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Changing 4 speed for 5
myke pocock - 29/7/09 at 11:20 AM

What is involved in fitting a Sierra 5 speed box in place of a 4 speed onto a Ford X flow engine? Do I need a different prop shaft as well?


blakep82 - 29/7/09 at 11:23 AM

i think the only think needing changed is the gearbox mounting point. i think the 4 speed mount is about 2-3" further forward. the actual physical size of the gearbox is the same i'm told so you shouldn't need a new prop


will121 - 29/7/09 at 11:25 AM

think its new prop as gearbox longer, check clearance as bell housing its fatter to and other problem i had was speedo take off hit chasis rail


prawnabie - 29/7/09 at 11:27 AM

Im doing this very conversion now mike!


blakep82 - 29/7/09 at 11:27 AM

quote:
Originally posted by will121
think its new prop as gearbox longer, check clearance as bell housing its fatter to and other problem i had was speedo take off hit chasis rail


the gearbox is longer, but the tail housing is shorter on the 5 speed


britishtrident - 29/7/09 at 11:41 AM

An awful lot depends which exact type 4 speed was fitted.

The M2 Escort box is a lot smaller than the type 9 ---- everything is either bigger or in a diffeent position


will121 - 29/7/09 at 11:42 AM

quote:
Originally posted by blakep82
quote:
Originally posted by will121
think its new prop as gearbox longer, check clearance as bell housing its fatter to and other problem i had was speedo take off hit chasis rail


the gearbox is longer, but the tail housing is shorter on the 5 speed


just thinking why i changed my Prop at the same time and now think it was the output shaft on the 5speed has a different amount of splines to the 4 speed hence wont fit will at least need a modification, also i changed clutch.


blakep82 - 29/7/09 at 11:45 AM

oh, yeah... i'm just thinking of the rocket box. others will be different.


prawnabie - 29/7/09 at 12:03 PM

You will need a clutch plate off a 1600 cortina (190mm not 215mm) with a 23 spline inner. The cover and bearing from the old clutch can be re-used.

The gearbox is about 4-5 inches longer so the gearstick will come out in a different plance and the rear mounting will need moving back to. The mounting off the 4 speed box will fit, but might be a little worse for wear - I recommend the westfield part for this.

Duse to the increase length of the box, the propshaft will need to be shorter. Not only this but the sliding joint on the gearbox end of the propshaft is different on the 5 speed. You will need the front joint off a capri or rs2000 (not sierra due to it being a rubber joint). I would recommend getting a new prop made though.

After all that, the gearbox itself is alot bigger and heavier! Especially in the casing after the main gear "box" - it hangs down quite alot.

A couple of titps - make sure you get the right clutch arm for the box and make sure the box is from a 2.0 not a V6!


britishtrident - 29/7/09 at 03:00 PM

The british Cortina boxes have the mounts in the same position and is the same length as the type 9 ---- pretty sure the same goes for the German made Cortina heavy duty 4 speed box.
Not sure about the splines .


rusty nuts - 29/7/09 at 06:11 PM

Early1600 Sierra clutch is the one to use as you don't need to mix and match