This is a page about disassembly, repair and reassembly of the Ford (Model B5) FWD gearbox's as used on the Mk1 (4 speed version similar) and Mk2 Fiestas, MK3 and Mk4 Escorts and Orions.

The later (Model IB5) gearbox as used on the MK4 Fiestas and MK5 Escorts is similar but I don't know how similar yet but I'm hoping to get one shortly for the Quantum.

This page is currently only abut 20% finished and will be spilt into subpages later.

This page was last updated on: .

Major disassembly. 

Remove 10 cover bolts. By the way, this is how to tell if your gearbox has a LSD
If the hole is nearly driveshaft size right the way through the diff and you can see a smaller shaft running across inside the hole it's a normal diff.
If you can see a small round hole right the way through like this it's a Ford LSD.
 
Remove reverse switch (left), and the 2 selector detents.
Don't loose the Detent plungers and springs which may fall out.
Undo Torx bolt on 5th gear linkage.
5th gear is this one visible on the top.
 
Remove circlips from input (left) and output (right) shafts. Lift and remove 5th gear assy and selector.
Don't let the syncro springs fall out of the hub, they are a bugger to put back.
 
Remove 5th gears, the input shaft gear normally needs a puller and can sometimes be very difficult to get off even with one.
This one was loose and the splines on the shaft are badly worn so it's a bit knackered.
Remove the 9 Torx screws holding the 5th gear housing on.
 
Removing the 5th gear housing exposes the circlips that hold the input and output shaft bearings in. Move the circlips round so the end of each circlip butts up against the opposite bearing.
  
Push the end of each circlip in the direction of the arrow and catch them when they fly off across the workshop. Circlips removed.
 
Remove the bolts and double ended studs holding the 2 gearbox halves together, the are more around the back, hidden in the picture. Bang all round the edge of the joint with a hide or rubber mallet until the top half comes loose.
Then carefully lever the top up, only lever where there is a gap between the 2 castings, where the arrows are, don't lever anywhere else or you will damage the gasket surfaces.
 
The housing just separated, you might need to tap the bearing through the top of the casing as you lift it. Casing removed.
 
The 1st to 4th gear selector shaft (arrowed) is a tube which fits over the 5th gear selector rod. The 1st to 4th selector shaft is retained by 2 circlips.
 
This is the easiest way to get the circlips off, push on the 2 ends with a pair of pointy pliers. Lift out 1st to 4th selector shaft.
Grab hold of the input shaft, output shaft and selector forks as one assy and lift out.
 
The reverse gear should lift up and the whole gear cluster should come out like this. Lift out the reverse gear and differential assy.
 
This is why this gearbox was making a noise, the usual Ford FWD gearbox failure.
The end of the output shaft is used as the inner for the output shaft roller bearing and the shaft starts breaking up after a while. (left arrow)
Close-up of the end of the output shaft.
The bits of metal flaking off the output shaft get into the other bearings in the gearbox and knacker them as well.
 
The differential bearings have worn so much the diff was rubbing on the gearbox casing. All that's left in the casing is the gear selector mechanism.
  
Remove the shift lock plate (left), 5th gear selector shaft (centre) and selector gate plate (right, you won't have this on earlier boxs). Remove guide shaft and guide lever retaining plate.
  
Remove reverse gear selector.
Undo Torx bolt holding the dog onto the gear change shaft, it's under the oil somewhere.
And remove the gear change shaft and the dog. (this is slightly different on early boxes).
 
These are the various bits of the gear selection mechanism. And these are all the bits so far.
 

 

Input shaft, Output shaft and differential strip down & rebuild.
Remove the input and output shaft large bearings with a puller pulling on the big circlips you removed earlier pushed back into the grooves in the bearings.
Don't forgot to remove the small circlip in front of the output shaft bearing. (I nearly did)
The G clamp helps stop the circlips twisting and the puller slipping off but if your bearings are tight this won't work and will knacker the circlips (but you should be fitting new ones anyway).
The input shaft small bearing normally comes off as shown in the RH picture, just wack the end of the shaft with a copper hammer (If you want to reuse the bearing don't do this but if you want to reuse it don't take it off in the first place.), or use a puller with long legs. (which I haven't got)

Diff bearings.

No picture yet

 

 
Cut through the bearing cages and remove all the rollers.
Remove the plastic speedo gear, the 2 lugs normally break but replace the gear anyway, they are cheap.
On the speedo gear side there's 4 cutouts under the bearing where you can get the normal puller.
But this is how I always have to resort to removing the diff bearing on the other side as there's no room behind it to get a puller.
   
VERY CAREFULLY grind away the side of the bearing until it's wafer thin.
A sharp tap with the hammer normally then cracks the bearing and it can be removed by hand.
This is at the stage where it's just cracked across and can be removed.
Obviously cover all the rest of the diff up to stop grinding dust getting in it.
The cardboard is to stop the vice jaws damaging the gear.
If you need to remove the ring gear undo the 8 bolts but you normally don't need to remove the gear. This is what's inside the outer housing of a Ford LSD.
Closeup of  LSD, I guess the vanes are inside the bottom section.. This is a normal differential. (not a LSD)
Disassembly of the output shaft and other bit's shortly.
   
   
   
   
   

 

 

 Rebuilding the box.
   
This may be a while as the box I striped above is scrap and I only wanted the LSD  
 
Common Gearbox problems
General Note: If you have to replace any gears for whatever reason, you are supposed to replace any gears that mate with that gear as well as they are matched to reduce noise.
This means if you have to replace the output shaft (a common problem) you should also replace the ring gear on the Diff.
If you replace the input shaft (due to the 5th gear splines wearing) you need to replace all the gears 1st to 4th and possible both the 5th gears as well.
However I have replaced an output shaft without changing the ring gear and didn't notice any increase in noise.
Problem. Cause. Remedy.
Noisy gearbox, whining. Disintegration of the end of the output shaft where it's used as a bearing surface.
Your next problem is that the output shaft is about 100 but the bit's from the shaft will almost certainly have damaged all the other bearings in the gearbox so add another 50 odd for a set of new bearings.
Speedo working intermittently or not at all,  if speedo worm gear is replaced, replacement is damaged very quickly. Differential bearings breaking up, cause is normally bit's from the end of the output shaft as above. See above.
Noisy in 5th gear. 5th has come loose on input shaft and worn the splines.  Needs a new input shaft or a lot of Loctite if the wear is minimal. (I once found a box with the 5th gear welded back on !!!!!!)
Difficulty engaging gears. Incorrectly adjusted gear linkage.
Worn syncromesh, worn selector mechanism.
Replace as required but I've never had to do this as these bit's don't seem to wear, or at least they last longer than the output shaft does. :-)
Jumps out of gear. Worn syncromesh, worn selector mechanism. See above.
Driveshafts pop out of gearbox. Worn or missing circlips on the end of the driveshafts. Replace with new or if you must reuse the old ones stretch them before you refit them.
Oil leaks. Worn oil seals. Replace seals as required.