I put a post up a few days ago about this problem. I've now found a definite pattern and wondering what your opinions on it are?...
When the car is cold all the gears work fine but as it warms up fully and you start driving, after a few minutes of gently changing gears 1st gear becomes harder and harder to get untill it reaches the point where it really doesn't want to go in.

If the gearbox was going surely you would be loosing 1st,3rd and 5th and still have 2nd and 4th kind of thing? Yet in my case it's only 1st all other gears are fine but the problem gets worse as the car warms up..? There are no unusual noises either.

Suggestions for diagnosing this problem are most welcome.
Cheers!

 

i would guess at clutch related.
try giving it a good bleed first and see if that makes a difference.
i found the fluid on mine had gone **** from the heat off turbo bleeding it made a huge difference to operation

 

So I need to 'bleed the clutch'? Why would it be doing this? Like I say, it goes into gear when the car is stone cold, but as things warm up and you drive it gets virtually impossible to shift into 1st like something is jamming it.

 

I doubt it. Try it, but straws and clutching come to mind. Why would failing clutch fluid select 1st gear as the one it prefers not to work with?? If it was fluid related it would be all gears. Ditto the clutch itself.

Synchro loses it's friction capability as it gets older and once hot it is trying to do something with only a small percentage of its ability left.

It will either be; a bent fork tightening when hot, a failing synchro, or just possibly, a by product of the big nut coming undone and there being slack in the gear set on the shaft where the nut is loose.

I very much doubt that it will be fixable without taking the box out.

David APi

 

Can the forks be replaced without opening the box?

 

Only if you can poke em in through one of the bolt holes.................

David

 

could be a syncro sleve ring not sliding over the hub due to it having small cracks on the hub which expand due to heat and the ring wont slide over the hub. my fith gear hub did this had to press ring off the hub and close inseciton saw cracks two of them from center bearing to the outer part. and its a box out and split and strip i belive to take the forks out

 

That is another possibility, sure. What we usually see is that there is an amount of rounding off, of the synchro dog engagement teethon the sliding part, that juuuuust clear the hub and then when heat takes over, won't pass over as the small clearance has now gone.

I am still of the opinion it needs to come out.

David APi

 

Ok, thanks all for your advice and thanks David - you will be hearing from me soon, I hope you can help.

Cheers

 

Just wondering how you got on with sorting out your gearbox, mines doing exactly the same, it goes into 1st perfectly some times and other times, its stiff to get in and pops in after 1 or 2 seconds. Its only covered 33000 miles and dont abuse it, so any advice would be helpful

 

got the same problemn with mine but it is worst when i go into third it knocks an bangs under my feet an i have been driving sensibly as been running in gonna pop the box out tue an have a look

dave can you pm me prices on 6 speed conversion an ppg or something strong enough for when i up the power to 400/400

 

could be clutch related id give the clutch slave cylinder a bleed and see if makes it better. may not be preasureing up enough and opening quick to get into 1st...

 

Mine usd to do exactly the same, when cold, would go into 1st fine and when hot, would be a pain to get it in. Strangely though, got it mapped at Mocoms and hasnt done it since. I think giving it a good thrashing on the mapping session must have cured it as its going into 1st sweet as a nut now