Need a bit of advice please.
I had my clutch and flywheel changed in february because the master cylinder was leaking and I was losing clutch pressure. The DMF was changed vauxhalls did a naff job of fitting a new one about 6 months previously. All seemed great for about two weeks after the new clutch went in etc and then i started to notice 1st to 2nd was getting tight. The then went through to 3rd as well as the problems seemed to get getting worse.I checked under the car 3 months later as I thought at first it might be to do with the wrong gearbox oil or somthing silly like that. Anyway after checking I can see that the leak is coming from the bottom of the Gearbox where it bolts onto the engine. my dad thinks that it is the gearbox oil seal inside the box. In the four months since the clutch has been changed it has lost 0.4l of Gearbox oil(toped it up at the weekend), but that should not account for the nothcy gear change. Adding the lost GB oil back in didn't get rid of the nochy change either.
before the clutch change I never had a notchy box or any kind of issues changing gear. Do you think that perhaps the clutch does not have enough clearance(change is easier the further up the box I go). If I double clutch between gears it can be a smoother change. Could the oil leak inside the box be causing this issue as it leaks on the flywheel and clutch?
Sorry for all the questions, but it does seem very strange for my car to develop this problem only 2 weeks after the clutch was changed. Mechanic who did the job is saying that it isn't anything to do with him and that it must be a new fault, but I do not agree. we have settled for him to strip the box and check where the fault is coming from(got to pay him £175 again) in the next couple of weeks for, but it would help me if i had a better understanding of what could be causing this fault so he doesn't fob me off again.
my vehicle is the '05' plate Vectra C 1.9cdti 120bhp 8v (6speed box)