Transmissions & Transmission Repair

Tank Cruiser Mark VII A27M, Cromwell IV

Tank Cruiser Mark VII A27M, Cromwell IV
remanufactured transmissions
Image by Nigel_Brown
One of the fastest tanks of the War.

The origins of Cromwell are complicated. They began with an attempt by Morris Motors to design a new Cruiser Tank for the 57mm gun, and ended with Rolls-Royce developing a new V12 engine known as the Meteor (derived from the Spitfire’s Merlin) for use in tanks. Designed in 1942 it took nearly two years to rid the new tank of faults and it was not ready for action until June 1944.

By this time it was, in many respects, two years out of date. Firepower had been improved by the fitting of a 75mm gun but nothing could be done to improve protection and the tank had to rely very much on its speed. In terms of mobility, however, it was excellent. The engine, coupled to a Merritt-Brown transmission, supported on the famous Christie suspension, enabled the tank to maintain high speeds across country or spin around in its own length.

Cromwell tanks were issued to 7th Armoured Division and the reconnaissance regiments of other armoured divisions. In this role they were superb, heading the six-day dash across Europe which freed Antwerp and Brussels at speeds which prevented the Germans from establishing strong defence lines. Cromwells remained in service for some years after the war and a few served with British forces in Korea.

The Cromwell was produced in eight marks in 1943-44. Many (including the Mark IV) were ordered as Liberty engined Centaurs but completed as Cromwells. In turn, remanufacturing earlier Cromwells produced the Cromwell Mark VII and the MarkVIII.

The Tank Museum’s Cromwell is displayed in the markings of the reconnaissance regiment of the 1st Polish Armoured Division, North West Europe, 1944-45.