What five-speed gearboxes fit a Jaguar Mk2?

The two common conversions are a hand-built Tremec/Borg-Warner T5 (from specialists, with an adaptor to the original bellhousing) and the Getrag five-speed from a 3.6 XJS. Both retain the original bellhousing.

Does a five-speed conversion require cutting the car?

Not usually — 'no-cut' T5 kits are designed to avoid it, though most conversions need minor tunnel clearance, a shortened propshaft and a gear-lever tweak.

Is a five-speed worth it on a Mk2?

For a car used on modern roads, yes — fifth gear drops cruising revs by around 20%, quietening the car and easing the engine, while gears one to four keep the original feel.

Do I keep my original clutch?

Some T5 kits use the original Jaguar 9.5-inch clutch; the Getrag route typically uses the XJS clutch. Confirm with your kit supplier.

Upgrade guide

Five-Speed Gearbox Conversions

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

Chrome gear lever with a black knob rising from the wood-and-leather console of a classic British sports saloon — Placeholder image — owner to replace with a photograph of the installed conversion.

The single most transformative upgrade for a fast-road Mk2 is a fifth gear. The original four-speed leaves the engine buzzing at motorway speed; a five-speed drops the revs, quietens the cabin and makes the car a genuine long-distance companion — without touching the character of the lower gears.

The original box

Early Mk2s use the Moss four-speed (non-synchro first); later cars the all-synchro four-speed, with overdrive optional. All are tall-geared for their day but leave no relaxed cruising gear.

The two popular routes

Tremec / Borg-Warner T5

The specialist favourite. New T5 boxes are hand-converted (Elite Racing Transmissions, M&C Wilkinson, The Driven Man and others) with an adaptor plate to the original Jaguar bellhousing, a locator ring, spigot bush, a speedo drive that accepts the original cable, a reverse-light switch and an output flange. Ratios are typically 2.95 / 1.94 / 1.34 / 1.00 with a 0.63 overdrive fifth (0.72–0.80 fifths are available and often recommended for the Mk2). First-to-fourth closely match the E-type four-speed, so the car feels right. "No-cut" kits avoid tunnel surgery.

Getrag five-speed

The budget/DIY route, using the Getrag box from a 3.6 XJS (you need the early XJS box that has the speedo drive), a conversion plate to the original bellhousing, a shortened propshaft and the XJS clutch. Fifth is around 0.86. Well-proven; a little more fettling.

Other routes exist (Toyota five-speeds, or an XJ6 four-speed-plus-overdrive).

What to expect fitting one

Most kits are close to bolt-in but expect some fettling: a little gearbox-tunnel clearance, a shortened propshaft, the gear-lever position, and matching the clutch. The reward is roughly a 20% drop in cruising revs.

On our car

873 EUT runs a Getrag five-speed — exactly this conversion — and it turns the Mk2 into a car you can happily cover big distances in. Read The Build: 873 EUT for the full specification.

Common questions

What five-speed gearboxes fit a Jaguar Mk2?: The two common conversions are a hand-built Tremec/Borg-Warner T5 (from specialists, with an adaptor to the original bellhousing) and the Getrag five-speed from a 3.6 XJS. Both retain the original bellhousing.
Does a five-speed conversion require cutting the car?: Not usually — 'no-cut' T5 kits are designed to avoid it, though most conversions need minor tunnel clearance, a shortened propshaft and a gear-lever tweak.
Is a five-speed worth it on a Mk2?: For a car used on modern roads, yes — fifth gear drops cruising revs by around 20%, quietening the car and easing the engine, while gears one to four keep the original feel.
Do I keep my original clutch?: Some T5 kits use the original Jaguar 9.5-inch clutch; the Getrag route typically uses the XJS clutch. Confirm with your kit supplier.