trans fluid

has anyone found a better than average transmission fluid to use, i just got my trans back from getting it rebuilt and thought i would ask about whats the best to use, i know they come up with better oils to use in the engine in the past 50 years, just want to get the most life out of it, thanks for any help, john

John i don't have a good answer for that BUT i'd call the person who built it. that way you keep the warranty... let us know what he says...

yeah i should have asked him, i'll call tomorrow and see what he says, hes old school i dont know what he'll say,

The only ATF you can buy these cays is new formula!

ATF is designed to
lubricate and cool the components
Transmit the power thru hydraulic action
Keep the components clean by additives eating deposits and flushing dirt and clutch debris to the pan
Not to foam, which would hamper it's cooling and power transmitting abilities

The differences between the different formulas are
Different clutch material compatibility
Different friction slip amounts

Way back, it was Dextron (GM/Mopar) or Type F (Ford).
Type F was the old school "firm shift" cheap upgrade.
It also worked with GM/Mopar clutch materials, but Dextron did NOT work with Ford clutch materials. Putting a quart of Dextron in a Ford trans meant slipping to failure in short order.

Since the choice is now Mercon/Dextron (GM/Ford) or ATF+4 (synthetic Mopar), I'd also check with the builder. I'd guess that almost all aftermarket rebuild kits include clutch materials that will work with any fluid, it is simply a matter of which has the friction desired. Talk to your builder!
Also, make sure the lines and cooler(s) are flushed properly. Usually a can of pressurized stuff at the parts store is required. Again, ask your builder!

Also ask how they want it installed and started.
I'd suggest pouring a quart or two into the converter before it's installed, and starting it and running in Neutral, NOT Park to check/fill the fluid.
The pump operates only in gear or neutral, not in park.

I don't suggest any additives, ask your builder!
There are HP hi-dollar fluids (Redline, Amsoil), again, ask!

Make sure to follow any builder's suggestions and document them as much as you can. Make sure the shifter and throttle pressure (kickdown) are adjusted properly. Both can also burn up a trans if not right!

thanks rod, i'll ask him tomorrow, he did say add a qt. to the convertor before installing it then 8 qts, to the trany, and run it through the gears and check it in neutrel

I believe most of the performance minded (especially drag race) TF trans builders/shops recommend type F as Rod mentioned. Any would be fine in a typical street application. I use F in my van after I rebuilt it. There might be a difference in service life of the clutches between F and Dex, if I remember correctly F would yield slightly shorter friction material life?

GM=Dextron =Does !! offer better life to all! Ford fluid is best for crisper shifts! Ive used both =yet i always add a shift improver kit to all my trannys & run GM fluids.even in my ford cars. Have yet in total life to have a trans go bad!!