MINI Cooper Transmission Problems
The MINI 5-speed gearbox GS5-65BH found in the Cooper models (non-S) built between 2001 and July 2004 is commonly referred to as the R65 or ‘Midlands 5-speed’ Gearbox.
The front mounted transverse configuration was a major design challenge when it came to the length of the engine/gearbox unit. In designing the MINI, maximum crash safety and therefore optimum configuration of the longitudinal members in the engine compartment and front body section were priorities. This requirement imposed an additional limit on the permitted length of the engine/gearbox assembly. Because the length of the engine is largely fixed, depending on the spacing between the cylinders, the length restriction on the powertrain as a whole determines the length available for the gearbox.
There was therefore no room in the MINI’s engine compartment for a conventional two-shaft gearbox with all the gears arranged one behind the other. BMW had wanted the car to have a Getrag gearbox, but the original UK engineers put in the R65 gearbox instead, because it was $170/car cheaper, more compact with a two-shaft as opposed to a three-shaft layout, and no inherent cyclic vibrations, so a mass damper was not needed.
The R65 was an existing major component, which was already being manufactured on the Longbridge site, and was in large scale use in other Rover Group front-wheel-drive cars. Originally a PSA (Peugoet-Citroen) design, it was well-proven, and well thought of.
Chris Lee (MINI Product Leader '96-'99) and his team stuck to their convictions, produced rafts of evidence regarding costs, performance and service experience. Back-to-back tests, evaluations on the road and comparisons of torque capacities were all made. In addition, major improvements to the R65's change quality, a reduction of free play and healthy attention to warranty claim records were all needed before Rover’s R65 won the argument.
Although not widespread, there have been numerous reports of failures with the R65 Midlands gearbox over the years. Compounded with MINI USA’s policy to replace instead of repairing these gearboxes with factory rebuilt units, the owners are faced with hefty repair bills from their local MINI service centers.
Fortunately, replacement parts are available for the R65 Midlands gearbox from suppliers such as Mini Mania Inc. www.minimania.com. Qualified independent transmission repair shops are able to repair these gearboxes at a fraction of the cost of replacing the entire gearbox.
Sources: MTZ worldwide 7-8/2002 Volume 63
Motoringfile: The Origins of the MINI Cooper 5-speed Manual, Aug 24, 2003
Occasionally, the Midlands Gearbox suffers from bearing failure on both the input shaft input bearing and secondary shaft pinion bearing, the input bearing failure would give a noise at idle in neutral as well as while driving with the noise reducing as higher gears were selected. The pinion bearing failure gives no noise at idle but an increasing noise in line with road speed as the vehicle increases speed. Both these faults are repairable at minimal expense if caught early; however, if they are left to develop then both can cause a complete gearbox failure.
The other main cause of failure in this gearbox is “planetary gear” failure. The “pinion gears” are located inside the differential and over time they become worn and damaged, leading to a break up of individual gears, this is often not spotted until it is too late and very often results in a complete failure of the gearbox usually with case damage to the diff area. The early signs to look for regarding this fault would be excessive slap or a knock on take up of the clutch bite. Often the first sign of any damage is a noise in the gearbox rather like an ice lolly stick in a bicycle spoke. Unfortunately this normally indicates a gearbox failure beyond repair and would require a replacement gearbox.
MINI Cooper Transmission rebuild Kit.