Editing RB25 Gearbox - Installation

==Mounting==
The R31 manual box and R33 manual box is identical in length.

[[File:RB25vsRB20.jpg|640px|center|link=]]

An S3 auto crossmember lines up perfectly but the gearbox may hit the top of the transmission tunnel, so you may need to space it downwards. This can done with washers or a couple of M12x1.25 nuts wound onto the studs, then crossmember, and then the standard nuts holding the crossmember on.

[[File:RB25 Box Crossmember.jpg|640px|center|link=]]

==Clutch==
Early boxes are push type. Some of the late R33 S2 RB25 boxes and the R34 boxes were pull type. So you will need a clutch to suit. Make sure you get the slave cylinder with your gearbox as they mount differently. Flywheels are all the same. Push type clutch forks are the same as an RB20 gearbox, pull type forks are different.

===Part Numbers===
* R33 Slave Cylinder: 30620-21U23
* R34 Slave Cylinder: 30620-12U23
* R33 Clutch Fork: 30531-01S00
* R34 Clutch Fork: 30531-12U10
* R33 Release Bearing: 30502-21000
* R34 Release Bearing: 30502-12U00

==Tailshaft==
You just have to get the front yoke on your tailshaft changed to suit the RB25 box. You can get these brand new from Hardy Spicer. Any tailshaft shop should be able to get them. Local and import cars run different sized universal joints so you will need the correct yoke to suit. Imports typically use 27.4mm universal joints, whereas local models typically use 25mm universal joints. Be sure to measure first as this can vary.

===Part Numbers===
* Yoke to suit 27.4mm uni: 21R-3-3738
* Yoke to suit 25mm uni: 2R-3-2938

==Speedo==
An RB20/RB30 speedo sender cannot be used because the RB25 sender is much longer. The gears are also incompatible as the teeth are canted in the wrong direction. You can wire the R33 sender straight to the R31 harness (local only), or you can put a D21 Navara speedo drive in it and screw the R31 speed sender to that. A Navara speedo drive will be perfectly suited if you have 3.7:1 diff gears.

If you use the R33 sender, expect the speedo to be inaccurate as it is suited to 4.11:1 diff gears. You can fit a Pintara gear set, or just use a speedo corrector kit from Jaycar to re-adjust it electronically.

To use the R33 speedo drive on a local R31 just hook the red and black wires from the R31 loom side to the R33 speedo drive. If it does not work, just switch the wires around. Tape off the yellow wire as it is unnecessary.

R31 and R33 speedo drive comparison.

[[File:R33vsR31 Speedo Drive.jpg|640px|center|link=]]

===Part Numbers===
* Navara Speedo Drive: 32702-02G17
* R33 Speedo Sensor: 25010-21U00

==Misc==
The reverse and neutral wiring is the same principle as an RB20 gearbox. The neutral switch is the back one and the reverse switch is the front.

==Contributors==
murph, lysdexia, Sick_R31, crayman, Pablo Rodriguez, AUSBen31

[[Category:Gearbox and Drivetrain]]