c-matic maintenance...

37dhw8

37dhw8

Member
Fellow Frogger
Joined
Jan 27, 2018
Messages
74
Location
melbourne, australia
hey froggers...

my 79 CX2400 has a c-matic transmission, and as a newbie to citroen cars and cars in general, i'm wondering what sort of preventative maintenance to undertake on the gearbox. are there filters etc i need to think about changing periodically ? ATF fluid - what's a safe replacement for the original total fluide-t ? and is there supposed to be a dipstick on the gearbox ? mine doesn't appear to have one...

my apologies for my lack of know-how in this area... but the only stupid question is the one that isn't asked.

thanks!

max.
 
Had a couple myself and they’re a great car!

Whilst some may say a c-matic combines the worst features of a manual gearbox with the worst features of an auto box, I’d disagree :) A well sorted one is good fun!

There is a filter and a Fluide T substitute trans oil (not sure which one) From memory the dip stick for the c-matic is
out of obvious sight near a crossmember - recommend a Haynes manual to assist with this (section 9):

1672f3971345da245ecb5403dfd30f8f.jpg


TBH if it’s working ok and the fluid level/color is ok I’d leave it alone and enjoy!



Sent from my iPhone using Tapatalk
 
Having owned one of blahblah's ex-C-matics for 11-12 years now, I'd concur with his comments. Lovely wafty cars. Mine was overhauled by him and his father and hasn't given a moment's trouble in the transmission department.

My good friend in Paris said, some years ago, "You have a C-matic? Does it work? Yes? Don't touch it!!" :)

Cheers
 
the biggest problem you will likely have is voltage drop the the C-matic solenoid. do NOT put dexron in it. I seem to recall it should be the old Ford type F fluid ( as it is similar to total T). I'm guessing these details have been lost in the crash way back. Hopefully someone else remembers!

seeya,
shane L.
 
There is a dipstick . It's bit hard to find. Have a iook from under the bonnet , down to the top of the gearbox. Pretty accessible once you locate it.
As I recall the fluid Is ford spec.
I used to use penrite fluid T untill they stopped making it. I rang Penrite but the tecnical guy was quite dismissive and unhelpful.
I then used castrol transmax z.
Expensive but excellent. If I still had a CX, I would be using a full synthetic atf. Probably Nulon. Any reputable brand with high spec would be fine. There is a filter too but I never changed it. I did enquire about getting one but the specialist citroen parts supplier didnt have any told me no need to change it.
I would be changing the cmatic every 20000 km, same time as the modern synthetic engine oil I used.
I am sure others will differ but thats what I used to do.

Sent from my LG-K520 using aussiefrogs mobile app
 
Thanks everyone for your help.

i've heard castrol transmax type f works well for c-matics, being a replacement for the old castrol tqf. can anyone vouch for this ?
 
Trans Max type F Fluid. Fit a check strap on the electro-valve solenoid to prevent the cap dropping. Can be made from thin sheet steel and must bolt on the studs that retain the electro-valve. It must pass over the plastic cap and not interfere with the wire connections on the cap! Dip stick is at the back of the diff housing. Filter is behind the large aluminium screw in plug on the front side of the gear case. Be careful when removing not to break the magnetic rod inside the filter housing. It is attached to the large aluminium plug. Filters are available from CX-Basis in Germany.
BTW the cap dropping on the electro valve means that the windings for the solenoid have also dropped internally. This causes a state whereby the armature of the solenoid, which acts onto a spool valve in the casing does not throw to the required extent. Therefore the spool valve will not correctly switch pressure in the torque converter to operate the clutch. This inturn makes it difficult to engage gears.
 
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I just got "C-matic oil" ("Fluide-T" substitute) from CX-Basis, cost € 8,31 per litre (about 13,3 AU $). On the last bottles I got the OEM label was still there showing it was made by German company Kompressol and called "Fluid ATF 415 A". The label says it's intended to use in "certain half- and fully automatic gearboxes, torque converters and power stterings in lorries, buses, construction- and industrial machinery"; as well as in "older ZF, MB and GM automatic transmissions". If you are going to import it from Germany you might as well by it from CX-Basis I believe.
"Fluide-T" that was originally reccommended is indeed an ATF - but there are an abundance of ways to make a semi-automatic or automatic transmission and they work in different ways. The C-matic is basically a 3 speed manual transmission with a torque converter replacing the clutch, a lot like Chrysler's "Presto-matic" aka. "Gyro-matic" semi-auto transmissions in the 1950's. (They had a fluid-coupling or a torque converter married to a manual gear-box).

The only thing I have read "everywhere" is that one shold NOT use Dexron III. It has something to do with "friction modifiers" present in Dexron III that's doesn't go well with the C-matic. If the Dexron is to "slippery" or "grippy" I'm not sure about, I think the latter as the Hydramatioc gearbox has a lot of "friction bands" inside that probably are depending on - uhh - friction. If you source it locally I would have gone to a specialist in oils for heavy equipment like tractors etc. and asked them, explaining what the C-matic is. They should be able to help.
 
Kim_Jarre said:
I just got "C-matic oil" ("Fluide-T" substitute) from CX-Basis, cost € 8,31 per litre (about 13,3 AU $). On the last bottles I got the OEM label was still there showing it was made by German company Kompressol and called "Fluid ATF 415 A". The label says it's intended to use in "certain half- and fully automatic gearboxes, torque converters and power stterings in lorries, buses, construction- and industrial machinery"; as well as in "older ZF, MB and GM automatic transmissions". If you are going to import it from Germany you might as well by it from CX-Basis I believe.
"Fluide-T" that was originally reccommended is indeed an ATF - but there are an abundance of ways to make a semi-automatic or automatic transmission and they work in different ways. The C-matic is basically a 3 speed manual transmission with a torque converter replacing the clutch, a lot like Chrysler's "Presto-matic" aka. "Gyro-matic" semi-auto transmissions in the 1950's. (They had a fluid-coupling or a torque converter married to a manual gear-box).

The only thing I have read "everywhere" is that one shold NOT use Dexron III. It has something to do with "friction modifiers" present in Dexron III that's doesn't go well with the C-matic. If the Dexron is to "slippery" or "grippy" I'm not sure about, I think the latter as the Hydramatioc gearbox has a lot of "friction bands" inside that probably are depending on - uhh - friction. If you source it locally I would have gone to a specialist in oils for heavy equipment like tractors etc. and asked them, explaining what the C-matic is. They should be able to help.
Click to expand...
I'll say it again! Castrol Transmax Type F ------It is a direct replacement for the previous Castrol TQF. Both work very well in a C-Matic, Smooth synchro changes and excellent response from the clutch in the torque converter.
If the trans has not been changed before it will need a series of several changes to remove built up detritus from around the clutch seal O ring in side the torque converter. Do not listen to anyone who tells you to leave it alone if it is working well. It will need regular fluid changes to keep it clean. The filter is there for a reason and so is the magnetic rod in the filter housing. These need to be CLEAN!
 
I remember my parents going on holiday in our new CX 2400 with a C-Matic box.
An 'urgent' phone call sent me on a 200-mile round trip to rescue them...
'No Dad, the side lights that won't switch off and you're worried about the battery going flat? I'ts just the SUNSHINE'
I really miss him.
 
okay thanks for your help everyone, I put it together with the 2 large springs inside each other and put the spool with the spring on the top side put it all together after fixing the initial wiring problem and it all works as it should

A big thankyou to those who responded
 
If there is a direct replacement for total T (I’d tend to believe in trans max f if Gerry says it) then use that, and just that... seen a few of these cars put off the road because people had used friction modifying fluids... the dipstick is impossible to see, even if you know where you’re looking, but it you take the spare wheel out and lean over the left guard with your arm under the big brown crossmember towards the center of the car, you’ll eventually find it... doesn’t help that it’s just a bit of bent wire with a loop on it and it’s only 100mm long!
If it’s workomg well, regular fluid and filter changes are all it should need... if it’s getting a bit sticky to change gears, there are a few things to make sure of. The voltage drop to solenoid is a big issue, if the wiring is still standard, you can upgrade it. Is important to get full battery voltage (also important for charging system to be in order, especially if you stil have an external rectifier alternator). There’s a set of switching contacts on the top of the box, these are low current and switch ground to the coil of the relay that controls the solenoid, and when all closed in series activate the solenoid... when the gear stick is moved or in neutral they close to allow gear change. They need to be clean though, although don’t often go ot or adjustment. These contacts also control the circuit that supplies the relay that controls the starter motor, to prevent starting the car in gear, if it’s been wired to allow you to start in gear, probably worth rectifying. Can be a good idea to upgrade the wires carrying current from the relay to the solenoid too and make sure the supply is strong.The gear linkages can also go bad. There’s one nylon bush that will make it almost impossible to get into gears when it wears. Again, this is located directly below the cross member, and isn’t easy to get to.
 
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