5 SPEED CLOSE RATIO HELICAL GEARBOX WITH ATB 3.9FD
MSG03-39ATB

£4,057.08 exc vat

£4,868.50 inc vat

Special orderSpecial order
New for 2023, special heavy duty 2nd and 3rd gears with laygear and 1st motion to match giving a quiet road box suitable for engines producing upto 125lbft of torque on naturally aspirated engines.



Ratios are:



1s...

£4,057.08 exc vat

£4,868.50 inc vat

Special orderSpecial order

Recommended usage 1 x MSG03-39ATB to fit one mini.

Kit contained products

A plus mainshaft. 18mm (11/16")nose bearing type.

The earlier mainshaft pre A plus is22G833

This shaft uses DAM7485

Special locking washer for 3rd gear on 4 synchro gearboxes plus our own 5 speed 5th gear. The washer for 2nd gear is 22G839

Only for the 4 synchromesh gearbox synchroniser gear hub. There are 3 of these per hub with BLS107 ball bearing.

Minispares recommend this central oil pick-up be installed with every transmission rebuild.

The original Mini oil pick-up pipe lives in the right hand edge of the gearbox casing, which is okay if you are driving straight. But during a right ...

This o ring goes on the detent plunger located behind the gearbox output shaft side plates on all Rod change gearboxes. See also BLS110 ball & 22G2083 spring. Also fit BAU5043 heater matrix.

The favourite final drive for minis this is the pre A plus type which was stronger and fitted to Cooper S etc. goes with 22A411 crownwheel.

The longer one piece bush as fitted to all late reverse gears. Early type had 2 single bushes which sometimes came adrift after arduous use.

19 tooth pinion for 3.1 and 3.2 final drives with 3 groove mark

list below for other markings

17 teeth central groove

18 teeth offset groove to one edge

19 teeth 3 groove markss

All differential crownwheels used these locktabs. 3 required and if you need new bolts see ATA7043 (6 of.) All sold singly

When you take the side cover off the differential housing on a rod change type gearbox this detent ball spring sits on a ball bearing BLS110 and the sleeve is 22G1870. The oil seal for this is 22G1417.

Genuine RHP bearings. Not cheap Imported rubbish as sold under this part number.

This is the workhorse of the Mini gearbox. This double roller bearing supports the shaft where it transmits the power to the wheels. When this bearing goes, the...

Drive shaft oil seal or diff output shaft oil seal for all Mini's except Cooper S and early Automatics. 2 required per gearbox.

Upgraded version in Viton available us ADU5738VITON

You will need to shim up your diff bearings with these washers as required. See workshop manuals for details. See also DAM3109 & DAM3633.

Try these GENUINE MINISPARES superseal gearbox output shaft gaskets specially made to try and eliminate leaks.

Sold singly,2 per gearbox

Torrington/Koyo idler gear bearing with special rollers for allowing movement on late type idler gears. The idler gears for twin point cars were also made from clean steel as an upgrade from 1996 on. This special bearing replaces the cheaper inferior...

The upper differential housing gasket for all minis. The lower gasket for rod change gearboxes is 22G1836 and for remote use 2A3506B.

Often overlooked when doing gearbox rebuilds this seal is very important as it sits in the very bottom of the case and is the source of irritating oil leaks.

The large round metal plug in the bottom of the gearbox is the pivot pin for all th...

for the inspection plate on the front cover of the transmission where the speed cable goes to -it has 2 bolt holes cut out

Inside your gearbox synchro hubs are 3 springs and these ball bearings to lock it in and out of gear. Often pop out and get lost when splitting the inner and outer hub.

Gearbox oil strainer to gearbox internal case gasket and also used on the C-AHT54 special oil pick up pipe. One also sits on the outer plate held onto the gearbox outer casing by 2 screws.

Lower differential housing paper gasket for old magic wand and remote type gearboxes, rod change gearboxes.

Every 4 synchro gearbox had a straight cut first gear as standard.

This one has 31 teeth and beware complete straight cut race gears sets use a 29 different tooth count.

Genuine RHP as originally fitted to every production Mini.

Two of these main diff carrying bearings are required in the gearbox and this new steel caged type fits either way round. Should be pre loaded by 1-2 thou.

Some original fi...

Mini Spares Performance Baulk ring.

The standard sintered baulk (synchro) rings are not tough enough for the demands of performance useage, in many instances lasting only one race before failure or breakage. The main reason is the incompat...

Genuine 1ST Motion shaft SINGLE track original bearing for 4 synchromesh 1st motion shaft.

This is a Genuine RHP bearing, and should not be confused with cheap alternatives. The cheap aftermarket bearings often fail and the work involved to...

Minispares were the first company to produce these layshafts for performance engine/gearboxes as the standard type would flex and resullt in the breakage of the bearings causing seizure. Produced in an upgraded material and heat treated to the correc...

The Swiftune classic Mini Quaife ATB Automatic Torque Biasing differential offers the benefits of an LSD limited slip differential but saving you money on crownwheels and pinion plus output shafts!!

The Swiftune Quaife ATB avoids the need fo...