Kev, in this instance I don't think it's gear noise, but either needle or input shaft bearings.
From the original text I had the noise of severe enough to warrant a call saying the noise was really bad in first, then maybe a hint in second.
When I built the box there was no real history, apart from there's about 100k on it. The build involved a final drive change, diff and output shaft bearing and a set of seals.
Everything 'looked' ok but as you know looks can be deceiving. Even the hint of discouration could be a failing bearing, which might have slipped by.
Having done a few champion ship cars and alot of track cars now running solid mounts on 02a/j/s'sI don't think it's a gear sound. What I've suggested is to change the mount over first. If its quiet, it's the mount, if not, it's the box. I've offered a full strip down to replace the bearings remaining it's just a bit of hassle taking the box out again.
This is the thing with box rebuilds though. I always say I won't do partial builds for this exact reason, especially on unknown boxes. If it makes a noise afterwards it always falls back on the person who built it even when warned this can happen, without fault of the builder. This is only the 2nd time too lol, but I've always honoured my work even if the fault lies elsewhere. Can't say fairer than that :)
---------- Post added at 9:16 PM ---------- Previous post was at 9:15 PM ----------
I will add my own boxwhines like a b1tch, but it is a 6spd quiafe dog box so it's allowed a little bark lol