W123 automatic transmission leaking oil at the bellhousing? Seal A0049970547
Short answer: If automatic transmission fluid (ATF) drips from the bellhousing between engine and transmission on your Mercedes W123, W116, R107 or Strich-Acht (/8) with a W3/W4-generation automatic transmission, the shaft seal at the transmission input (pump or converter seal) is often leaking. The matching genuine part has the part number A0049970547 (44 × 60 × 8 mm). It is replaced with the transmission removed and the converter pulled off. We carry it as a genuine new old stock (NOS) part for 29,90 € per piece from stock.
In the morning there is a reddish spot under the car, the underside of the bellhousing is oil-damp, and the ATF level slowly drops. Many owners of a W123 automatic, a W116 S-Class or a 450 SL suspect the engine first. But if the leak is located exactly between engine and transmission, then besides the rear crankshaft seal, the shaft seal at the input of the automatic transmission is the main candidate. It seals the converter neck at the oil pump. In this guide you will find out how to narrow down the leak, which transmissions are affected and which part you need.
Symptoms
This is how you classify the fault before you plan the transmission removal:
| Symptom | Likely cause |
|---|---|
| ATF drips between engine and transmission at the underside of the bellhousing | Shaft seal at the transmission input (converter seal) leaking |
| Bellhousing oil-damp from below, ATF level drops over weeks | Possible: converter seal – narrow down the leak point by cleaning and observing |
| Oil at the bellhousing is dark and smells like engine oil | More likely the engine side, e.g. rear crankshaft seal – not the transmission input |
| Not to be confused with: Transmission oil leaks at the speedometer cable connection (manual transmission) | Different seal – see Transmission leaking oil at the speedometer drive |
| Not to be confused with: Oil is at the rear of the transmission, at the output toward the driveshaft | Output shaft seal – a different part (e.g. A 008 997 92 46, 40 × 62 × 10 mm) |
Causes
A shaft seal works with an elastic sealing lip that rests on the rotating converter neck with slight preload. On vehicles of this generation the seal has often been installed for decades. Heat from the engine and transmission, aged ATF and long periods of standing cause the material to harden. The lip then no longer seats cleanly, and oil is pushed past the converter neck into the bellhousing.
Testing it yourself
Start with the steps that cost nothing:
- Identify the transmission type. According to the product data, the seal A0049970547 belongs only to automatic transmissions of the W3/W4 generation (including 722.1). The later transmissions 722.3, 722.4, 722.5 and 722.6 use different seals – this check decides which part you need.
- Identify the oil. Take up a drop with a white cloth. ATF is usually reddish, aged ATF brownish; engine oil is mostly darker. This is how you can tell whether the leak comes from the transmission side or the engine side.
- Clean the leak area. Clean the underside of the bellhousing and the engine/transmission joint with brake cleaner and let it dry. Only on clean material can you see where the oil actually escapes.
- Test drive and visual inspection. After a drive, check again from below. If the fresh oil film forms at the underside of the bellhousing, the transmission input is the likely location. If it is at the rear of the transmission, the cause is a different seal.
- Check the ATF level and plan the replacement. Check the ATF level according to the manufacturer's specification and top up if necessary. If the diagnosis is confirmed, the seal is replaced with the transmission removed and the torque converter pulled off.
Solution
A hardened seal cannot be reconditioned – it is replaced. For this we supply the genuine Mercedes-Benz shaft seal with the part number A0049970547 (A 004 997 05 47, 44 × 60 × 8 mm) as an unused new old stock (NOS) part from inventory in the original box: light sealing lip, green-lacquered metal casing with Mercedes-Benz imprint, slight storage marks on box and casing. The successor number on record is A 017 997 32 47, the comparison number is Elring 319.104. Currently 3 pieces are in stock, the price of 29,90 € applies per pc.
Since removing the transmission is the greatest effort, replacement is especially worthwhile as part of a transmission overhaul or a converter replacement. Important: for W124, W201 and W126 from about 1983 with automatic 722.3/722.4/722.5, the seal A 013 997 09 46 applies according to the product data, not this part.
Mercedes converter seal automatic transmission 44 × 60 × 8 mm
Part number: A0049970547
Fits: W114/W115 · W123 · W116 · W108/W109 · R107/C107 (automatic W3/W4 only) · Condition: new old stock (NOS)
29,90 €
View productMore parts for your classic can be found in the categories W123, W116 and W107 / R107.
Compatible vehicles
Only with automatic transmission of the W3/W4 generation (including 722.1):
| Model series | Models per product data |
|---|---|
| W114 / W115 Stroke Eight (1968–1976) | 220 D, 230, 240 D, 280, 280 C, 300 D |
| W123 (1976–1985) | 240 D, 280 E, 280 CE, 300 D, 300 CD, 300 TD |
| W116 S-Class (1972–1980) | 280 S, 280 SE, 300 SD, 450 SE, 450 SEL, 450 SEL 6.9 |
| W108 / W109 (1971–1973) | 280 SE 4.5, 280 SEL 4.5, 300 SEL 4.5 |
| R107 / C107 (1973–1980) | 450 SL, 450 SLC |
| Does not fit | Manual transmissions as well as automatic transmissions 722.3, 722.4, 722.5 and 722.6 |
Automatic transmission leaking oil at the bellhousing? The seal is ready.
Genuine new old stock (NOS) part, part number A0049970547, for W3/W4 automatic transmissions – 29,90 € from stock
View nowFAQ
How do I know the converter seal on the automatic transmission is leaking?
Typical is automatic transmission fluid (ATF) dripping out between engine and transmission at the underside of the bellhousing. If, on the other hand, the oil is at the transmission output toward the driveshaft or at the speedometer cable connection, the cause is a different sealing point.
Does the seal A0049970547 also fit the W124, W201 or W126?
No, not for the automatic transmissions 722.3, 722.4 and 722.5. According to the product data, the W124, W201 and W126 from about 1983 have the seal A 013 997 09 46 at the transmission input. The part is also not intended for the five-speed automatic 722.6 or for manual transmissions.
Which vehicles are listed for the seal A0049970547?
Listed are vehicles with automatic transmission of the W3/W4 generation (including 722.1): W114/W115, W123 (including 240 D, 280 E, 280 CE, 300 D, 300 CD, 300 TD), W116 (including 280 S to 450 SEL 6.9), W108/W109 with 4.5-liter engine and R107/C107 450 SL and 450 SLC.
Can I replace the converter seal without removing the transmission?
No. The seal sits at the front in the oil pump or in the converter housing. Replacement is done with the transmission removed and the torque converter pulled off. That is why it makes sense to replace it at the same time during a transmission overhaul or a converter replacement.
What does the seal A0049970547 cost and what condition is it in?
The seal costs 29,90 € per piece with us. It is an unused genuine Mercedes-Benz new old stock (NOS) part in the original box; box and metal casing have slight storage marks.
KFZTeile-Thot is a specialist business for tested and refurbished Mercedes parts with its own test benches. More than 1,000 positive eBay reviews show that this standard holds up. Not sure which automatic transmission is in your car, or would you like to clarify the fit beforehand? Call us at +49 179 8991069 (Mon–Fri 8 am–6 pm) or write to us via our contact form – we'll check the fit against your chassis number free of charge.