Gear change is super stiff!

Hiya,
Had an 085 8p box with a few dodgy bearings and leaky seals. Stripped it right down and replaced all the tapered roller bearings, oil seals and the 5th gear needle bearing as it had collapsed. Hadn't run this box in the car previously, so history is unknown.

Filled the box with ~3.2l of fully synthetic oil (couldn't get the level plug out). The box feels fine when cold, apart from its slightly hard to find 1st and 2nd due to the shift gate being too narrow. However when warmed up, especially after a long motorway stretch, all gears are very hard to find and the linkage is very stiff. I had no issues with the 4 speed that was in previously.
5th gear also gives a small crunch when engaging and pops out, but presumed this would be down to adjustment.

So as the shifting was fine previously I have narrowed it down to the shifting within the box. The cup that fits over the ball on the internal shift rod is adjustable, and I was wondering if mis adjustment on this could be causing the issue, as apart from that I cannot see what the issue could be!

Any thoughts, or maybe a correct way of setting up the internal shaft? I don't want to remove, adjust and reinstall the box only to find that it made no difference! But would like to keep the 8p, as the first 4 gears feel very similar to the old box, and the 5th is a nice overdrive to quieten her down on the motorway a bit!!

Cheers

have a look on the clubpolo forums, theres a howto post somewhere on adjusting the 5th gear selector correctly, this may help with the rest of the gear selection issues

Cheers, got the box out now, gunna have a little poke about to see if theres anything obvious. 5th is on a separate shifter fork to the rest of the box so I'd presume any adjustment to that purely affects 5th.

If I cant see anything I guess I'll just throw the 4 speed back in…