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The Renault UN1 Transaxle Gearbox Guide

posted on 25 June 2026 | posted in Renault Gearboxes

Renault UN1 Gearbox Guide

The Renault UN1 gearbox is a robust 5-speed manual transaxle that has been fitted to a wide range of performance and specialist vehicles since the early 1980s. Well known for its strength, compact design and versatility, the UN1 remains a popular choice for restorations, motorsport and high-performance road cars.

UN1 History

Originally developed by Renault for higher-powered rear-wheel-drive and mid-engine applications, the UN1 gearbox was continually improved throughout its production life with updated gear ratios, synchronisers and internal components. Today it remains one of the most sought-after classic manual transaxles.

Car Applications

The Renault UN1 gearbox has been fitted to many vehicles, including:
  • Renault 5 Turbo
  • Renault 21 Turbo and Quadra
  • Renault 25 V6
  • Alpine GTA and A610
  • DeLorean DMC-12
  • Lotus Esprit
  • GT40 replica cars
  • Various specialist sports cars

Common UN1 Problems

Like most manual gearboxes, the UN1 can suffer from wear as mileage increases. The most common issues include:
  • Worn synchroniser rings
  • Bearing wear
  • Oil leaks
  • Differential wear
  • Selector mechanism wear
Regular oil changes and timely replacement of worn components can significantly extend gearbox life.

Rebuild Parts

Replacement parts for the Renault UN1 gearbox remain available, including synchroniser rings, bearing kits, oil seals, gaskets and other transmission components. As several UN1 variants were produced, it's best to identify your gearbox before ordering parts.

Summary

The Renault UN1 gearbox has earned an excellent reputation for durability and adaptability. Whether fitted to a classic Renault, Lotus Esprit, DeLorean or GT40 replica, a well-maintained UN1 transaxle continues to provide reliable performance and remains one of the most respected manual gearboxes of its time.

SEE PARTS HERE

 

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