Seal for drive shaft gearbox side with double universal joint. Suitable for Citroen 2CV4 + 2CV6
(starting from year of construction 1961 about 1973). The seal is of paper. Or. No. AM373-77. Inside diameter 82mm. Outside diameter 118mm.
transmission for Citroën 2CValt
13 Articles
Seal for drive shaft gearbox side with double universal joint. Suitable for Citroen 2CV4 + 2CV6
(starting from year of construction 1961 about 1973). The seal is of paper. Or. No. AM451-72A. Inside diameter 82,5mm.
Spring suitable for the gear lever in the old gearbox, for Citroen 2CV from the fifties + sixties
es (gearbox shifter rod is rear at the gearbox). The spring is mounted under the gearbox cap. Or.Nr.A33497
Gearbox cap seal for Citroen 2CV/AMI6, Dyane. Suitable for the old gearbox, Installed off about
year of construction 1963.
Gearbox Oil addetive, 20g. Suitable for 1 liter transmission oil. This additive has been specially
developed for manual and differential transmissions. The product significantly reduces wear and reduces temperature peaks which means quieter running, softer gear changes and better fuel-efficiency.
M9, stud bolt, for the mounting of the drive shaft at the gearbox. Suitable for Citroen 2CV +
Citroen DS. Measurement: M9x42mm.
Oil drain screw magnetically, suitable for Citroen 2CV, HY, DS, 11CV (with oil pan out of sheet
metal). Interior square. The suitable tool has our number 20221. Or. No. A1321M, thread M16x1,5x20
Gasket for oil drain plug for 2CV6, BX, XM, 204, 203, 304, 404, 504. inlet + exhaust screw
measure: 16,3x22x2mm. Version C, curved with a seal inside. (PTFE)
Shifter rod bellows on the gearbox. Suitable for Citroen 2CV, early years of construction. Not
fitting for 2CV6! Or. No.: A33462
Speedometer cables bush (guide speedometer cable) in the gearbox, suitable for 2CV old + 2CV4
Reproduction. (The speedometer cable is held with a clip in the gearbox). Not suitable for 2CV6.
Identification plate green, for Citroen. 78x40mm. 2 bores. (Metal). The green identification plates
were often used for gearbox identification!
13 Articles
Gearboxes suitable for early and mid-production Citroën 2CV sedans, up until the introduction of the 2CV6, differ significantly from later models in technical terms. Accurate identification is particularly important when it comes to gear ratios, the braking system, the clutch, the drive shafts, and the speedometer cable drive.
Citroën 2CV Sedan Transmissions Up to the 2CV6
Early Citroën 2CV sedans differ significantly from the later 2CV6 in technical terms. There are important differences, particularly in the transmission, braking system, engine, and gear ratios. Anyone looking for a transmission for an early 2CV, or planning to rebuild or install one, should therefore not rely solely on the external design.
The early 2CV sedan family includes, among others, the 2CV A, 2CV AZ, AZL, AZLP, AZAM, as well as later transitional models prior to the introduction of the 2CV6. These vehicles were built with smaller engines, including 375 cc, 425 cc, and later 435 cc. As a result, the transmissions were also tuned differently than in the later 2CV6 with a 602 cc engine.
A transmission from a later 2CV6, Dyane, Ami, or Fourgonnette may appear mechanically similar, but it is not automatically compatible. The decisive factors are always the engine, year of manufacture, clutch, brake system, drive shafts, speedometer cable drive, and gear ratio.
Which 2CV sedans are being referred to?
This text refers to the 2CV sedans prior to the 2CV6 generation. These primarily include the classic early and mid-range models.
| Model | Technical Classification |
|---|---|
| 2CV A | Early version with 375-cc engine |
| 2CV AZ | Later early version with 425 cc engine |
| 2CV AZL | more comfortably equipped AZ variant |
| 2CV AZLP | AZL with trunk lid |
| 2CV AZAM | Comfort-oriented version with technical detail changes |
| Later 425-cc models | with modified details depending on the year of manufacture |
| Early 435-cc models / versions similar to the 2CV4 | Transition to the later model generation |
Important: The 2CV4 with a 435-cc engine is not the same as an early 425-cc 2CV. Even though both vehicles appear similar, the engine, body components, and, in some cases, the technical tuning differ.
Basic design of the early 2CV transmission
The transmissions in early 2CV sedans are part of Citroën’s A-model technology. They are manual 4-speed transmissions with reverse gear. Second, third, and fourth gears are synchronized. First gear is not synchronized.
This means: First gear should only be engaged when the vehicle is stationary. If first gear is engaged while the vehicle is rolling, significant shifting noises may occur. This is a design feature of these transmissions and does not necessarily indicate a defect.
If first gear is difficult to engage while the vehicle is stationary, it may help to briefly shift into second gear first and then into first gear. This allows the gears to align better.
Why early 2CV transmissions should not be equated with 2CV6 transmissions
The later 2CV6 has a significantly more powerful 602-cc engine. The early 2CV sedans, on the other hand, were built with significantly smaller engines. Therefore, the demands placed on the transmission are different.
A transmission for a 375-cc or 425-cc engine must be matched to the lower engine power. A transmission with too long a gear ratio can cause the vehicle to feel sluggish, accelerate poorly, and lack sufficient power on inclines.
A 2CV6 transmission may appear mechanically similar, but it is not automatically suitable. In particular, the gear ratio, clutch, brake system, and drive shafts must be thoroughly inspected.
| Range | Early 2CV Sedan | Later 2CV6 |
|---|---|---|
| Engine | 375 cm³, 425 cm³, later 435 cm³ | 602 cc |
| Engine power | significantly lower, 9–21 hp | higher, 27–29 hp |
| Transmission tuning | Designed for small engines | tuned for more powerful engines |
| Braking system | Always drum brakes | drum or disc brakes depending on the model year |
| Hydraulic system | DOT / Lockheed for drum brakes | DOT / Lockheed or later LHM for disc brakes |
| Driving characteristics | Slow, low torque, light | More powerful and better suited for everyday use |
Engine and appropriate transmission ratio
Engine selection is particularly important for early 2CV sedans. The small engines have low power and require a transmission ratio that matches them.
| Engine | Typical classification | Significance for the transmission |
|---|---|---|
| 375 cm³ | Very early 2CV A | requires very precise short-ratio gearing |
| 425 cm³ early | 2CV AZ / AZL | Different tuning than later models |
| 425 cm³ late | Improved depending on year of manufacture | Check technical details carefully |
| 435 cm³ | 2CV4-style version | not to be equated with 425 cm³ |
| 602 cm³ | Later 2CV6 | Significantly different transmission calibration |
Especially with the early 375-cc and 425-cc models, one should not install just any later transmission. An incorrectly matched transmission can significantly worsen handling.
Gear ratio for early 2CV sedans
The gear ratio determines how well the vehicle accelerates, how powerful it is on hills, and how high the engine RPM is at speed. For early 2CV sedans, a suitable gear ratio is particularly important because engine power is limited.
A long-ratio transmission may feel smoother on flat roads, but is often unsuitable for small engines. The engine then lacks the power to accelerate the vehicle smoothly or handle inclines.
A shorter-ratio transmission is better suited to small engines. It provides better power delivery, albeit at higher RPM.
| Transmission Type / Model | Character | Effect in practice |
|---|---|---|
| Early 2CV A | Very well-suited to low engine power | necessary for adequate propulsion |
| 2CV AZ / AZL | Suitable for the 425-cc engine | Better balanced for early sedans |
| AZAM | More comfort-oriented, but still note the low engine power | precise matching is important |
| 2CV4-style version | Suitable for the 435-cc engine | not to be equated with early 425 models |
| 2CV6 transmission | Designed for 602 cm³ | may be too long or unsuitable for small engines |
| Ami / Dyane transmission | Longer depending on the model | usually requires careful inspection for early 2CVs |
For an original early 2CV sedan, a transmission that matches the specific model is the best choice. A later-model transmission can make the vehicle technically roadworthy, but often alters its character and suitability for everyday use.
Early 2CV transmissions: Brake system, modifications, and typical weak points
Drum brake transmission on early 2CV sedans
Early 2CV sedans have internal front drum brakes mounted on the transmission. This braking system is part of the classic DOT/Lockheed system.
Typical features:
| Feature | Early 2CV drum brake transmission |
|---|---|
| Front wheel brake | Internal drums on the transmission |
| Brake fluid | DOT / Lockheed |
| Handbrake | acts on the front drums |
| Transmission housing | without mounting for disc brake calipers |
| Used | typical for early 2CV sedans |
For early 2CV sedans, special care should be taken to ensure that the transmission is compatible with the existing drum brake system. A later-model disc brake transmission will not fit without extensive modifications to the original brake system.
Disc brake gearboxes are not found on early 2CV sedans
Later A-models and later 2CV6 versions may be equipped with internal disc brakes. These use LHM, i.e., green mineral hydraulic fluid.
However, this technology is not typical for early 2CV sedans up to the 2CV6. If an early vehicle has been equipped with a disc brake system, it is a conversion that must be carefully inspected.
Important: LHM and DOT/Lockheed brake fluid must never be mixed. The seals, boots, and brake components are designed for different fluids. Mixing them can cause serious damage to the brake system.
Can a later 2CV6 transmission be installed in an early 2CV sedan?
A later 2CV6 transmission may function similarly in some cases. Nevertheless, such a conversion is not technically recommended without a thorough inspection.
Before installation, at least the following points must be checked:
| Checkpoint | Why is this important? |
|---|---|
| Engine | Small engines require the appropriate gear ratio |
| Gear ratio | affects acceleration, torque, and hill-climbing ability |
| Braking system | Drum or disc brakes must be suitable |
| Brake fluid | Do not mix DOT / Lockheed or LHM |
| Clutch | Note the model year and model |
| Drive shafts | Check flanges and model |
| Speed sensor cable drive | May vary depending on the transmission |
| Handbrake | Depends on the brake system and transmission |
| Authenticity | Early models otherwise lose technical authenticity |
For an early 375-cc or 425-cc 2CV, a later 2CV6 transmission is not the ideal solution. The gear ratios may be too long or technically unsuitable.
Can Dyane, Ami, or Fourgonnette transmissions be used?
Transmissions from the Dyane, Ami, or Fourgonnette belong to the same A-model family. They may look similar on the outside and be partially compatible. Nevertheless, they often differ significantly in gear ratios, braking system, and design.
An Ami or Dyane transmission is often designed for more powerful engines or comfort-oriented driving. A Fourgonnette transmission may be geared toward commercial vehicles. This may be unsuitable for an early 2CV sedan with a small engine.
Before installation, always check the engine, year of manufacture, brake system, clutch, drive shafts, and speedometer cable.
Reverse gear in early 2CV transmissions: use only briefly and slowly
The reverse gear in early 2CV transmissions is intended for maneuvering. Prolonged reverse driving, high RPMs, or heavy loads should be avoided.
With A-model transmissions, it is known that prolonged or forceful reverse driving can lead to a jam. The cause is usually not directly related to reverse gear itself, but rather to a component in the area of the sliding sleeve for 2nd and 3rd gears.
There is a locking or threaded bushing located there. If this bushing comes loose, the sliding body can shift too far. This can cause shifting components in the transmission to jam. The transmission then behaves as if two gears were engaged at the same time.
Why can an early 2CV transmission lock up after driving in reverse?
When driving in reverse, different forces act on the transmission than during normal forward driving. If you drive in reverse for a long time, with a lot of throttle, or under heavy load, unfavorable stresses are placed on the shift mechanism.
Especially in old, worn, or previously repaired transmissions, a retaining clip can come loose. As a result, the sliding sleeve can shift out of its intended position. In the worst-case scenario, the transmission locks up completely.
Drive in reverse only slowly, for short distances, and without heavy loads.
The following should be avoided in particular:
- long periods of reverse driving over yard or garage driveways
- Reversing at high engine speeds
- Heavy acceleration in reverse
- Reversing on inclines
- Forcibly maneuvering the vehicle when it is stuck
- Rocking the vehicle back and forth between forward and reverse gears
Typical signs of a seized early 2CV transmission
The following symptoms may indicate a jam or damage in the transmission:
| Symptom | Possible meaning |
|---|---|
| A metallic noise occurs after driving in reverse | A safety device or shift component may have come loose |
| The vehicle will not move | The transmission may be internally locked |
| The clutch engages, but the drive remains locked | Probable transmission failure |
| The shift lever feels unusual | Shift forks or shift sleeves may be misaligned |
| The transmission feels as if two gears are engaged | Shift components may be jammed |
| The wheels lock up when starting | Possible internal transmission lockup |
In this situation, do not force the gearshift, attempt to drive off, or use the starter motor. Doing so may cause further damage to the gears, shift sleeves, or shift forks.
What to do if the early 2CV transmission locks up?
If the transmission locks up after driving in reverse, the vehicle should be secured immediately and not moved any further.
Recommended procedure:
- Secure the vehicle to prevent it from rolling away.
- Do not shift gears or drive off.
- Do not force the gearshift lever.
- Do not use the engine or starter to release the lockup.
- Remove the upper transmission cover.
- Check the position of the shift sleeves and shift forks.
- Position the loosened retaining bushing correctly and secure it.
- Check the transmission fluid for metal particles.
- Carefully check all gears before taking a test drive.
With a bit of luck, the cause can be checked and fixed through the upper transmission cover. Whether that is sufficient depends on whether consequential damage has already occurred.
When does an early 2CV transmission need to be removed?
Removal and complete disassembly are recommended if significant damage is visible or if the transmission continues to exhibit issues after the initial inspection.
| Findings | Recommendation |
|---|---|
| Retaining bushing severely damaged or loose | Disassemble and inspect the transmission |
| Teeth damaged or broken | Complete technical inspection required |
| Sliding sleeve damaged | Replace component |
| Shift fork bent | Inspect or replace shift fork |
| Metal particles in the oil | Clean and inspect the transmission |
| Squealing noises after repair | Check bearings, bevel gear, and ring gear |
| Gear pops out | Check the shift sleeve, detent, and bearings |
A loose bushing should not simply be screwed back in. It must be permanently secured. Depending on its condition, options include clean caulking, suitable threadlocker, or a professional mechanical lock.
Typical weak points in early 2CV transmissions
Early 2CV transmissions are robust, but often very old and have been used, repaired, or modified over the course of decades. Therefore, typical wear points should be carefully inspected.
Shifting problems and synchronizer rings
Cracking or sticking when shifting, especially between 2nd and 3rd gear or when downshifting from 3rd to 2nd gear, often indicates worn synchronizer rings.
| Cause | Description |
|---|---|
| Worn synchronizer rings | Common cause of shifting noises |
| Worn shift sleeve | Gear does not engage properly |
| Worn guides | Imprecise shifting feel |
| Incorrect or old transmission fluid | Poor shifting performance |
| High mileage | General wear possible |
Bearing noises
Howling, humming, or grinding noises should be taken seriously.
| Noise | Possible cause |
|---|---|
| Howling under load | Bevel gear, ring gear, or bearing |
| Rattling at idle | Input bearing, primary shaft, or clutch area |
| Roaring in all gears | Main bearing or differential bearing |
| Noise only in one gear | Gear pair or gear bearing |
| Loud howling during load changes | Wear or incorrect adjustment |
Leaks
Leaks are common in older 2CV transmissions.
| Location | Possible cause |
|---|---|
| Output flanges | Hardened oil seals or worn-in running surfaces |
| Shift cover | Old gasket |
| Speedometer cable drive | Defective sealing ring |
| Drain and fill plug | Old sealing rings |
| Case seam | Inadequate sealing following a previous repair |
| Collar area | Age-related cracks or leaks |
Transmission oil for early 2CV sedans
For many transmissions in the A-model family, approximately 0.9 liters of transmission fluid is required. However, depending on the early model year and version, the fluid level should always be checked according to the respective technical specifications. The correct fluid level is generally reached when oil leaks out of the side check port.
Recommendation for normal road use:
| Point | Recommendation |
|---|---|
| Quantity | usually approx. 0.9 liters; check depending on model |
| Viscosity | SAE 75W80 |
| Specification | Mineral GL-4 gear oil |
| Filler level | until oil leaks from the check port |
| Check | Check regularly |
| Not recommended | Engine oil, ATF, or very thin low-viscosity oils |
If the history is unknown, the transmission fluid should be changed and checked for metal particles, water, or a burnt smell.
Inspect early 2CV transmissions before installation or repair
Before installation, purchase, or repair, a transmission for early 2CV sedans should be thoroughly inspected. Many vehicles have been modified over the years or equipped with components from other A-series models.
Important checkpoints:
- Which 2CV model did the transmission originally belong to?
- Is the transmission compatible with a 375 cm³, 425 cm³, or 435 cm³ engine?
- What is the gear ratio of the transmission?
- Is it a drum brake transmission?
- Is the brake system compatible with the DOT/Lockheed system?
- Are the clutch, drive shafts, and speedometer cable compatible?
- Does the parking brake mechanism fit?
- Are there any shifting problems or noises?
- Are there any visible leaks?
- Is the correct transmission fluid used?
- Has the vehicle already been technically modified?
- Is the desired modification technically feasible or only mechanically possible?
FAQ on early 2CV transmissions up to the 2CV6
Which transmission fits in an early 2CV sedan?
That depends on the model, year of manufacture, engine, and braking system. A 2CV A with a 375 cc engine requires a different setup than a later 2CV AZ or a model similar to the 2CV4 with a 435 cc engine.
Is a 2CV6 transmission suitable for an early 2CV?
A 2CV6 transmission may be mechanically similar, but it is not automatically compatible. The gear ratio, brake system, clutch, drive shafts, and speedometer cable drive must be carefully checked.
Why is the gear ratio so important in early 2CV models?
The early 375 cc and 425 cc engines have low power output. A gearbox with too long a gear ratio can make the vehicle sluggish and impair its hill-climbing ability.
Does the early 2CV already have disc brakes?
No, early 2CV sedans have internal drum brakes on the transmission. Disc brakes are found on later models and would require a conversion on early vehicles.
What brake fluid is used in early 2CV sedans?
DOT/Lockheed brake fluid is used in the classic drum brake systems. LHM is used in later disc brake systems and must not be mixed with DOT/Lockheed.
Why does 1st gear make a clunking noise when engaged?
First gear is not synchronized. It should only be engaged when the vehicle is stationary. Shifting noises when engaging while rolling are possible due to the design.
Why can the transmission lock up after driving in reverse?
During prolonged or heavy-load reverse driving, a retaining bushing in the area of the sliding sleeve may come loose. This can cause shifting components to jam and the transmission to lock up.
How should reverse gear be used?
Reverse gear should only be used slowly, briefly, and without heavy loads. It is intended for maneuvering, not for extended periods of driving in reverse.
What is particularly important with a modified early 2CV?
When modifying a vehicle, the engine, transmission, brake system, clutch, drive shafts, speedometer cable drive, and brake fluid must all be considered together. Just because a part can be mechanically installed does not automatically mean it is technically compatible.
Summary
Early Citroën 2CV sedans, up until the introduction of the 2CV6, require a particularly precise transmission configuration. Models such as the 2CV A, AZ, AZL, AZLP, and AZAM were built with smaller engines and are not directly comparable to the later 2CV6.
A transmission must always match the engine, year of manufacture, brake system, and intended use. Especially for 375-cc and 425-cc vehicles, the correct gear ratio is crucial to ensure the vehicle accelerates sufficiently well and does not become too sluggish on hills.
Early 2CV sedans typically have drum brake systems with DOT/Lockheed brake fluid. Later disc brake systems with LHM are not part of the original early 2CV technology and must be carefully inspected during conversions.
Reverse gear should only be used slowly and briefly for maneuvering. Prolonged or heavy-load reverse driving can cause components in the shift mechanism to loosen and the transmission to seize.
Every early 2CV transmission should be carefully inspected before installation, conversion, or repair. This helps avoid mispurchases, consequential damage, and issues with the gear ratio, brake system, or shift mechanism.
Select your Citroen 
Please select your Peugeot 
Please select your Citroen Renault 
