1965-67 Triumph TR4a Gearbox Conversion Kit 5 Speed Mazda


Prices are exclusive of VAT

Built to order - Despatched 10-15 business days after order receipt
Product code VITTR252




  • Fits exactly in place of your existing TR4a gearbox
  • Improves feel and power delivery
  • Reduces weight
  • Comes fully assembled
  • Gear ratios suit TR4a perfectly
  • Easily fitted by anyone who could fit a standard Triumph TR4a gearbox
  • No drilling or cutting of your classic Triumph
  • Full fitting instructions provided
  • High-quality OE Mazda parts
  • Period correct gear knob 
  • Electrocoated parts
  • Gearbox fitting service available in the UK
  • Worldwide shipping
  • 12-month parts defects warranty
  • Suitable for all Triumphs 1965-67 TR4a
  • In the USA or Canada? Visit our North America distributor Moss Motors


Following on from the success of our gearbox upgrades for MG and Morgan Motor Company cars, we are giving the same treatment to a number of Triumph vehicles. 

Our new range of Triumph gearboxes are based on the same great Mazda MX-5 gearbox as our other creations. And, as with our other gearboxes, each kit is designed specifically for each vehicle, which means no horrible cuts or dodgy welds for you to worry about, just a gearbox that fits perfectly into your TR. 


What’s in the kit?  

  • NEW Mazda MX-5 5 Speed Transmission:
    • Vitesse Gearbox Case
    • Vitesse Bellhousing
    • Vitesse Machined Billet Front Plate
    • Modified rear case with Mazda mechanical Speedo Drive Assembly
  • Mazda MX-5 OE Clutch Friction Plate
  • Bespoke Shift Lever and Shift Knob kept in original position
  • Concentric Slave Cylinder Assembly
  • Braided Clutch Pipe and remote Bleed Pipe for easy bleeding
  • Prop Shaft
  • Spigot Bush with Mazda OE needle roller bearing assembly
  • Speedo Drive Cable
  • Gearbox Rear Mount Bracket Assembly and Isolator
  • Complete UNF fixings kit
  • Clutch Alignment Tool


Can I fit the TR4a gearbox kit myself? 

In short, yes. If you are a confident home mechanic, with the right tools and are comfortable removing and installing a standard Triumph TR4a gearbox you will have no trouble fitting one of our kits, as everything has been specifically designed to match your vehicle.

If, however, your mechanical skill stops short of gearbox installation, we’ve got you covered. At our HQ in Leicestershire, we offer a full fitting service, performed by the team who design and create these brilliant gearboxes.

If Leicestershire is rather too far for you to travel, we can deliver your new gearbox straight to your chosen mechanic anywhere in the world and speak directly to him (or her), should they have any questions regarding the install. 

If you are still unsure, take a look at our installation instructions.


Gearbox reviews and features

With our TR gearboxes being entirely new, as yet we have not had any kits available for media tests. In lieu of specific reviews, we think it worthwhile to share reviews of our very well-received MG gearboxes: 

MG Enthusiast feature

MGCC feature


Shed some lbs: 

The all-alloy case we use in our TR4a gearboxes means significant weight savings can be achieved with this kit.


Gear Ratios: 

The ratios in our Triumph TR4a gearboxes work perfectly, offering a great range of power. Furthermore, the standard gear ratios of the Mazda gearbox are similar to the Ford Type 9 close ratio gear set, which attracts a significant premium over the standard Ford Type 9 gearbox.

Gear Ratio - Mazda Transmission 
1 3.136
2 1.888
3 1.330
4 1.000
5 0.814


Still unsure about upgrading? Ask us anything

We designed this range of gearboxes and work each day to make sure they are as good as they can be. We know them in great details, so if there is anything you need to know, please do not hesitate to contact us. 

Drop us a line on:

Tel: +44 (0)1455 611230

Email: sales@vitesse-ltd.com

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