How do I check condition of E58 gearbox

[PrettyCoolWagon]

Hi guys, I've got an E58 factory viscous LSD gearbox, thinking of fitting it up to AW11 bigport GZE and 4wd transfer case from E57F5 box. (without the LSD)
Going into 4wd corolla wagon.

How do I check the health of the gearbox?

Last thing I want to do is, put the box and engine in only to find out it's stuffed or got a problem that just gonna get worse over time..

As far as I can tell the engine it came with was a JDM AE101.
When I bought it recently, after it was pulled from an aussie AE92 hatch. It'd had some work done to it, ..bores had been cross hatched and ports were machine matched. It'd been converted to turbo and had new looking gaskets all over ...including a blown head gasket!

So chances are good that it copped a thrashing at some point.

What sort of things am I looking for?
Any tips on how to take the gearbox apart or what to be careful of, photo's would be great!

Thanks.
Jed

[PrettyCoolWagon]

bump
trying to get this baby on the road before club cruise in mid May..
Any info or pics on what worn synchro's look like for example??

Might practice on a gear box I know is stuffed already..