grinding when warm

[I'll sho u]

my 94 mtx grinds on the 1\2 shift but only when warmed up. You can never shift it really fast or it grinds. I reacently changed the trans for almost a identical problem except temp did not make a difference. I am not sure what year trans is in the car now,how do I tell what year it is? What years took what fluid?

 

[CerberuS]

I would try an oil flush of the MTX.

Alot of ppl here found impressive improvement with :

Royal purple ATX fluid