The Car
Triumph Stag: Manual vs Automatic
Both were factory options. Most enthusiasts prefer the 4-speed manual with Laycock overdrive for the driving experience; the Borg-Warner Type 35 3-speed automatic suits the Stag's grand-tourer character and is a durable, low-drama choice. Manual/overdrive cars typically sit at the top of the values band.
At a glance
| Manual (+ Overdrive) | Automatic | |
|---|---|---|
| Unit | Triumph 4-speed, Laycock overdrive on 3rd & 4th (optional) | Borg-Warner Type 35, 3-speed |
| Ratios | 4 forward, plus overdrive step | 3 forward |
| Character | More involving; quieter cruising with overdrive engaged | Relaxed grand tourer; suits the V8's torque |
| Common faults | Overdrive solenoid, switch and wiring; worn synchros on tired boxes | Generally durable; watch for slipping, harsh shifts, cooler-line leaks |
| Market value | Usually a premium, particularly for original manual/overdrive cars | Typically offers better value in the UK enthusiast market |
The manual with Laycock overdrive
The standard box is a 4-speed manual. Overdrive was a popular factory option and operates on 3rd and 4th via a column or dash switch, giving an effective six ratios and materially lowering motorway revs. The engagement should be crisp; hesitation, drop-out or a refusal to engage typically points to the solenoid, its wiring, or the isolator switch rather than the overdrive unit itself.
On a test drive, engage and disengage overdrive several times in both 3rd and 4th, at temperature. Check for clean synchro on 2nd under a firm downshift, and listen for bearing whine that changes with clutch position.
The Borg-Warner 35 automatic
The Type 35 is a conventional 3-speed torque-converter automatic used across many British cars of the era. It is well suited to the Stag's torquey V8 and is generally the less troublesome transmission choice. Shifts should be smooth but positive; look for delayed engagement into Drive or Reverse, slurred or slipping upshifts, and any red or brown staining under the sump or around the cooler lines to the radiator.
Fluid should be bright red and not smell burnt. A neglected auto that is otherwise working can often be recovered with a fluid and filter service; a slipping or noisy box is a full rebuild.
Which should you buy?
- Buy manual/overdrive if you value driver involvement and long-term resale. Budget for the overdrive electrics to need attention at some point.
- Buy the automatic if you want a relaxed touring car, lower purchase price, and one fewer thing to fault-find. The Borg-Warner is a known quantity.
- Do not plan a conversion. Manual conversions are involved and rarely add value beyond the cost. Buy the specification you want.
Frequently asked questions
Is the Triumph Stag automatic or manual?
Both were offered from the factory. The standard car was a 4-speed manual (with optional Laycock overdrive), and the Borg-Warner Type 35 3-speed automatic was a factory option. Manual-with-overdrive is the more common survivor in the UK; automatics were more popular in export markets.
Which is more reliable — the Stag manual or the automatic?
The Borg-Warner 35 is a robust unit and, in service, is generally the less troublesome of the two. The manual gearbox and its overdrive are also durable when maintained, but the overdrive solenoid, wiring and switch are common fault points.
Does a manual Stag with overdrive command a higher price?
Yes, in most markets. A manual/overdrive car is usually the most sought-after specification and typically sits at the top of the values band. Automatics are less popular in the UK enthusiast market and can offer better value.
Can a Stag automatic be converted to manual?
It is possible using period-correct parts (gearbox, bellhousing, pedal box, propshaft, console) but it is a substantial job. Retaining the original transmission is usually preferred for originality; buy the specification you want rather than plan a conversion.