Is it bad to use shockproof heavy in a gearbox?

[someonestolecc]

I have a s13 gearbox but since they're mostly the same as rb20 gearbox I thought I'd ask you lads.

I recently changed my oil but upon draining it went to my 'box-o-oils' and found I hadn't bought the 3 bottles of shockproof light as I thought I had and only had 2 bottles of shockproof heavy.

I put it in and the gearbox feels better now and I intend to put another 400-500ml in (it wasn't quite up to the top plug-hole) shortly.

My situation is the gearbox is recommend "AP1 GL-4" and as far as I can tell the lubricants/oils that come in that spec are rated at the same viscousity as the redline heavy shockproof stuff is 'equivalent' to.

The question inevitably becomes - does anyone here run shockproof heavy in their gearbox and would it be bad? Should I be draining this and putting in mt-90 or something?

Thanks.