2006 Citroen C4 Auto | AL4 slipping in 1st gear eventually engages with a clunk, when warm

[c4nub]

Huge thanks to Haakon for the parts. Seems like there is an improvement!

And 4th gear works very well so I believe the F1 brake is properly in place.

I noticed however that it has potential to do the same effect as the gear change for first and reverse can delay a bit. After a quick test drive I noticed that the water coolant level has decreased a fair bit. I remember doing a top up with just some demin about 6 months ago.

So I will do a top up of water and investigate. I have a theory that if the heat exchanger seal is no good or if there is a leak somewhere else then the trans oil is heating to above the operating temp and causing a few issues. The engine temp indicator is only 3 bars up which is about halfway and normal.

Will update soon and see what happens.

 

[c4nub]

Update, all seems good. When it warms up, it is hesitant to get off the line like as if there's a lack of fuel supply but it is nowhere near as bad as before. So the new clutch does seem to be making a big difference, but there might be another issue too

 

[Haakon]

Update, all seems good. When it warms up, it is hesitant to get off the line like as if there's a lack of fuel supply but it is nowhere near as bad as before. So the new clutch does seem to be making a big difference, but there might be another issue too

The other things that fail on these are the bronze shaft bushes. Including the oil pump one there are about 7 i think and you will have replaced maybe 4 with this job. But they leak pressure when worn and can eventually stop it...

 

[c4nub]

So I have decided to document my woes and thoughts below in hope that this saves someone from the troubles in future.

It has started happening again once everything is toasty and warmed up. Quite likely that either the bronze shaft bushes, o-rings, seals, EVS3 or EVS4 or are the culprits.

The car drives perfectly in manual mode as 2nd, 3rd and 4th gear have no issues. Taking off at the lights in 2nd or 3rd gear is perfect. Only 1st and reverse struggle when the car is hot.

So only E1 clutch, brake band F3, EVS3 and EVS4 are activated components for first gear.

I have tried a new E1 clutch that was in very good condition and works perfectly fine off the lights in 3rd gear. 2nd gear is working perfectly so band brake F3 should be ok. Both main pressure regulator and converter regulator electrovalves have been replaced. The only items not replaced relevant to 1st gear are EVS3 and EVS4 and bronze shaft bushes, o-rings, seals, etc.

However pug88 the OP changed out EVS3 and EVS4 and still had the exact same issue as me with minimal improvement after the change. So I am a bit stuck now as there is nothing left to try.

To entertain the idea lets look at the transient case that is shifting neutral/park to 1st and shifting 2nd to 1st.

N/Park to 1st - F3 brake band engages and EVS4 closes circuit. Constants are E1 clutch and EVS3 are still activated.

2nd to 1st - E2 clutch disengages as E1 clutch engages. EVS2 open circuits as EVS3 closes. Constants are brake band F3 and EVS4.

There is no constant process in either of these to suggest why it struggles to shift. This is due to the fact that neutral and 2nd share no activated components together. It only slips at the lights as it struggles to shift into 1st. Once it has shifted to 1st it is permanently in 1st with no slippage issues at all. To me this suggest oil pressure problems or electrical issues for inability to shift/attempt to shift to 1st. So the best bet is the bronze shaft bushes, gaskets and o-rings failing. Interestingly when removing the main shaft for a clutch swap twice on both occasions it made a pop noise coming off and oil spilled out as the main shaft was sealed perfectly in there.

Time for an overhaul. It seems something is wrong with oil pressures and the smallest of o-rings or seals could be causing this issue. At least I have my dignity in that I tried all I could with the tools and space available.

Anyone think differently of this analysis?

 

[c4nub]

I should add that the issue is heat dependant so some form of seal is most likely damaged and the problem gets worse when heated. The issue goes away while driving on the freeway as the transmission cools down. It is only the stop start conditions after about 20 minutes where the car bakes and decides it can not shift into 1st from neutral or 2nd.

 

[dimistyle]

The heat exchanger on the back of the AL4 could be blocked or corroded and causing the additional heat as any time these boxes get into stop start traffic they start misbehaving.
Swapping the valve body many also be a solution as they get clogged up and the pistons start sticking. I don't recall if you removed and washed it out.
Does yours have the speed sensor attached this could be triggering fault signals
What error codes are triggered?

 

[c4nub]

Thanks dimistyle! Good thinking and thanks providing all the extra food for thought!

Yeah I have thought about the heat exchanger. Seems very hard to get to and I haven't been able to find it yet. I know what it looks like but am not sure if it is further behind the trans oil pump or something.

When I did the main electrovalves I took the top plate off the valve body and inspected and there was no debris or metal shavings in the veins. I put the plate back on and changed out the main electrovalves as I saw no visible issues. Although it does seem a new valve body could resolve the issue if they are simply sticking. That would also mean just changing solenoids would be a useless endeavour as the new ones would stick too.

With the speed sensor no clue where it would be. This seems like a genuine explanation for the issue I am having though.

No idea about error codes. Have no way of reading them. Last time error codes were read by a mechanic there were only mentions of fuel supply issues and the mechanic diagnosed the wrong problems. Managed to fix it myself as I measured the fuel pump had no voltage.

 

[seasink]

I posted the AL4/DPO repair manual link on the first page of this thread.

 

[c4nub]

Thanks seasink! I am trawling through it now to look at the heat exchanger.

 

[c4nub]

So this page of the repair manual is a gold mine. Huge thanks to seasink! I now know where the speed sensors and heat exchanger are. I should be able to remove the battery mount and replace the heat exchanger provided the gearbox mount is not in the way from above. I still have no means of removing the gearbox and replacing unfortunately. Has anyone swapped out a heat exchanger with the gearbox still attached to the car?

I can access heat exchanger flow electrovalve gearbox input speed sensor and oil pressure sensor very easily and can replace them. Unable to get to the output speed sensor.

Only thing left is changing out the valve body if all of the above fails. After that is gearbox overhaul.

 

[Haakon]

I sort of got roped into a rebuild on one of these at the moment... There was a nice scenic with a slipping trans here in Hobart I was offered to buy, but declined as I have no room for it and didnt have the energy - but was letting him use the low kms Clio trans I had. I had thought he could swap over the bell housing and job done, but alas the main case has a slightly different bolt pattern...

So now both boxes are being stripped and good innards from the clio box transferred to the scenic one. Should have just bought the scenic if i was going to put this much effort in... anyway, hopefully he'll make it worth my while. Sorry, where was I?

Oh yes. If you have been comfortable pulling clutch pack and valve bodies and can clearly read instructions, over hauling it will be easy for you I think. There are a few things you'll need to fork out for like a new converter and have all those bronze bushes pressed into the assorted parts. And disassembling the clutch/pistons on the main assembly is tricky.

But any trans shop even in canberra should be able to do the bush replacement on the parts - i think there is a mob in Mitchell that has worked on these boxes.

Gearbox removal in a driveway/shed with the car on axle stands is not the funnest job in the world, but can be done.

 

[dimistyle]

check you actually have a speed sensor, as ABS sensor or other sensor is used on different models. heat exchanger may need the gearbox mount released to allow had space to remove and refit another. not fun but can be done.

gearbox out on the driveway/roadside is possible our C5 we did this 1/5 a dozen times with subframe off as save time over all

 

[Haakon]

check you actually have a speed sensor, as ABS sensor or other sensor is used on different models. heat exchanger may need the gearbox mount released to allow had space to remove and refit another. not fun but can be done.

gearbox out on the driveway/roadside is possible our C5 we did this 1/5 a dozen times with subframe off as save time over all

It is tempting to leave the subframe in, but I agree its worth the effort to remove.

 

[c4nub]

I sort of got roped into a rebuild on one of these at the moment... There was a nice scenic with a slipping trans here in Hobart I was offered to buy, but declined as I have no room for it and didnt have the energy - but was letting him use the low kms Clio trans I had. I had thought he could swap over the bell housing and job done, but alas the main case has a slightly different bolt pattern...

So now both boxes are being stripped and good innards from the clio box transferred to the scenic one. Should have just bought the scenic if i was going to put this much effort in... anyway, hopefully he'll make it worth my while. Sorry, where was I?

Oh yes. If you have been comfortable pulling clutch pack and valve bodies and can clearly read instructions, over hauling it will be easy for you I think. There are a few things you'll need to fork out for like a new converter and have all those bronze bushes pressed into the assorted parts. And disassembling the clutch/pistons on the main assembly is tricky.

But any trans shop even in canberra should be able to do the bush replacement on the parts - i think there is a mob in Mitchell that has worked on these boxes.

Gearbox removal in a driveway/shed with the car on axle stands is not the funnest job in the world, but can be done.

That sounds like a project came out of nowhere. Do you want the surplus parts that you gave me back? I could not do much with the brake bands and the extra planet carriers.

I managed to remove and attach clutch pistons using two quick grip clamps to a table.

If I buy an engine crane for the trans, I would have to get rid of it once done. I have no space. Also I called wreckers and there are not many AL4s out there. None are nearby. The mitchell mob dont have parts either.

Thanks Haakon!

 

[c4nub]

So I have resorted to just driving in snow mode. No issues at all as it never uses first gear. Brand new clutch and trans oil and main electrovalves so should be ok for the other gears. Anyone know if driving on snow mode would eventually cause damage? More than happy to swap out E2 clutch every 30000km if that is what it takes

 

[Haakon]

That sounds like a project came out of nowhere. Do you want the surplus parts that you gave me back? I could not do much with the brake bands and the extra planet carriers.

I managed to remove and attach clutch pistons using two quick grip clamps to a table.

If I buy an engine crane for the trans, I would have to get rid of it once done. I have no space. Also I called wreckers and there are not many AL4s out there. None are nearby. The mitchell mob dont have parts either.

Thanks Haakon!

You don’t need an engine crane, axle stands, antrolley jack and a friend to hold it steady as you lower it will do it.

I did this to get it back in on the scenic I fixed up and flipped in Canberra earlier this year.

For parts, AliExpress is the go. Or Maneul Automatics in Thomastown in Melbourne sell parts as well - probably the place to get a converter.

 

[dimistyle]

Agree with Haakon, axle stands on high position as you need to be able to slide out the AL4. Aliexpress from China was good quality spares. Otherwise had posted transauto or something similar in Sydney carry all the spares at retail prices

 

[mak407sw]

I should add that the issue is heat dependant so some form of seal is most likely damaged and the problem gets worse when heated. The issue goes away while driving on the freeway as the transmission cools down. It is only the stop start conditions after about 20 minutes where the car bakes and decides it can not shift into 1st from neutral or 2nd.

Hi there, I'm new & sorry to barge in a sudden..
My 407 AL4 is doing the same when temp is high during stop after freeway run at ~120kmh, it will take time to engage D or R, where coolant steady @90 & engine temp slightly higher @~125°C. I've noticed that there is a solenoid control valve controlling al4 fluid going to the heat exchanger (item no. 8). My q, could it be partially block causing the issue? Can we even bypass this .. i.e. drill a hole to the valve to let al4 fluid pass freely all the time thru the exchanger & keeping the fluid to remain steady at 90°C same as the coolant temp? As i live in the tropic Malaysia I don't think this solenoid valve need to regulate/open&close when it is hot already? What do you think?
Appreciate any comments on this to whomever replying.

Thx

 

[dimistyle]

Mak, welcome on board

Have you actually check to see you actually have the control valve, only seen blanking covers and no wiring.
Is commonly blocked by the time you have a 100, 000kms on the odometer, so worth find a suitable replacement, if the 27mm width heat exchanger unit installed go for the 33mm of 40mm if still available, the bolt needs to be replaced as well.

seems to be a bigger issue in stop start traffic.

when was the fluid in the AL4 changed last, a good flush can also minimise this issue

my 5 cents

 

[mak407sw]

Mak, welcome on board

Have you actually check to see you actually have the control valve, only seen blanking covers and no wiring.
Is commonly blocked by the time you have a 100, 000kms on the odometer, so worth find a suitable replacement, if the 27mm width heat exchanger unit installed go for the 33mm of 40mm if still available, the bolt needs to be replaced as well.

seems to be a bigger issue in stop start traffic.

when was the fluid in the AL4 changed last, a good flush can also minimise this issue

my 5 cents

Hi dimistyle,
Thx for the welcome note.

On a 407 al4, the solenoid control valve is stated as item no.4 in the drawing & further search for compatible part number brought me to the Pierburg unit.
I did changed to a new bigger heat exchanger at my regular wshop & with last al4 fluid changed at ~2k km with fluid top up after the job but issue with heat still remain, thus my question...