What is the Moss gearbox and why is it disliked?

The Moss four-speed fitted until September 1965 has no synchromesh on first gear and a heavy, slow, notchy shift. It is durable but demands a deliberate driving style, and worn synchromesh or noisy bearings are common.

Which Jaguar Mk2 manual gearbox is best?

The all-synchromesh Jaguar four-speed introduced in September 1965, standard on the 240 and 340, is much nicer to use than the earlier Moss box — ideally with Laycock overdrive.

Is a Mk2 automatic worth having?

The later Borg-Warner BW35 is smooth and long-lived, relaxing in traffic and it spares the heavy clutch. It feels lazy compared with a manual, so it suits gentle touring rather than brisk driving.

Should I fit a five-speed gearbox to a Mk2?

A five-speed conversion gives modern ratios, a light shift and relaxed cruising, and is widely accepted as a sympathetic upgrade — often the best answer if the original box needs rebuilding anyway.

Knowledge base

Manual, Overdrive or Automatic: Which Jaguar Mk2 Gearbox?

By Jon Cosson — classic-car owner, North Yorkshire, near Thornton-le-Dale

Gear lever and transmission tunnel inside a classic Jaguar Mk2 saloon — Illustrative image — not a photograph of 873 EUT; the car itself appears on the build page.

Two Mk2s with the same engine can feel like different cars depending on what sits behind it. The transmission shapes the whole character of the drive, and it is one of the few specification details genuinely worth being fussy about when you buy.

The Moss four-speed (to September 1965)

Early cars use the Moss box. It is strong and it will outlive most of the car, but it has no synchromesh on first gear, and the shift is heavy, slow and notchy — you change gear deliberately, pausing between movements, and let the box set the pace. Drivers who grew up with it speak of it fondly; drivers coming from anything modern find it hard work in town.

When inspecting one, listen and feel for weak or worn synchromesh (a crunch on the downshift into second or third), whine or rumble from worn bearings, and a lever that jumps out or refuses to engage cleanly. A rebuild is specialist work and not cheap, which is worth factoring into the price of any early car.

The all-synchromesh Jaguar manual (from September 1965)

From September 1965 Jaguar fitted its own all-synchromesh four-speed, and it became standard on the 240 and 340. Synchromesh on every gear, a lighter and quicker action, and a far more pleasant car in traffic. If you want a manual and are indifferent to build year, this is the one to look for — the single biggest driveability improvement Jaguar made to the model.

Laycock overdrive

Overdrive, operating on the upper gears, transforms the car as a long-distance machine: cruising revs drop, noise falls away, the engine relaxes and fuel consumption improves. On a manual Mk2 it is the option most worth having. Test it properly — it should engage and disengage promptly and cleanly, without slipping, thumping or dropping out on the overrun. Faults are often electrical or hydraulic (solenoid, switches, oil level and pressure) rather than terminal, but confirm rather than assume.

The Borg-Warner automatic

Automatics were popular when new, and remain a civilised choice. The early DG is the crude one — heavy, slow to shift and now the harder to support. The later BW35 is much better: smooth, durable and long-lived, and it also spares you the Mk2's notoriously heavy clutch. An automatic feels lazy next to a manual, and it blunts the car's performance, but for relaxed touring and modern queues it is easy to live with. Check the fluid: it should be red and clean, not brown and burnt-smelling, and shifts should be positive rather than slurred.

The modern option

If the original box needs a rebuild anyway, many owners take the opportunity to fit a five-speed conversion. It brings a light, precise shift, well-spaced ratios and a genuine overdriven top for motorway work, and the market treats it as a sympathetic improvement rather than a compromise.

One warning

Whatever the box, remember that on a Mk2 a slipping clutch is an engine-out job. Clutch condition is therefore a serious cost item, not a minor consumable — check for slip under load and for judder on take-up before you buy.

Which to choose

Best all-round: the all-synchromesh manual with overdrive, or a five-speed conversion.
For relaxed, mostly urban use: a healthy BW35 automatic.
For originality on an early car: the Moss box, accepted on its own terms.

As always, condition outranks specification — see the buying guide.

Specifications and dates varied through production and by market, so confirm details for a particular car against the workshop manual and the owners' clubs.

Common questions

What is the Moss gearbox and why is it disliked?: The Moss four-speed fitted until September 1965 has no synchromesh on first gear and a heavy, slow, notchy shift. It is durable but demands a deliberate driving style, and worn synchromesh or noisy bearings are common.
Which Jaguar Mk2 manual gearbox is best?: The all-synchromesh Jaguar four-speed introduced in September 1965, standard on the 240 and 340, is much nicer to use than the earlier Moss box — ideally with Laycock overdrive.
Is a Mk2 automatic worth having?: The later Borg-Warner BW35 is smooth and long-lived, relaxing in traffic and it spares the heavy clutch. It feels lazy compared with a manual, so it suits gentle touring rather than brisk driving.
Should I fit a five-speed gearbox to a Mk2?: A five-speed conversion gives modern ratios, a light shift and relaxed cruising, and is widely accepted as a sympathetic upgrade — often the best answer if the original box needs rebuilding anyway.