM/ECU visit dealer etc message. Car on Cobb tune. Cleared the codes and car went back to original map. Did it again two days later. Turned out to be a slightly loose battery connection. Sorted that out and has not done it again, 2 years and counting....spoke to Cobb at the time and it turns out that if the battery drops below a certain voltage it can cause the software to go into a safe mode as the ECU is trying to "work" outside the parameters it is expecting. Might have done something similar in your case? Think it was Barry P asked about trans oil pressure in an earlier post - if that is showing as OK then I wouldn't think it's a piston seal failure and if its selecting gear OK looks like the "mechanics" are all good. Both then suggest electrical/software fault to my (admittedly untrained) eye
 

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Discussion Starter #47
Another update :)

Dropped the oil, sump, filters and ACM module last night - let me just say; it's so much easier than I thought it would be!

Here are some pictures, first, the oil draining:
266578


Next, the transmission sump being dropped. Note the angle. If you're dropping the sump and it's a flat pan, it's always best to lower the bolts and remove them in order so it tilts towards the drain hole - that's how you save yourself being covered in oil!!!
266579


Once the sump is removed, the bottom of the box is exposed.
266583


The large dark grey square with a diamond shape mesh is a filter. It's not fixed in any way other than pushed in, so it's a case of grabbing it and pulling it down. Note, when its pulled out, a load of oil will follow!

Then you see the ACM module. This is the part that does the gear selection. NOTE there are little holes on here which keep the pistons from moving. I realised this once I removed it... it's important to put something in these holes (I used copper wire) to keep the pistons from rotating otherwise the positions of the pistons will not be detected correctly by the sensors! It also makes it easier to like the pistons up with the shifter forks:
266582


This is how it looks when it's removed. The pistons which select the gears are on the left, the solenoids which control the pistons on the right under and around the black cover).
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You may see in the picture above, there were some metal filings on the pistons, close to the piston position sensors (the grey/blac coloured blocks). I used a stronger magnet to remove these away from the pistons/sensors.

I began removing the solenoids and inspecting them. I used some carb cleaner to clean them (NOTE: NOT BRAKE CLEANER, this might damage them) and shook them up and down to ensure they moved freely.
266584

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You'll note there are different types of solenoid. The one above is the Clutch A/B solenoid. There are 2 of them. The one below is the piston control solenoid (the ones i've labeled solenoids 1 to 4 on the diagram I posted up a few posts back.

NOTE: when removing the piston control solenoid, be very careful. Underneath them lay a spring, a ball bearing and a small casing.
266586


I removed all of these components, cleaned everything and checked the ports for any debris, cleaned the ports and gave them a little carb cleaner too:
266587
 

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Discussion Starter #48 (Edited)
I've got a video of the solenoid and how it sounds when it's free. I'm not sure how to post it other than adding a Youtube link!


This picture is more just for reference. It essentially shows that this is a manual gearbox with automation. The ACM module selects the gear by moving the pistons which in turn engage the forks that they mate to. If it didn't have the ACM module, you would have had a gear lever in the car, and a clutch pedal (hope that helps explain the role of the ACM module).
266588


I removed the old paper secondary filter which is also up in the box and replaced it with a stainless one. Some say you should keep the paper one which filters a finer level of particulate than the metal one. I tend to agree but I think there's a balance between starvation caused by excellent filtration, and good oil flow with decent filtration.

266589


266590


I cleaned the sump and the magnet thoroughly, there was some sludge on the magnet but nothing extraordinary I don't think? Although this is the first GR6 box I've worked on:
266591



I dont have more pictures as it was getting late! But I then replaced the large square filter with a new one and put it all back together.

Findings and conclusion so far:
When I dropped the transmission oil, it absolutely reaked of burnt clutch.. like a learner driver has been riding the clutch in traffic up a hill on a hot day kind of smell. The oil was also black and very goopy/thick. I suspect this was very much overdue a transmission service.

After putting it all back together, refilling with oil and following the heat up, changing of gears cycles and adjusting the oil level, I can tell it feels different in selecting gear. It didn't seem to 'clunk' into gear and didn't seem to shudder/judder at low speed movement.

That said, I haven't driven it yet (as I said, it was late and I live in the countryside so it's too dark to break down LOL). I'll be doing the rear diff service today, then taking it for a drive. Do a clutch relearn then drive again. let's see how it goes.

Look out for an update!
 

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I've got a video of the solenoid and how it sounds when it's free. I'm not sure how to post it other than adding a Youtube link!


This picture is more just for reference. It essentially shows that this is a manual gearbox with automation. The ACM module selects the gear by moving the pistons which in turn engage the forks that they mate to. If it didn't have the ACM module, you would have had a gear lever in the car, and a clutch pedal (hope that helps explain the role of the ACM module).
View attachment 266588

I removed the old paper secondary filter which is also up in the box and replaced it with a stainless one. Some say you should keep the paper one which filters a finer level of particulate than the metal one. I tend to agree but I think there's a balance between starvation caused by excellent filtration, and good oil flow with decent filtration.

View attachment 266589

View attachment 266590

I cleaned the sump and the magnet thoroughly, there was some sludge on the magnet but nothing extraordinary I don't think? Although this is the first GR6 box I've worked on:
View attachment 266591


I dont have more pictures as it was getting late! But I then replaced the large square filter with a new one and put it all back together.

Findings and conclusion so far:
When I dropped the transmission oil, it absolutely reaked of burnt clutch.. like a learner driver has been riding the clutch in traffic up a hill on a hot day kind of smell. The oil was also black and very goopy/thick. I suspect this was very much overdue a transmission service.

After putting it all back together, refilling with oil and following the heat up, changing of gears cycles and adjusting the oil level, I can tell it feels different in selecting gear. It didn't seem to 'clunk' into gear and didn't seem to shudder/judder at low speed movement.

That said, I haven't driven it yet (as I said, it was late and I live in the countryside so it's too dark to break down LOL). I'll be doing the rear diff service today, then taking it for a drive. Do a clutch relearn then drive again. let's see how it goes.

Look out for an update!
Congrats - glad to hear you've managed to sort the problem.
 

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Discussion Starter #51
You should have cleaned the body out as there’s a lot of small filters in there.

other than that, great job.
Darn! Didn't realise there were more filters if I split the module. I'll do that on the next service. I've set a reminder for 3000 miles (y)
 

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Discussion Starter #52
Took the car out tonight, drove it extremely slowly and heated the box up. Got it to operating temperature, then did a clutch relearn. After that, I took it for a really good hammering.

All fine now! Thanks so much to everyone following, posting and contributing :)
 

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Great news mate.
As they say switch it off and back on again = Fixed :ROFLMAO:
 

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You’ve made that look much easier than it probably is! Nice work.
 
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