Auto box level.

[Geoffrey Gould]

Hello all this about getting the level correct when the box is up to temperature. The problem is that if the level is correct when hot and I take it that means to the high (hot?) mark on the stick, then when cold, started, run through the gears and checked the level is Below the low mark.
If I top up the level to the low mark when the box is cold IE. Just started and run through the check procedure then when the box is hot the level is Above the high mark.
So which is best low cold - correct hot or correct cold and over high hot. A bit confused with this one.
Am doing a fluid change soon, Alan you gave a Transmax number that I have somewhat foolishly lost I think it was 'M' is this correct please?
Cheers thank you all.
Geoff.

[AlanS]

Yes Geoff, Transmax M is the stuff we've found to be as good as anything.

To check the level, get engine to running temperature, lift bonnet and keep engine running.
Run up and down the gears a few times with foot on brake pedal as a precaution, and check level.
You'll find the level should be anywhere between the two balls stuck to the dipstick. If it's too full, you will tend to get a type of jolting when it changes gears sometimes. If too low, given the right set of circumstances, it can carry on like a slipping clutch on a manual car (ie) engine speed increasing whilst road speed of the car either holding steady or decreasing.
Overfull can also cause seals to bust.
The reason they have to be tested like this is that the torque converter holds a volume of fluid and depending on several factors including how long it has been stopped and where it's at when it does, can give a variety of readings which is why the protocol I described above needs to be applied.


Alan S

[Geoffrey Gould]

Hello Alan thank you so much for the reply, it explains a lot, Now down to the main reason for changing the fluid and making absolutely sure of the level.
If the throttle is opened quite slowly then the change from 1 to 2 and 2 to 3 is fine smooth and positive but the change from 3 to 4 is not good, the revs rise about 400 rpm then come down to what they should be, it's a very 'soft' change. Once fully engaged it does not slip. Larger throttle openings and the change is much more positive. I have tried all sorts of combinations of kickdown cable lengths.
It's vertually a new box ( 17,000) it gives the impression that the line pressure is low at low revs, ???
Any ideas would be most welcome, many thanks.
Cheers.
Geoff.

[jeremy]

This sounds similar to a problem I had on my second XJ^ which has a Borg Warner 65 or 66 box. The best feature of its predecessor was its autobox which would change rapidly and smoothly - and when I looked underneath it was obvious the thing had been adjusted as the adjusters and surrounding area was clean.

The second car was a series 3 which had much the same transmission and a fuel injected engine but was slow on changing down to second. I duly adjusted it and it was as good as the first - on part throttle kickdown at about 30 you could get it to change down and back up again in about a cars length.

What I think was happening was that the thing took time to produce enough high pressure fluid to fill the cylinder as it took up the slack. The adjustment instructions were to tighten a bolt to a specified torque (The figure was useless - it simply went dead tight) - then undo it 1/3rd turn to create a clearance. In fact the adjuster did up many turns - so backing it off 1/3 of a turn didn't seem like compromising the adjustement and I probably undid it 1/2 just to be safe.

I know your BX has a ZF transmission but I see from the official Citroen manual that there is an external brake band adjuster and that the instructions are similar - tighten to a torque and back off this time by 2 turns.

Download the manual here:

http://www.rwbsmith.plus.com/citroen2/

The bit you want is pages 36 and 37.

[AlanS]

There's a few basics associated with autos on BXs that have to be followed.
When you "drain" an auto, only a % of fluid comes out and I have found that 2.5 litres is the normal refill level after a fluid drain unless of course the box is completely out and drained manually or as some specialists do, pumped out.
The changes being snappier on lower gears than the higher ones is fairly common, but I find the BX auto a great drive as I tend to drive an auto like playing an instrument by varying the throttle to control the speed and style of gearchange. I'm no big auto fan, I have to be honest, but if I have to drive an auto, the BX is my preference due to the ability to do this.
Incorrect fluid (usually D111) can cause weird symptoms with the common ones being snatchy gearchanges, not wanting to stay in one gear at around 60 kph thereby flaring between 3rd & 4th and intermittent hanging on followed by a thunderous thud when downchanging. To correct the incorrect fluid, it takes at least 10 fluid changes over a short period of time to rid the box of the contamination by the other stuff.
Download a copy of the manual here:
http://www.rwbsmith.plus.com/citroen2/Gearbox/

and print off a hard copy (too bloody hard scolling up and down whilst squinting at a screen and trying to remember what you went there for in the first place) and read and follow to the letter the info regarding adjustment to the kickdown. It has to be done relative to the accelerator setting and has 2 measurements (when hot) for fully open and fullt closed (1mm and 39mm from the stop on the kickdown cable IIRC) and the kickdown adjustment I have heard being blamed for a goodly % of failures with these boxes.
There is also a filter in these that can cause some strange symptoms. It requires removal of the hydraulics at the front (or at least unbolting to push aside for convenience sake and I think we may also have removed the driveshaft but stand corrected on that. To do this, you remove the pan off the bottom of the tranny (there's a little magnet floating around in there which is possibly covered in metal filings; wash it off and throw it back in first up.) From the front of the car, look to the right and you'll see a rectangular box held in by about 2 dozen torx headed screws. Grab a shoe or cereal box and punch holes in and mark with a pen so the screws can be relocated back exactly where they came out because there's different sizes amongst them and one in the wrong spot can spell disaster for the transmission.
Once off, you will see the filter inside it. It's made from that material type of stuff that the filters inside the LHM tank are made of, so blocks real easily. It can be replaced or as we do, wash it in petrol and blow out with compressed air. That can make a big difference to changes also.

Trust that covers most of it,


Alan S

[docchevron]

Thanks for that Alan.

I cant see the brake band being out, although I did make the MAHOOSIVE error of putting D3 in it. Although I VERY quickley realised what I'd done, well actually dad did but....

I'm hoping most of that stuff is out now, although maybe more fluid changes are required.

I'm familiar with stripping the valve chest out, even though the box was built to spec it still had the wrong kickdown cable so I had to change it before the box ever went near the car.

I have to say that most of the ZF auto BX's I've driven are the same as dads, but maybe a bit of investigatoin is called for, that box cost a bl**dy fortune, and it's so**ing heavy, I dont really want to have to change it again!!

[AlanS]

A while back, someone posted a link to a Saab site about these boxes which are common to BX and Saab.
It was something to do wih replacing a spring that breaks in them as well as cleaning or replacing a plastic valve.
Apparently neither are expensive, just a b*****d to do.
I forwarded the link to a friend of mine as he is more into these autos than I am and hopefully, he'll be helping when we strip mine, but I didn't keep the record of where it is myself.
I'll have a yarn to him and see if he can send it to me and if he can, I'll post it; might be a good one to keep on file for future reference.

Alan S

[Geoffrey Gould]

Hello Alan and Jeremy thank you all. Just a little update the cable has been set up as accurately as possible and the fluid changed, a short road test taken and the result is that is is a bit better, still 'flares' 3 to 4 but with less of a thump. The band bid not need adjusting. The colour of the fluid was red-ish and did not smell too bad.
One thing is that Transmax 'M' has been discontinued unless you wish to get it from Castrol New Zealand. Three of the local shops have stopped stocking Dexron 11 and came out with the Dexron 111 is the best and latest one. Great.
Thanks again will keep you posted and will be most interested as regards what turns up about the spring and valve jobby.
Cheers.
Geoff.
If only it had a B W model 8 that really is a tough old box.

[AlanS]

They never learn some of these characters do they?
We had a case over here where a guy who is an engineer bought a Xantia that had just been serviced and when he checked the records, found it had been poisoned with D3.
He approached the servicing dealer (a full Cit dealership) and asked for it to be pumped out and replaced. The dealer refused saying it was Citroens recommendation. He then rang the Cit importers who told him this cock and bull story about D3 being the upgraded version of D2, so he then wrote to both asking for a written guarantee that using D3 in his transmission wouldn't do it any harm and that if the box were to fail prematurely and the fault was found to be caused by this fluid, that they would take full responsibility for the costs to rebuild it.
They refused and subsequently put a warning on their website about use of incorrect fluids in the transmissions.
There are fluids coming on the market which are like a semi synthetic for gearboxes which are referred to as a "step down" fluid which are supposedly for use in either D2 or D3 recommended transmissions. One is made by Mobil and I think it may be called A220 or something like that.
I used it in a faulty box looking for an improvement, but it did not work well at all, so the jury's still out on a substitute for D2 although I understand Total make a D2 under another code, so that may be worth pursuing.
Getting back to the original problem though Geoff. If it's still a bit harsh on teh change, try lowering the fluid level by around 500 mls and see what happens.

Alan S