Auto-adaptive Gearbox

Hi ZF 4HP20 enthousiasts:

Thought I'd inform you about the file, apparently posted by someone in Finland (but English language):
Citroen Training Manual Automatic Transmission XM & Xantia:

http://sitruuna.unk.fi/pub/korjausoppaat/X...0_Xantia_XM.pdf

I've made an appointment with my dealer to do a fluid replacement at 41,000 km.

Check out recent postings on the subject here:

http://autos.groups.yahoo.com/group/XM-L/

Jan

This post has been edited by Jan-hendrik on September 08, 2007 06:47 am

I have finally found the time to replace the gearbox fluid "completely". You may remember I said I was going to try this in an earlier post. It worked a treat and I got rid of all the old fluid which had done 105k miles and replaced it with new. None of this only draining 2 litres out.

There is a pipe that runs from just below the cooler down the back of the gearbox and across to end of the gearbox. It returns the gearbox fluid to the sump. I got a friend who was going to France to get me one of these in France. Citroen parts here said they would have to order it and they wouldn't get one till sufficient numbers were required in the UK - that will be never then. I cut this pipe in two and attached hoses. One end is formed to a flange about 10mm from the end and sealed using an O ring. The pipe is pushed into the gearbox just below the cooler unit and held in place by a steel plate bolted to the gearbox. The other end is a typical Olive style fitting. By removing the passanger side front wheel and a small removable section of the under wing plastic protection you can gain access to the end of the gearbox and the pipe. Indeed the Olive end is about half way up the end of the gearbox at the rear and is right behind this plastic section. Having removed the existing pipe I attached both ends of my cut pipe and hoses. I then drained the gearbox sump and filled it back up with clean fluid. Interestingly four litres came out and not two as the books say, perhaps it's two for the 4HP18 and four for the 4HP20. The 4HP20 has the drain plug on the bottom whereas the 4HP18 has it at the back and up the side. You only get (I am guessing about the volume) the other two litres out the 4HP18 when you take of the plate covering the filter. Citroen list a filter for the 4HP20 but there is no plate for access like the 4HP18 which is a shame. I filled the box back up by using an oil extraction pump and filling it up through the level hole next to where the drivers side driveshaft enters the diff part of the box. Made life easy. I then started the engine and the gearbox pumped the contents of the torque convertor, oil passage ways, pump etc out the hose. I stopped the engine as soon as around 3 litres had come out and thus avoiding emptying the sump and running the gearbox dry. I filled the sump up again and started the engine.... I repeated this till I had clean oil coming out the gearbox. I then put the old pipe back on and filled the box.
For anyone else who wishes to do this I give the following advice.
I used approximately 12 litres of gearbox oil. It's not cheap but if it keeps the gearbox from dying then it is money well spent.
Now I know which one of the pipe to gearbox connection points the oil is pumped out off I now know you don't need a cut pipe to do this. Slacken the bolt for the plate holding the pipe to the gearbox below the cooler unit slightly. Then remove the bolt and sealing washers from the Olive lower end of the pipe. This will let you move the pipe back from the gearbox at the lower end and you can then put a large hose over that end of the pipe as far as you can and straight down to a basin. Tighten the retaining plate bolt back up. The oil comes out at quite a rate so having only a short length of hose should stop it from coming out the top of the hose too. I would suggest something like a 50 or 60mm hose should do.
I now intend to do normal drain and refills every 18k miles abit like it were a 4HP18.
Sorry no photos.

So far after changing all the garbox fluid I have noticed a distinct increase in accelerator response. The new fluid must be transfering the power through the torque convertor far better.

It seems that the 4HP20 and AL4 gearboxes are one and the same. The only oil that can be used in these gearboxes is Esso LT 71141, problem is that you can only buy this in 20 litre containers and it is VERY expensive. However different car manufacturers offer this oil under their own part numbers. I've seen, but cannot now locate, the Citroen part number but Peugeot sell it in 2 litre cans under part number 9736.22.

However as Max Miller (who he?) used to say: "Now there's a funny thing"! I think I've got to the bottom of this Sealed for Life business. It seems that the 4HP20 and AL4 are fitted with a wear indicator which clocks up gearbox wear as a function of mileage and number of changes. When the wear indicator gets to the pre-programmed number it responds by flashing the Sport and Snow indicators in the panel display, I understand it also switches the gearbox to a backup or get you home mode.

You then have no alternative but to take it to a main dealer where they read the fault code, which tells them whether the oil needs changing. They then proceed accordingly and RESET THE WEAR COUNTER. Without this, you are stuck in the get you home mode.

So even if you do your own oil change, even if you do a complete change like Assich, your wear indicator keeps on incrementing and you will finish up visiting the main dealer to get the thing reset.

With this information in mind, the "sealed for life" policy begins to make sense but it seems to take it out of the hands of DIYers. How many reported failures have there been with the autoadaptive gearbox? Is the advice to change the oil at 50k, 60k, 70k or whatever mileage based only on the experience of failure with the older 4hp18 unit?

After doing an internet search I was horrified by the number of people who are still recommending Dex 3, this is guaranteed death to the later unit.

Derek
PS. Rereading through this complete topic, I found my own post where I gave the Citroen part number for LT71141 - it's the same as the Peugeot, 9736.22

This post has been edited by DerekW on January 14, 2008 07:27 pm

Never heard of this wear indicator thing. Can anyone else confirm this, and/or is there any documentation?

Try www.peugeot206cc.co.uk/repair-206/206/info/gb/t165.htm

Scroll down to draining/refilling/checking of oil.

I know its an AL4 box as fitted to the Pug 206 but as far as I'm aware it's the same as the 4HP20 - with minor differences like the oil level drain plug.

A very neat feature. We can stop being paranoid about premature failure

Hi Jan-Hendrik

Derek is absolutely right about the wear indicator - it's even in the handbook. Although I didn't know about it sending you home in limp home - what a pain. Of course mine didn't need it since the gearbox just simply failed instead

Cheers

Tony

Hi Tony,

Did you ever find out which part(s) failed in your gearbox? Did you have the fault codes read?

I suspect that these failures are usually of the ancilliary bits like oil pumps, valve blocks, speed sensors etc. (Quentin's was the oil pump) and not the gears, friction plates, bearings and all the rotating gubbins that makes up the gearbox itself. Certainly I would suspect these parts as causing faults like rough, noisy or reluctant changes. I think it was Assich who was able to cure his faulty gearbox by changing the speed sensor.

As a number of these parts are external to the gearbox casing, I wonder how often a gearbox change could have been avoided by changing the component?

Derek

This post has been edited by DerekW on January 15, 2008 02:41 pm

Hi!
This wear indicator, you say it's in the handbook. Which handbook is that? I'd like to see that info and then discuss it with my dealer

Hi all,

I thought that this series of posts was worth resurrecting and possibly updating with current info. It's full of good stuff plus a few glitches - mainly from me!

The only correct oil for the 4HP20 is Esso LT71141. Available information suggests that the lock up clutch is the design feature that demands this oil

The AL4 is not the same gearbox as the 4HP20. In my defence the service book for my car refers only to the AL4 and this led me to believe they were the same.

The most common failure seems to be the oil pump.

Oil level checks must be carried out with the engine running because there is an internal sump which is kept filled during operation. If the engine is stopped this sump drains and gives a false level indication.

Now I've located a cheapish source of oil and with my car on 73,500 miles, I'm going to do an oil change. I don't have the confidence to do a complete change like Assich, so as there is no sign of leakage I intend to:

1. Bring the oil up to 60 degrees C, remove the level plug and collect any outflow.

2. Shut down, drain the box retaining all the oil. Add to the oil collected from the outflow and wait until it cools to ambient temperature. Measure the total volume and then put in that quantity of fresh oil through the gearbox breather.

Finally, I think it would be good to hear from the original posters who either suffered a failure or who carried out an oil change. Perhaps they could update us on their later experiences? (I'm thinking particularly of Assich, Tony, and Quentin and Mark if they're still around)

Derek

This post has been edited by DerekW on February 20, 2009 07:40 pm

Hi Derek

We're still driving around in our XM 3years after the box was replaced. That's 20K. It had a fluid change 1000miles after being replaced and has done~15k since. I'm probably going to change the fluid this year.

It seems to be working absolutely fine - as far as I can tell.

Cheers

Tony

Hi Derek

Picked up a full boot load (car not estate) of Pug workshop manuals today. Another ebay moment of madness fortunately the only bidder for most of them. Browsed through a few this evening and found some bits about the 2.5TD that I had not picked up from the Citroen manual. I also came across the manuals for the AL4 autobox as well as the 4HP22, 4HP20 and 4HP14. Quite striking differences in the way the manuals are presented compared to the Citroen ones.

John

Hi Tony, are you going to change the oil yourself or entrust the job to your local Citroen agent? Esso claim the oil is good for 100,000miles but after your experience I understand why you want to do frequent changes. I'll be interested to see the condition of the oil in my box.

What could cause an oil pump to fail? And what would be the failure mode?

Hi John, as an avid collector of technical literature I'm jealous. Anything in there about the VVT V6 or its ECU?

I realise that it takes planning and a lot of nervous anticipation to get stuck into a major job like an autobox removal and strip, but I for one am waiting with bated breath for Citrojim's next posting. I check FCF regularly but there's nothing on there either.

As I've now bought a crane I've no excuse. Time I separated the box from this lump on my garage floor.

Derek

This post has been edited by DerekW on February 21, 2009 05:55 pm

Hi Derek

There are a full set for the 605 and the 406 amongst others. If the engine went into the later 406's then there is a good chance I have got it. I have not looked through most of them yet as there are so many (52) that there was no room at home and they are piled up over in the unit. From the look so far Pug stuff seems to mainly be bound booklets for each of the subject sections so pages do not get lost or moved about like the loose leave Citroen ones. Much easier to see whats there and whats missing.

John