for an old transmission with a dirty valve body, yes
what did the pan look like when it was serviced, fluid clean and red or brownish with a lot of black sludge in the bottom?
a valve body rebuild kit/shift kit is about $30 and comes with detailed instructions
clean it in mineral spirits and re-assemble
what is the mileage?
I have used these before for AOD and had goo results, they were recommended by the losal transmission shop
btw, they have VERY detailed instructions along with comments, enjoyed the sometimes scarastic answers/statements Rebuilt Transmissions Transmission Parts (transgo is company name)
sometimes it doesnt like to go untill its warmed up is that normal
Yes it is normal when the seals are dried out. The old tranny guys call it "morning sickness". I have an 86 F250 4x4 C-6 that has been like that for over two years now. Although it shifts good & there is no other problems. What I did that helped get it through the last two years was add a can of TransX. That helps the seals. But this is not a cure. I'm rebuilding mine this spring.
As for fluild as stated above DEXRON II now DEXRON III is what is called for. But if you were not having issues before changing the fluild & you installed Type F hard shifting is normal because of the friction modifiers in Type F. As a rule if I remember correctly if you added Dexron to a type F trans it would be mushy shifting.
I would go to Walmart & buy a can of TransX like $5.79 were the parts houses want $9. See what happens. TransX will not hurt anything. It has been around since I was a teenager in the early 60s. We used it then.
The other option if you have the wrong fluid is to add a can of LubeGard it is a friction modifier.
Hope is helps.