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Details
| Specification | Value |
|---|---|
| Brand | MERTZ |
| MPN | m-s4321 |
| Fitting Position | Front Axle |
OE numbers (1)
Search by this OE number to find compatible parts
- AUDI / VW—431 399 151 D
Where this part fits
Original-fit position for OE 431399151D. The red ring marks where this part installs on the vehicle.
About this product
The MERTZ Mounting Automatic Transmission (M-S4321) is a professional-grade replacement component engineered for long service life and reliable operation across all conditions your vehicle encounters. The part is built to the following specification: Fitting Position: Front Axle, Material: 43, Mounting Type: Cast Iron. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. Verified to fit AUDI, VW models. All compatibility data is cross-checked against the TecDoc database — select your vehicle to confirm the part matches your specific engine and year. This part supersedes original equipment references: 001-10-29094, 00125, 00721053, 02.ST.326 and 60 more. Matching these numbers confirms a like-for-like replacement with no loss of function. MERTZ is a recognised supplier of automotive replacement components to independent workshops and dealer networks across Europe. All parts are sourced from authorised distribution channels and carry full manufacturer traceability — you receive exactly the same component supplied to professional garages and dealer workshops. If fitment or specifications do not match your vehicle, our technical team can help identify the correct alternative — use the vehicle selector or contact us with your VIN for a guaranteed-fit recommendation. Replacing worn components on schedule preserves your vehicle's safety, reliability, and resale value — and aftermarket parts from established brands deliver OEM-equivalent performance at a fraction of the dealer price. Every part is dispatched with tracked delivery and a 14-day money-back guarantee with hassle-free returns.
Suitable cars
Equivalent products (64)
Show all 64 OE numbers
Mounting Automatic Transmission MERTZ M-S4321 — compatible car models
| Car models | AUDI: 100 C2 Avant (435, 436), 100 C2 Saloon (431, 433, 434), 100 C3 Avant (445, 446), 100 C3 Saloon (443, 444), 200 C2 Saloon (437, 438), 200 C3 Avant (447, 448), 200 C3 Saloon (447, 448), 80 B2 Saloon (811, 813, 814, 819, 853), 80 B3 Saloon (893, 894, 8A2), 80 B4 Saloon (8C2) (+2 more); VW: PASSAT B1 Saloon (32), PASSAT B2 (32B), PASSAT B2 Saloon (32B), PASSAT B2 Variant (33B) |
|---|---|
| Engines | 1.6; 1.8; 2.1 5E; 2.1 Turbo quattro; 1.8 CC quattro (85Q); 1.6 TD; 1.9 TDI; 1.3 |
| Year of manufacture | 1973-2000 |
| Manufacturer article number (MPN) | M-S4321 |
| OE part numbers | 431 399 151 D |
Compatibility check
Loading vehicle data…
Please wait while we load vehicle compatibility information.Description and what's included
MERTZ m-s4321 . Fitting Position: VA. Material: 43. Mounting Type: 3
- 1x Mounting Automatic Transmission
Shipping, returns, warranty
Free UK delivery on orders over £99.00. Tracked standard shipping.
- Standard delivery: 4–8 business days
- Order before 5pm — ships the next working day
- Free returns within 14 days
- All parts backed by manufacturer warranty
Warranty: 12-month manufacturer warranty on all parts. 14-day money-back guarantee if the part doesn't fit your vehicle.
Frequently Asked Questions
Is this Mounting Automatic Transmission compatible with my car?
This Mounting Automatic Transmission fits AUDI, VW vehicles. Use the vehicle selector at the top of the page to check exact compatibility — enter your car's make, model, and engine for a confirmed fitment match. All fitment data is verified through TecDoc.
What specifications does this MERTZ Mounting Automatic Transmission have?
This MERTZ Mounting Automatic Transmission has the following specifications: Fitting Position: VA; Material: 43; Mounting Type: 3. Check the full specifications table above for complete details.
What OE part numbers does this Mounting Automatic Transmission replace?
This Mounting Automatic Transmission replaces OE part numbers: 431 399 151 D. Cross-reference these numbers with your vehicle's original part number to confirm compatibility.
How much does a Mounting Automatic Transmission cost?
This MERTZ Mounting Automatic Transmission is available for £5.99. Mounting Automatic Transmission prices vary depending on brand, specifications, and vehicle compatibility. MERTZ parts offer a balance of quality and value, backed by our 14-day money-back guarantee.
How do I know when to replace my Mounting Automatic Transmission?
Regular inspection of your Mounting Automatic Transmission is recommended as part of routine vehicle maintenance. Watch for changes in performance, unusual noises, or visual signs of wear. Consult your vehicle's owner manual for manufacturer-recommended replacement intervals specific to your make and model.
What tools do I need to replace a Mounting Automatic Transmission?
Tools required vary by vehicle make and model. Generally, a basic socket set, screwdrivers, and vehicle-specific tools may be needed. We recommend consulting a workshop manual for your specific vehicle, or having the Mounting Automatic Transmission fitted by a professional mechanic.
Can I use this part as a replacement for OE 431 399 151 D?
Yes, this MERTZ Mounting Automatic Transmission is a direct replacement for OE part number 431 399 151 D. It is manufactured to meet or exceed original equipment specifications, ensuring proper fitment and performance. All cross-reference data is verified through TecDoc.
Related categories
Common OE numbers for this part
Common original equipment numbers linked to stocked alternatives.
