Suddenly shift into neutral when drving?

[oldgun]

DCT tranmission, I believe it's the wet clutch, done 188K KM.

it's driving very well when it's cold, but after 20 minutes, it suddenly shifts into neutral, loose gas then it shift drive mode.

Changed fluid, penrite DCT, flushed 2 times, waiting for the filter.

whats the issues? any fix?

thank you heaps

[AlanM]

It could help if you performed a clutch learn using Forscan while the transmission is fully warmed up.

If you don't have Forscan, it's free to download. Put it on a laptop then all you need is an OBD/USB adapter, good ones can be had for about $50 on ebay.

Did you make sure to follow the correct procedure when changing the transmission oil? If not the front compartment could be low on oil, which would result in loss of hydraulic pressure on the clutch and shift actuators. There's videos on YouTube on how to do it.

[oldgun]

Originally Posted by AlanM

It could help if you performed a clutch learn using Forscan while the transmission is fully warmed up.

If you don't have Forscan, it's free to download. Put it on a laptop then all you need is an OBD/USB adapter, good ones can be had for about $50 on ebay.

Did you make sure to follow the correct procedure when changing the transmission oil? If not the front compartment could be low on oil, which would result in loss of hydraulic pressure on the clutch and shift actuators. There's videos on YouTube on how to do it.

Thank you so much mate

I found it drove not smoothly when I got it, then changed fluid according to the YT or manual. then it drives very smotthy, no shuddder or hesitation. then this happens, when I was waiting for redlight on uphill, it shift into neutral, pressed gas again, it drove normally.

[goz007]

Sounds like it's low on oil.

[oldgun]

Originally Posted by goz007

Sounds like it's low on oil.

I have double checked the level, also just fluashed again.

Added 6.5L fluid into the fill hole under the airbox.

It'a not the low fluid.
I hightly doubt it's solenoid, that's why it's playing up when it's hot, normally after driving around for 2 minutes.

It's butterly smooth when it's cold.

Net step is remove the valvle body and clean those solenoids

[goz007]

Get Forscan & get transmission up to running temp(when it's having the issue)u will be able to manually command/test the solenoids to confirm what u are thinking.

[goz007]

How was the transmission behaving before u performed the service? I also believe it's about 7lts for a full fill, try jacking the car up on an angle so the highest point for the trans is it's fill point(so right side on the ground & left side up)

[oldgun]

Originally Posted by goz007

How was the transmission behaving before u performed the service? I also believe it's about 7lts for a full fill, try jacking the car up on an angle so the highest point for the trans is it's fill point(so right side on the ground & left side up)

I bought it not long ago, with jerky trans, so I changed fluid then it became very smooth in every first cold drive 20 min.

I changed the filter which still was the orginal filter, totally clotted, see how it goes with new fluid and filter yesterday.

Unfortunately I don't have specific scan tool, only OBD dangle which is not up for the task.

thank you all for the kind replies

[oldgun]

Originally Posted by goz007

How was the transmission behaving before u performed the service? I also believe it's about 7lts for a full fill, try jacking the car up on an angle so the highest point for the trans is it's fill point(so right side on the ground & left side up)

I believe it's 7.3 L dry fill, refill is about 6.5 L, considering the cooler and filter and tubes.

Also should it be level ? what's the issues if I overfill it ? lets say, 7.5L? any probs?

[AlanM]

Originally Posted by oldgun

I believe it's 7.3 L dry fill, refill is about 6.5 L, considering the cooler and filter and tubes.

Also should it be level ? what's the issues if I overfill it ? lets say, 7.5L? any probs?

Just to be sure, did you follow the procedure of filling until it runs out the level drain, then replacing plugs, running the engine and shifting through all the gears for a few minutes, switching off, removing plugs, and most important waiting for the oil to stop running out the level drain again before topping up till it overflows again. And you do want the car level when you do this.

The problem is, if you don't follow the procedure properly and just put 7 1/2 litres in, you'll end up with the rear section of the transmission overfilled, but the front, where the oil pump and valve body are will be underfilled.

[oldgun]

Originally Posted by AlanM

Just to be sure, did you follow the procedure of filling until it runs out the level drain, then replacing plugs, running the engine and shifting through all the gears for a few minutes, switching off, removing plugs, and most important waiting for the oil to stop running out the level drain again before topping up till it overflows again. And you do want the car level when you do this.

The problem is, if you don't follow the procedure properly and just put 7 1/2 litres in, you'll end up with the rear section of the transmission overfilled, but the front, where the oil pump and valve body are will be underfilled.

Yes, I did exactly what manual says. even used leveler to make it's level.

take what drained off about 2-300ml. total fill about 7L.

[goz007]

No over filling is not a good idea, Jack up so fill point is the high point(so one wheel on the ground the other lifted), & fill like that, as suggested then run through all gears several times, recheck level, lower car & take for a short run(enough to get to running temp), making sure u run it in all gear & manual mode-important, bring back put on a level surface & recheck oil level(level check should be done on flat level surface@operating temp) the other investment u should make is the dongle for FORSCAN(LINKER LS or OBDLINK EX are the two best & recommend by FORSCAN) Then it gives u the opportunity to reset the TCMs learning parameters which will reset shift points & pressures(when resetting there is a learning process to correctly relearn shift & shift pressures-best done at a quiet time & a place with not much traffic to start off) basically start off with limited throttle & gradually run it through the gears until top gear is achieved then let it coast to a stop without using brakes if u can, then repeat this using different throttle inputs, until eventually a few free spirited runs (I like to use an on ramp of a freeway/motorway).....but in the end the condition that u described your transmission in when u serviced it it could be also the the clutchs also have significant wear & have done there day, as Ford also recommends 60k service intervals for these transmission....

[goz007]

https://forscan.org/download.html

[oldgun]

Originally Posted by goz007

No over filling is not a good idea, Jack up so fill point is the high point(so one wheel on the ground the other lifted), & fill like that, as suggested then run through all gears several times, recheck level, lower car & take for a short run(enough to get to running temp), making sure u run it in all gear & manual mode-important, bring back put on a level surface & recheck oil level(level check should be done on flat level surface@operating temp) the other investment u should make is the dongle for FORSCAN(LINKER LS or OBDLINK EX are the two best & recommend by FORSCAN) Then it gives u the opportunity to reset the TCMs learning parameters which will reset shift points & pressures(when resetting there is a learning process to correctly relearn shift & shift pressures-best done at a quiet time & a place with not much traffic to start off) basically start off with limited throttle & gradually run it through the gears until top gear is achieved then let it coast to a stop without using brakes if u can, then repeat this using different throttle inputs, until eventually a few free spirited runs (I like to use an on ramp of a freeway/motorway).....but in the end the condition that u described your transmission in when u serviced it it could be also the the clutchs also have significant wear & have done there day, as Ford also recommends 60k service intervals for these transmission....

Thank you so much for you reply.

It drives very good after I replace filter and refilled fluid, check the level again. so far so good.

Mechanic wise I think it's in good working condition, there's no slipping gears or other issues.

[oldgun]

Originally Posted by goz007

https://forscan.org/download.html

good man

thank u again

[oldgun]

Took it for a long drive about 90 minutes, it has been doing well untill on the way home, shifted into neutral again on uphill, RPM to 5K, then it's back to normal.

It happened so often on uphill.

otherwise, no issues whatever.

[oldgun]

Removed the TCM and cleaned seninods, changed fluid again.

REmained same prob.

Then I removed cooler and flushed coolant, looks like it never been changed before.also oil cooler is half blocked, removed filter housing and two pipes, cleaned and blowed dry.

Then I can feel the oil flowing inside the pipes.

Took it for 40 minutes spin, no prob whatever.

It shifts gears very quickly.

It's the oil cooler blocked!!!

[oldgun]

some photos

[oldgun]

Also, I have found it's not that hard to replace the internal filter, use a 90 degree adapter to make job so easy.

[AlanM]

Originally Posted by oldgun

Removed the TCM and cleaned seninods, changed fluid again.

REmained same prob.

Then I removed cooler and flushed coolant, looks like it never been changed before.also oil cooler is half blocked, removed filter housing and two pipes, cleaned and blowed dry.

Then I can feel the oil flowing inside the pipes.

Took it for 40 minutes spin, no prob whatever.

It shifts gears very quickly.

It's the oil cooler blocked!!!

Good job fixing it! Did you find what was blocking the cooler?

[gh172]

My Volkswagen Golf used to slip into neutral. For my car , I had to get a new Mechatronic unit.

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