Transmission Fluid

I have a TH400 3spd mated to my Pontiac 400 in a 1969 GTO and was wondering if anyone could recommend what type of trans fluid to use, before I just put the advance auto parts brand type F in.  I’m curious if it’s worth the double price per quart for royal purple?  Also, how many quarts do these things hold?  I’ve heard 14 quarts, at 13 dollars a quart for RP that’s $182.00 so, I want to get it right.  

I just rebuilt my TH350 for my 79 Trans Am. I used the advance brand tranny fluid on it but I do add Lucas brand products to my vehicles they have an additive for almost everything out there mechanical. Engine oil, Tranny, and Power steering. Also Diesel and Marine products. Seen this stuff do exactly what it says it does. As far as the Royal Purple don't see any more benefit. As long as fluids clean and cool shouldn't have any problems. The fluid capacity for that TH 400 should be closer to 11 quarts unless you have an auxillary cooler added in or external filter setup. Should be 7 quarts in the pan and 4 quarts in the torque converter. I almost always anymore with the price of oil going up buy house brand fluids. But I do believe in those Lucas products seen them in action and they do work.

Maybe you can answer this one I understand the fact that oil is up in price so price of a quart goes up. But why when oil goes up synthetic oil also goes up.


JD  

Type F in a TH-400 good luck with that. The BIG BOYS use the purple stuff in high powered race cars with mega buck motors and drive train but for a street guy ???????  

dextron 3 is normally what is used...

TYPE F is slightly different...   and when i worked at a chain transmission shop.. before any over drives..  we used TYPE F in everything...

it will work... it is slightly thicker ...

it has been used to aid slightly worn transmissions..  takes up clearances... makes them shift again...    the thicker base oil seems to lube better...

the only draw back is when you run a dacron filter..  do to the thicker base oil...   it might result in less lube pressure at really high speeds..  i have not verified this..    most th350's and TH400's have screen type filters available.. or dacron..

the dacron looks like smashed fiberglass.. but it is actually plastic fibers...    

i did have a plastic screen TH350 filter... that would swell up and block the fluid flow when the trans came up to temp.. but that was almost 20 years ago..

the super thin purple stuff.. might not have enough viscosity for a bushing long life on the street...

since a th400 uses like 11 or 12 quarts on a fresh rebuild...  and only 4 or so.. when doing a filter service.. i have several friends who use 2 quarts of dextron 3 and two quarts of type ***  just to be safe..

for the ultimate TH400...  there have been conversions to torrington needle bearings instead of bushings on some of the heavier loaded bushings..   these needle bearing units were used for towing large trailers..... with huge transmission coolers that have dedicated cooling fans...  

The TH400 is pretty much grenade proof if it was rebuilt by a reputable shop.I have had mine in for over 15 years and it's been pounded hard with several hundred passes at the local strip with no signs of slowing down.I have a 2800 stall converter and a shift kit that was installed when it was built.Since the rebuild it was filled with mobil 1 synthetic tranny fluid and I have used nothing else since. I don't know about the purple stuff but I don't think you can go wrong with a synthetic fluid.I would not use the type f stuff,Leave it for the ford guys.Remember you get what you pay for . I would pay a little extra on the fluid then pay for another rebuild down the road.A friend of mine also uses synthetic fluid in his TH400 that has a reverse valve body and a trans break. He has busted a few rear ends and u joints on some hard launches but never the trans. The choice is yours?  

I have been useing type F in my th400's for the last 25 + yrs with no problems,,never had a trans problem,,right now im useing it in a th400,,3700 stall speed,shift kit,with no problems,,,maybe ive been lucky the last 25 + years but i never had a problem with type ***