How to modify your MA5 Gearbox - 5th gear change
To lower the revs in 5th, read as: Increase speed on tuned engine / more
fuel economical (but less acceleration!)
You can find the MA5 gearbox on a lot of Peugeots and Citroens. The MA5
gearbox is normally used on the TU series engines: the 954cc TU9, the
1124cc TU1, the 1360cc TU3 and the 1587cc TU5 8valve and 16v.
5th gear options:
All the available end reductions for the MA5 gearbox:
Together with the standard 2CA63 end reduction (16/65) you will run 3625rpm
instead of 4035 rpm with 155/70/13 tires for 120kmh. Maximum speed is:
205 km/h@6200rpm (but you will need about 98Kw 131hp at the wheels! ).
This is the 2CA63 gearbox, that came with my TU3 engine. It has
the following gear ratio's:
1st: 12/41 3,41667
2nd: 20/39 1,95000
3rd: 28/38 1,35714
4th: 37/39 1,05405
5th 41/35 0,85366
There are three options for the fifth gear:
I replaced the original 5th gear for an 43:33 ratio. Which came of
an 2CA86 gearbox.
If you look closely, you 'll see the
41 count gear on the bottom.
||First remove the fifth gear cover, after that remove the locking
pin for 5th gear.
||Select Reverse gear, and carefully press the 5th gear fork down.
You have now selected two gears, so you can remove the nut on the
||I removed the fork, but you will have to be carefull! Hold the centre
sention firmly in place. Otherwise you will have to find 3 little
springs and three little balls in your shed!
||Hold the remaining stuff together, gently pull it of the axle. Put
a screwdriver on the bottom, so you can also take the bearing off.
||Remove the retaining clip and ring. You will have to remove the
gear with a pulley remover. You can also use a flat screwdriver: gently
put it under the gear and wiggle. Turn 120degrees, wiggle again...
Keep repeating that a thousand times and you will get it off eventually!
||This is how it looks when the gears are removed. Mounting them is
the reversal of taking them apart! But do not forget to install your
General advice: Drain the gearbox oil before you begin. Otherwise your
shed will be like an oil platform! Remove the drain plug (just below the
differential) with a square socket wrench and drain the oil, and at the
same time remove the metal parts that are collected on the magnet attached
to the oil drain plug.
There is also an "fill" plug or "level" plug on the
gearbox, just next to the fifth gear cover. If you look at the top picture
you can see them both. This plug has also an magnet and needs to be cleaned
once in a while. Fill the gearbox with 2 liters of SAE 75W80 oil.
How to Lower you Citroen AX or
Tuning the Exhaust Manifold of a TU-Series Engine
Dashboard connectors Citroen AX
List of MA4 & MA5 gearbox ratios