Hey - I have about 95k on my 1999 manual transmission and am trying to figure out if there is any way to determine how many miles I'll have left on it. Right now, everything seems to be catching fine, and I've changed the (dino) fluid relatively regularly (including 10k miles ago).

I guess I'm trying to figure out if it's worth it to go to Redline/Amsoil right now to extend the life of the tranny. I likely wouldn't if I can figure out that I'll only have another 5k before having to replace the clutch/fluid. Thoughts?

As always, thanks for the advice.

... take it to a psycic... or you could drop the tranny and open it up and inspect all the internals... that will give you a good idea of whether it's in good condition
switch to amsoil or redline it's worth it... period... no contest...
if it shifts fine now you might be pleased by results of switching to one of those (personally I liked amsoil better)
http://www.amsoil.com/StoreFront/mtg.aspx

amsoil is the ****. i used their ATF and my tranny's been silky smooth ever since. as far as the lifespan, it's a toss-up. there are people that have logged over 250,000 miles on a stock 5-spd without any problems. some people have replaced it 2-3 times with rebuilt or donors.

don't beat on it too much and it should last you. going with amsoil or redline is well worth it, though. amsoil is rated for up to 60,000 miles, so even though it's a bit more green, theoretically you change it half as often, so it ends up costing less in the long run.