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Triumph GT6 Overdrive

Our Triumph GT6 overdrive range covers everything the D-type needs: solenoids, seals, gaskets, internal rebuild components and reconditioned exchange units. Exchange units come supplied with less than the solenoid, output flange, adaptor plate and speedo drive, so check what you have before ordering those items that carry over from your old unit.

Before fitting any overdrive, clean your gearbox internally. Old oil cross-contaminating a new or rebuilt unit is the most avoidable cause of failure, and it'll void your warranty. Also note that the washer 538532 must be replaced at the same time to keep your exchange unit warranty valid. It's flagged on the product listing, so don't overlook it.

We've been supplying GT6 parts from our Lincoln warehouse since 1982, despatching to customers in 195 destinations worldwide. For the full drivetrain picture, see our GT6 Gearbox, GT6 Propshaft and GT6 Rear Axle & Differential pages. And if you want more from the car overall, the GT6 Performance Upgrade Parts are worth a look.

Every factory overdrive GT6 left Coventry with a Laycock de Normanville D-type; it's the only overdrive unit Triumph ever fitted to this car. Look after it, and it'll reward you. Leave it to deteriorate, and a rebuild or a reconditioned exchange unit is the answer. Either way, we've got you covered.

Get your overdrive back where it belongs. All the parts you need are right here.

Triumph GT6 Overdrive

Triumph GT6 Gearbox Mountings Overdrive Models

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Triumph GT6 Gearbox and Overdrive Units

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Triumph GT6 Speedo Cable and Drive Pinion - Overdrive Models

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Triumph GT6 Drive Flange and Fittings Overdrive Models

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Triumph GT6 Overdrive and Fittings (D Type) Overdrive and Solenoid

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Triumph GT6 Overdrive and Fittings (D Type) Adaptor Plate - Gaskets and Oil Seal

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Triumph GT6 Overdrive and Fittings (D type) - Output Flange and Fittings

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Frequently Asked Questions

Is the D-type the only overdrive Triumph factory-fitted to the GT6?

It is. The Laycock de Normanville D-type is the sole factory-fitted overdrive on the GT6. The J-type came later, introduced to the 3-rail Spitfire in late 1973 after GT6 production had ended. No GT6 left the factory with a J-type. Retrofitting one is possible, but it needs specific adaptation parts; it's not a straight swap.

Are reconditioned D-type overdrive exchange units available for the GT6?

Yes, reconditioned exchange D-type units are available from our Lincoln warehouse. They're supplied without solenoid, output flange, adaptor plate and speedo drive. You'll carry those over from your old unit. We dispatch to customers in 195 destinations worldwide. See GT6 Gearbox for the matching reconditioned gearbox range.

Can a GT6 D-type overdrive be rebuilt rather than replaced?

Absolutely, it can. Seals, gaskets and internal components are all available individually or as kits. The key risk before any rebuild is oil contamination. Clean the gearbox internally first. Washer 538532 must also be replaced at the same time to protect your warranty on the exchange unit.

Will a Spitfire D-type overdrive fit the GT6 gearbox?

Yes, the D-type used on the 3-rail Spitfire and the GT6 is the same unit, so they're interchangeable. That said, gear ratios differ between the two cars, so check your GT6 Propshaft and full drivetrain spec before sourcing a used unit from a Spitfire donor.