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Gearboxes
Created: February 06, 2014
Evo (Trannex) 1950s design with 1990s engineering and technology - originally done by the inimitable Davc Hirons at Trannex, now under the EVO banner at Mini Spares Centre following their buy-out of all the Mini/Sprite Trannex products some years back now. The only real similarity to the old Sali...
How do I know which transmission my Classic Mini has?
Created: January 20, 2014
It’s really quite easy to tell which generation of gearbox, shift linkage, and axles your Mini has. Let’s say you want to order a replacement but terms like “remote”, “rod-change”, or “pot-joints” have you a little befuddled about just what the heck to order! Let’s very simply describe the three styles of transmissions and axles used in the production of the Classic Mini.
Classic Mini Cooper Gearbox - Common sources of problems
Created: October 28, 2002
A gearbox needs careful and proper attention when building it up. It's the knowledge of what to look for prior to and during the build that sets the 'professional' builders apart.
ENGINE TRANSPLANTS - gearbox information
Created: November 01, 2000
Selecting the right final drive ration is a subject worthy of an entire book to explain the whys and wherefores, and also causes much consternation on the part of the transplanter. Much confusion’s spread over which gearbox has the best ratios, is best to use, and with which FD. For a detailed account on this and covering all gearboxes fitted as standard to the Mini, see the relevant separate articles 'Gearbox - Standard production gearbox types'.
Created: October 31, 2000
The standard drop gears are fine for practically all road use - almost irrespective of power output. Despite what many folk believe - they are more than strong enough, and will perform perfectly well if correctly set up. That means getting the idler and primary gear end floats right, and using new bearings for the idler gear at each re-build.
Created: October 30, 2000
Elsewhere we've considered what alternative standard production ratios are available - but that still leaves you with the power-consuming and limited-ratio alternatives helical tooth type gears. Not desirable in a competition orientated car. The solution to this comes in the form of several types of straight-cut gear sets
Created: October 30, 2000
The standard diff unit’s componentry falls well short in the performance stakes. As an absolute minimum you should fit an up-rated diff-pin - whether this is because your racing regs don’t allow alternatives, or merely for the road - along with new planet-wheels and thrust washers.
Created: October 26, 2000
The final drive gears are ultimately responsible for the way your Mini goes after engine, gearbox, and under carriage tweaking has been applied. The aforementioned and the degree to which it has been done will affect the decision as to what Final Drive is required. They’re also responsible for much discussion between many tuning freaks, and confusion to the less informed.
GEARBOX - How they work
Created: October 25, 2000
Having decided on or even implemented a course of action to bolster the performance of your Mini’s engine, maximising it’s potential should encompass a good look at the gearbox. It rarely does, as most folk take one look at those seemingly formidable teeth and decide it's not for them and stay well clear.
Synchromesh Transmissions vs Dog engagement
Created: April 25, 2014
Dog engagement is typically limited to racing applications where fast, precise shifting is needed. Dog gear engagement works by having numerous large teeth or ‘dogs’ that mate into matching openings machined into the opposite surface of the drive gear. Unlike the synchro engagement, there is no synchronizing mechanism to assist in equalizing speed.
ENIGINE TRANSPLANTS - Changing FDs and speedo drive ratios
Created: November 02, 2000
If you’ve decided the FD fitted isn’t what you want, changing the FD is possible without separating the engine from the gearbox. Removing the diff case will allow you access to the diff assembly to change the crown-wheel, and access to the gear-change linkage.
How To Articles
Review of the Best-Designed Classic Mini Shifter
Created: November 18, 2019
Review of the Best-Designed Classic Mini Shifter; what makes KAD worth it?
Classic Mini Automatic to Manual Gearbox Swap
Created: July 05, 2018
Here we go through the steps to convert a MkI Mini Van from an automatic gearbox to a manual gearbox. The Classic Mini Coopers with automatic transmissions have unique engine blocks - you can't just swap out the blocks from one to the other - the whole power unit must go and be replaced with a manual block and transmission.
How-To Rebuild a Classic Mini Cooper Remote Gearbox
Created: September 06, 2016
VIDEO: How-To Rebuild a Classic Mini Cooper Remote Gearbox
Classic Mini Rod Change Gearbox Rebuild - Mini Mania Video
Created: March 11, 2011
Classic Mini Gearbox Rebuild - Part 1 Gearboxes may seem complicated but they are very simple in their construction, and surprisingly easy to put together. The main issues are having the right tools to do the job.
Created: June 19, 2008
Gear Box Rebuild Written By GuessWorks Gearboxes may seem complicated but they are very simple in their construction, and surprisingly easy to put together. The main issues are having the right tools to do the job. So here's a list of what you will need. SEE VIDEO HERE Torque Wrench with a...
Classic Mini Idler gear - Setting end float
Created: December 04, 2001
A fairly crucial part of how the idler gear operates is its tolerances and running clearances. End float is a continual problem as folk often ignore it, and because many units left Rover with incorrect (usually too big) clearances.
ENGINE TRANSPLANTS - Engine to gearbox fitment
Created: November 01, 2000
Assembling the engine to gearbox (transmission) is explained and simplified in this article. Contrary to popular mis-guidance, all BBUs will fit all four-syncro gearboxes. It was only the three-syncro boxes that varied in casting dimensions causing hassles where 1275s were applied to 850/998 gearbox casings. The longer throw and bigger crank and rod assembly dimensions fouled the sculpted areas in the gearbox case,
Austin Mini Cooper Close-Ratio Conversion A+
Created: October 26, 2000
As outlined in the 'Gearbox - standard production gearbox types' article, it is entirely possible to change the common 4-syncro gearboxes to the helical close-ratio set-up as used in the Cooper S, 1275GT, 1300GT, and some early MG Metros providing the right parts can be sourced. And you don't already un-knowingly have the close-ratio kit fitted! Part numbers are detailed at the end.
Classic Mini Cooper Gearbox - Close-Ratio Conversion Pre-A+
Created: October 26, 2000
It is entirely possible to change the common 4-syncro gearboxes to the helical close-ratio set-up as used in the Cooper S, 1275GT, 1300GT, and some early MG Metros providing the right parts can be sourced.
Limited Slip Differential
Created: October 17, 2000
‘Salisbury’ is the word banded about by most un-enlightened folk when discussing LSDs for Minis, mistakenly believing the word covers all Mini orientated LSDs. This is grossly incorrect. The ‘Salisbury’ was designed in the ‘50s at a time when racecars were a good deal less sophisticated than today. Tyres were usually cross-ply with severely limited grip due to poor compounds developed ostensibly for rear-wheel-drive cars; the front wheel drive of the Mini being a rarity.
Austin Mini Cooper Limited Slip Diffs, What they're about.
Created: October 16, 2000
Modified engines producing more power generally induce owners to drive with greater verve, particularly when competing in one of the many motorsport disciplines. In fact this isn’t isolated to modified Minis. Owners of relatively standard machinery competing in a discipline or merely out on a country lane blast are subject to the same determination.
Austin Mini Cooper Limited Slip Diffs; parts for installation.
Created: October 16, 2000
Fitting an LSD isn't as simple as replacing the diff cage unit. In all cases a certain degree of diff housing modifications is needed - material needing to be ground/filed away to provide clearance for larger diff housing cases and crown wheel bolts. Although it has to be said the Quaife diff is supposed to fit without these mods. I've never found that.
Created: January 30, 2000
Mini Mania is the sole US representative of the excellent "Tran-X Limited Slip" differential. Basically a clutch type diff, it is a 1950's ideal incorporating a 1990's technology. It is much more refined than the previous plate type diffs.