Gearbox rebuild

[richandhazel]

Some of you may remember a while back (before I had the problem with my Audi driveshaft coupling snapping) I was talking about dismantling my worst (and completely knackered) Mk1 gearbox and seeing how easy/difficult it is to fix DIY.
As its a miserable day and I have finally cleared out the garage I have decided to give it a go.
Pictures and details to follow...........

[golfvr6]

Yep i remember, keep us posted  

[richandhazel]

Going OK so far. All the 5th gear assy is now removed. I now need to buy some more spline drive bits as I only have 8 and 12mm and it appears I now need a 5mm one!

[golfvr6]

How do separate the gearbox housing from the diff/clutch housing? couldn't get my one apart  :'(

[richandhazel]

I'll let you know how I get on............haven't got that far yet.

[richandhazel]

Bought a complete spline set this morning.
Housings are now seperated. It was no problem at all. I looked at the special VW puller and made one out of some steel box section I had kicking around..........I'll post all the info and pics soon.
Have now removed the selector forks and am moving onto removing the gears and mainshaft etc.
I'm enjoying this, not nearly as difficult as I was expecting...........so far.

How do separate the gearbox housing from the diff/clutch housing? couldn't get my one apart  :'(

[golfvr6]

I removed all the bolts on mine , but the 2 section won't separate  

[richandhazel]

Once I got the puller on, I wound it in a little and simply tapped all round the housing joint with non metallic hammer.........just popped apart. Maybe I got lucky  

[golfvr6]

Do you have to remove the input shaft bearing to get the cases apart, or just undo all the bolts around the outside or the gearbox section  

[richandhazel]

There is a clamping plate that holds the mainshaft bearing in position. (Item 14 page 152 of the Haynes manual 726, the brown one). That was what I needed the m6 12 point spline drive for last night. Undo the 4 screws (item 10) and then all the bolts around the outside of the gearbox casing.

Mine is now completely dissassembled and I now know what has happened to the gearbox. The pinion shaft lower bearing has broken up and parts of the bearing have found their way between the diff and the lower pinion diff drive causing major damage to both. Parts of the bearing have also found their way into the 5th gear assy and caused major damage to that.
Photo's and a full write up to follow..........for anyone thats interested.