gearchanging issues

Its a 1990, 90 2.5D with an LT77 gearbox. I am having problems changing gears, particularly into 3/4. If I change gears early before I build up speed I usually can change without a grinding noise into 3rd or 4th. Its intermittant in that it doesn't happen every time.

The master cylinder was done about a month ago, its not a clutch disengaging problem, I am certain its something else, however, what?!?

All and any ideas would be great, I would like the best fix asap, also if it does need the gear box out should I do anything else while I'm in there.

I expect I will have to put it into a garage as I don't have the tools to lower the gearbox out or anything like that, mind you maybe I can come up with something, all info much appreciated.

It could be a number of things

The LT77 box is susceptable to low/dirty oil. Try an oils change/topup in the box.

The clutch could be on its way out.

The pressure plate could be weak.

The syncromesh between 3/4 could be on its way out.

Could be that when they did the master cylinder they didn't bleed the system properly or the fluid has gone low.

I have just topped up the gear oil, it took about 1/2 a cup, so don't think it was to low.

I did the master myself and I took some time over making sure it was bled properly, and the master fluid level has not changed so I am fairly certain its not that.

I think it might be a trip into a garage tomorrow.

Sorted it!

The problem was with the master cylinder push rod. The bolts which hold the end of the clutch pedal onto the push rod had slipped down the rod. So when the clutch was depressed it was not engaging on the push rod immediatly, so by the time the clutch was fully depressed the clylinder had only travelled 3/4 of what it should.

I ajusted the bolts on the push rod and now the clutch bites much later than it did, so I am reckoning I am now pulling the clutch apart a whole lot more.

Before, if I had the clutch even a fraction off the floor, it was grinding.

So I think thats that!

Cheers for the help.