www.imoc.co.uk

---

UPDATE: after 100 or so miles cruising in 5th it has now started to pop out again. This means that it is essential to change/renew 5th gear itself in order to cure the problem. This can still be done with the gearbox in situ, but a puller would be needed to remove 5th gear.

MORE updateage. After it popping out a couple of times it hasn't done it again since. So all seems to be well. Have since done 5000miles with no probs

5th gear pop-out on a MK1 NA is one of those things that just about every MK1 owner will experience at some point. Basically you put it into fifth and either when trying to accelerate or lifting off the car will pop-out of fifth gear leaving you with neutral and a screaming engine! Obviously it becomes pretty annoying pretty quickly. You can hold it in gear by resting your hand lightly on the gearstick and holding it in, but this gets tiring on a long drive. Basically the hub and fifth gear wear on the teeth in which they engage. Over time you can tell if this is something you are going to see because the gearstick will 'nod' as you accelerate or more commonly when you lift off. As the wear increases it gets to the point of where it will knock itself out of gear.

Its up to you how far you want to go with this as i changed the fork and hub, but really for a totally as good as new permanent solution 5th gear will need changing too. This would involve a puller and obviously the expense of buying 5th gear. For the cheapest repair you could get away with just buying the hub and fork (the hub is a superceded part so the fork has to be bought to match it). I would say though that this repair ought to last a good 20K miles or so. Time will tell i guess. But for an easy DIY repair that requires only basic 'beard' skills its hard to beat.

With the car supported on axle stands and the nearside rear wheel removed you can start.

Firstly you need to drain the gear oil from the box. This is relatively straightforward and requires a 24mm socket for both the drain and fill points. A breaker bar may be needed as these tend to be tight. A tip is to crack undone the fill point first because if you can't get this undone you'll never re-fill the oil again! Then catch the gear oil (if you haven't changed it in the last 15K miles i'd go for putting new oil in when you come to refill it. I re-used mine as i only put it in 5000miles ago.

Then you need to work on taking the end casing of the gearbox off:

This requires an extended 12mm socket for all the bolts bar one which will need a 12mm ring spanner, its the one right by the gearbox/chassis mount in a 1 o'clock position.

These are all relatively easy to undo tbh. Once they crack off you can undo them all very easily with just the socket.

Once all are removed you will need to tap the casing lightly with a hammer just to loosen it. There are a couple of lugs that stick out at the bottom of the casing and one up the cabin bulkhead side that can help you here. We ended up putting a screwdriver down the boot bulkhead side and variously wiggling the cover until it fell off and landed under the car! Still no harm done and it was off pretty quickly.

Now you have the cover off you can see 5th gear:

With a 10mm socket you can undo the nut that retains the selector fork in position. Once this undone slide the fork and hub off 5th gear until it comes off in your hand, it will kind of click as it comes off, but won't require any force as such.

Here is the old fork and hub


Now for the shiny bits:
Fork

Hub


Installing the new fork and hub really is very straightforward. You need to put them on together with the fork sitting inside the hub. I smeared a little gear oil around the two mating surfaces. You will need to spin the hub around until it locates properly on the outer dog teeth of 5th gear. It will be obvious when you have it right as it will slide on very easily:


Then its simply a matter of doing up the fork retaining nut and putting the casing back on. I used red hermetite to seal the cover. It looked like a simple paste type gasket had been used originally and this worked perfectly well. I just gave the casing a good clean applied the hermetite and stuck it on. NB there are two locating dowels for the cover.

Then having replaced the drain plug for the box you can re-fill then put the filler plug on and thats it.

Test drive i did revealed that 5th gear no longer popped out, though there was a slight amount of nodding of the gearstick when lifting off, this is due to the existing wear on 5th gear, though the new hub is enough to stop it popping out.

Here is a pic of the wear on the dog teeth of 5th gear.


Time taken by me to do this job 1.5hours. I would honestly say it should not take anyone more than a couple of hours even if they are relatively new to bearding.[/b]