My S10 Blazer 4x4 has the original tranny. It has 101k miles on it and runs really well for it's age. Every once in a blue moon it has a hard shift but I attribute that to the way I use the vehicle which is delivering mail part time so I do a LOT of quick start and stops. But other than that occasional hard shift it's smooth as silk.

I'm fixing to do a tranny filter replacement. Should I go with the high mileage fluid? Or just regular? I don't have the original owners manual. Does it take Mercron III? or IV? Is the multi ATF sold under store names such as Advance Auto OK?

I don't need to go cheap but if it's just as good there's no reason not to.

Oh, last question.... what goes in the transfer case?

 

Use the dexron 3. Ive used the multi atf,seems to work fine. Also add a bottle of lucas trans oil. Really helps! Dexron goes in the transfer case too!