The 1978 MG MGB has 11 automatic transmission parts with verified fitment on this page — 8 part types and 6 brands, covering the 1.8L L4 engine. Each part includes a manufacturer part number and application notes.
On the 1978 MG MGB, the automatic transmission covers the automatic gearbox and its supporting cast — filters, coolers, solenoids, mounts and torque-converter parts. Most of the listed parts are Transmission Fluid (3 parts), Extension Housing Seal (2 parts) and Filter (1 part). The other 5 part types cover the remaining 5 parts.
Every part on this page is matched to the 1.8L L4 — the only engine offered in the 1978 MG MGB.
The most listed brands for 1978 MG MGB automatic transmission parts are ATP (3 parts), VALVOLINE (3 parts) and WJB / INMOTION PARTS (2 parts), plus 3 more brands.
Each part number listed for the 1978 MG MGB opens a page with every vehicle that part fits.
Extension Housing Seal
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ATP | KO3 | 🇺🇸 US 🇨🇦 CA | Outer Diameter: 2.25" | View on Amazon |
| PIONEER | 759045 | 🇺🇸 US 🇨🇦 CA | Outer Diameter: 2.25" | View on Amazon |
This table covers the seals at the Extension Housing. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again.
2 Extension Housing Seal parts are listed for the 1978 MG MGB, from ATP and PIONEER.
This group includes ATP KO3 and PIONEER 759045.
Filter
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VARIOUS MFR | PTK22 | 🇺🇸 US 🇨🇦 CA | Trans. code 35 | View on Amazon |
This table covers the replacement filters for this application — the table heading and notes say which circuit. Typical signs include restricted flow — long cranking, weak airflow, or dirty fluid after a short interval. Seat the new filter so it cannot bypass, and use the grade the notes call for.
This group shows a single part: VARIOUS MFR PTK22.
Fluid Pan Gasket
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ATP | RG9 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the gaskets that seal the Fluid Pan. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for.
This group shows a single part: ATP RG9.
Fluid Pump Repair Sleeve
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WJB / INMOTION PARTS | WS99168 | 🇺🇸 US 🇨🇦 CA | Frontwith Borg-Warner T65 Transmission | View on Amazon |
This table covers the precision wear sleeves used to restore a transmission pump seal surface.
One part is listed for the 1978 MG MGB — WJB / INMOTION PARTS WS99168.
Fluid Pump Seal
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WJB / INMOTION PARTS | WS480479H | 🇺🇸 US 🇨🇦 CA | Frontwith Borg-Warner T65 Transmission | View on Amazon |
This table covers the seals at the Fluid Pump. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again.
One part is listed for the 1978 MG MGB — WJB / INMOTION PARTS WS480479H.
Transmission Fluid
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VALVOLINE | VV3246 | 🇺🇸 US 🇨🇦 CA | Max Life Multi-Vehicle or Maxlife Multi-Vehicle Full Synthetic ATF1 Quart | View on Amazon |
| VALVOLINE | 773775 | 🇺🇸 US 🇨🇦 CA | Max Life Multi-Vehicle or Maxlife Multi-Vehicle Full Synthetic ATF1 Gallon | View on Amazon |
| VALVOLINE | 881051 | 🇺🇸 US 🇨🇦 CA | Maxlife Multi-Vehicle Full Synthetic ATF5 Gallon Bay Box | View on Amazon |
This table covers the automatic-transmission fluids specified for this gearbox. Typical signs include harsh or delayed shifts, fluid that smells burnt, or a shudder at light throttle. Use exactly the specification in the notes. Automatic transmissions are unforgiving of the wrong fluid.
3 Transmission Fluid parts for the 1978 MG MGB come from VALVOLINE.
Listed part numbers: VALVOLINE VV3246, VALVOLINE 773775 and VALVOLINE 881051.
Transmission Fluid Additive
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ATP | AT202 | 🇺🇸 US 🇨🇦 CA | Automatic Transmission Fluid Synthetic Protectant | View on Amazon |
This table covers the conditioners and additives used with this transmission fluid.
This group shows a single part: ATP AT202.
Transmission Mount Bushing
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ENERGY SUSPENSION | 101101G | 🇺🇸 US 🇨🇦 CA | Performance PolyurethaneTransmission Buffer Mount Set | View on Amazon |
This table covers the Transmission Mount bushings. Typical signs include a clunk over bumps, or a torn or walked-out bushing you can see. Press the new bushing square. A cocked bushing will tear in a few thousand miles.
One part is listed for the 1978 MG MGB — ENERGY SUSPENSION 101101G.
Buying Automatic Transmission Parts for a 1978 MG MGB
On this vehicle, the automatic transmission covers the automatic gearbox and its supporting cast — filters, coolers, solenoids, mounts and torque-converter parts.
- Confirm you have the 1.8L L4 engine — every part on this page is matched to it.
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, replace the filter and pan gasket with every fluid service, and flush the cooler lines when replacing a failed unit.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Transmission Fluid and Extension Housing Seal .
Frequently Asked Questions
How many automatic transmission parts fit the 1978 MG MGB?
Our catalog currently lists 11 automatic transmission parts for the 1978 MG MGB across 8 subcategories and 6 brands, covering the 1.8L L4 engine. Each part is matched to the engine(s) it fits.
What are the signs of automatic transmission problems on a 1978 MG MGB?
Common symptoms include delayed or harsh engagement, slipping under load, fluid that smells burnt, or shuddering at light throttle around 40 mph. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, replace the filter and pan gasket with every fluid service, and flush the cooler lines when replacing a failed unit.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 1978 MG MGB was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 1978 MG MGB?
Every part on this page is matched to the 1.8L L4 engine. Then use exactly the fluid specification in the notes — automatic transmissions are the least forgiving component on the vehicle about fluid choice. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 1978 MG MGB
Automatic Transmission Parts for Other MG MGB Years
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Manufacturer names, model designations and part numbers are used for identification and fitment reference only. AutoFactsDB is an independent catalog and is not affiliated with, endorsed by, or sponsored by any vehicle manufacturer displayed on this page.