Auto box question

[swiveleyedgit]

Hi all, just thought I'd update this thread a little after giving the car it's first oil change. I'm planning to give the car another oil change over the Xmas break but wanted to ask about another small problem that I've noticed. Every now and again the box will stick in gear until the engine is restarted, normally third gear, it's happened twice in the last three months. In between times the changes are nice and smooth and, having recently given the car an Italian tune up on my private test track, I've noticed there are no untoward noises coming from the transmission even at high speeds, it's nice and quiet.
Now my question is would the sticking be an electro valve problem and would it be beneficial to change both of them at the same time as changing the oil? Also, if it would be, is a new gasket required when doing so? As usual any advice gladly received.

[swiveleyedgit]

Just thought I'd bump this, I'm going to change the electro valves this week, will I need to fit a new seal to the cover or will the original one be ok?

[wheeler]

I've never had a problem re using the old seal. Do you know its highly advisable to make sure the autobox ECU has the latest software version when fitting new electrovalves ? Also the injection ECU & autobox ECU's should also be updated together.

[lexi]

What I would like to know is who designed and built the AL4 box?

[Stickyfinger]

What I would like to know is who designed and built the AL4 box?

[swiveleyedgit]

What I would like to know is who designed and built the AL4 box?

Oh heck, not that pair... I've managed to remove the valve block today, the electro valves are the newer type,, black connectors, which I recall reading somewhere were fitted to some of the later mk1 cars. Hopefully this means the ecu will already have the correct software installed. The outer seal is pretty rough around the bottom edge so I've ordered a new one anyway. Will clean everything up tomorrow as low light stopped play today.

[CitroJim]

What I would like to know is who designed and built the AL4 box?

Siemens...

Is the correct answer...

[swiveleyedgit]

I've spent today replacing the valves and cleaning the valve block and it's now bolted back up to the box. Now comes the tricky bit, putting the 'roller blade' back. I have actually screwed it back on in exactly the same position as when it was removed, the selector mechanism is in the park position and hasn't been moved during the time it's been dismantled, but is that close enough? or do I have to follow the procedure in the rebuild manual, which involves setting the selector in position 2, wherever that is, and using a special bolt to temporarily fix it. i haven't put the cover back on yet, I'm going get the missus to sit in the car and run the gear lever through all the positions while I have a look. (in the morning though, she'll get grumpy if I wake her up at this time of night )

[swiveleyedgit]

Today's update, put everything back together, started it up and let it warm through. The car is on axle stands under the front with the wheels off so I've run it through the gears a few times. Neutral is a bit hit and miss so there is a bit of adjustment required. It will find drive, reverse and park ok, I've realised now that I could have tried this by just sitting in the car with the ignition on, I can see on the display whether it's going into gear or not. Still, another quick oil change won't do it any harm

Update number 2, Madam has finally got in from work so she kindly held the gear lever fully back in drive while I adjusted the internal lever. Now it goes from one gear to the next as it should, with the display confirming it. Something else I can hear now is a faint buzz from a solenoid as you go from one gear position to the next. It lasts for maybe half a second and then stops. Is that normal?, it doesn't do it with every movement of the lever, just now and again, a bit random. This is without the engine running by the way, or any oil in the box.

[lexi]

Siemens...

Is the correct answer...

Do you mean with massive help from another German company and paying license? They designed that from scratch? Without infringing design copyrights or patents?
Any more info Jim?

[CitroJim]

Siemens...

Is the correct answer...

Do you mean with massive help from another German company and paying license? They designed that from scratch? Without infringing design copyrights or patents?
Any more info Jim?

The AL4 is only superficially similar to the ZF HP20 and similar so I don't think there was any collaboration Lexi. One significant difference is the use of band brakes in the AL4, the ZF 'boxes use multi - plate clutches as brakes... Also the electronic aspects are very different.

[lexi]

Interesting Jim. I know Siemens are like mahoosive. You know Honda could not build an epicyclic box way back when. The patents were all taken by the big players. They had to design their own from scratch without epicyclic gears.(Hondamatic) Toyota managed to get in on act by buying into Borg Warner( now Aisin Warner) and all their technology.
So did Siemens only build one box for small autos, then no more? They may do Loco boxes mind.

[Mandrake]

Bob did you check and update the ECU firmware with a Lexia as wheeler recommended ?

With the new type electrovalves it's absolutely mandatory that the ECU firmware is up to date or it will not function correctly. I wouldn't drive it anywhere until you have confirmed this is up to date in case it causes mechanical damage to the box, as malfunctioning electrovalves could potentially cause a clutch/brake in the box to burn out by activating the wrong combination of clutches and brakes at the same time or failing to regulate the rail pressure correctly.

[swiveleyedgit]

The old electro valves are the black type Simon, according to the posts I've found by doing a search the ecu should already be running the later software, I have a Lexia so I can update it if needed, I'm not sure if this is already loaded on my version though? Can the update be downloaded from somewhere? I have run the engine with the wheels off (the car is on axle stands) and gone through the gears, the hubs turn in the right direction depending on what gear it's in so it seems to be working OK.

[swiveleyedgit]

Have just found this which gives some details about the updating process.

[img] The basic guts of an auto haven't changed much for years. The big differences are working tolerances, and how shifts are actuated (electronically, rather than purely hydro-mechanical). Often referred to in AL4 tales of woe, are "the solenoids". There are in fact a good deal of solenoids or electrovalves in the transmission, but the two problem ones are atop the valve body ("hydraulic block" in Franglais) - this is all behind the black pressed metal cover on the transmission front.

Some years ago, the top two solenoids were recognised as a weakness, and revised. These are driven by a pulsed current to avoid permanently magnetising or overheating. Old solenoids were pulsed at 50 Hz, while the newer type are pulsed at 100Hz. Solenoid failure here, causes the default into "limp home" mode. When these are changed, the transmission ECU is supposed to be updated with a computer download. The update can be done without changing solenoids - old ones will operate on a 100Hz pulse, but newer units won't function satisfactorily on 50Hz.[/img]