Using Synchromesh Tranny Fluid

[jtl]

I've read here and there about using Synchromesh fluid to quiet down a tranny where the synchromesh's grind a bit. The reading I've done about it seems to say that it is a straight replacement for the stock fluid while some of the posts here are saying they only use 1/3 synchromesh and then 2/3 stock fluid.

Is there any harm in doing a straight replacement or is it better to mix the two. I have a 91 na.

[aosmith]

you could do harm by using an improper mix, it could not stick to gears as well it should cause some parts not to be oiled as well, it also may not provide a proper amount of lubrication