I have a 1980 f150. I believe it has a c4 3 speed auto. I am changing the filter/fluid in the tranny today, and the capacities are all over the map, and the BIG discrepency is the install instructions for the filter and gasket. In the haynes manual it says to use an RTV sealant on the pan gasket, and on the instructions with the kit (filter, filter gasket, pan gasket) it says DO NOT USE SEALANTS OR ADHESIVES ON THIS GASKET! in big bold letters.....what to do? The filter gasket is a stiff/felt material, and the pan gasket is a pliable rubber. It seems hefty. What to do? And how many qts. of fluid will I need to refill after I drop the pan and filter? Thanks!!!

 

I would follow the instructions that came with the gasket itself.

If those instructions say IN ALL CAPS not to do something, surely those instructions override those provided by an all-encompassing, generic book.

My 1981 Owner's Manual (which I'm assuming will be the same as a 1980 in this regard) says the C4 requires 20 U.S. pints (or 9.5 liters) which works out to a little over 10 U.S. quarts.

The book also has a footnote saying to always use the dipstick to determine final fluid quantity requirements.

 

2 more things i forgot to mention

1. I saw on a forum, here i think, that someone switched to 5w20 motor oil for tranny fluid. Advisable?

2. The guy at autozone where i bought the gasket and filter kit said the computer says 6 qts. capacity for a refill....whats up with that?

 

Skip the 5w20 oil!!! That trick is done on street rods and drag cars and makes very firm shifts but kills the tranny!!


Stay with Mercon/dexronIII or Type F for firmer shifting


No RTV needed on that gasket just make sure the surface is clean and you can use gasket shellac if you want.

If you are just going to dump the pain and are not going to drain the torque converter it is about 4-5 quarts.


I would drain the torque converter now to finish the job!!!!


It is also a good idea to make sure you have magnets in the pan to catch the metal (notice how these do not have filters but just a mesh screen) I get the round magnets at Radio Shack and they work great.

 

I'm thinking you must be confused and that perhaps you saw somebody do that with a manual transmission. Using motor oil in place of gear oil would probably work but I wouldn't recommend it.

In any event, no, don't even think about doing this to an automatic transmission! Motor oil doesn't have the friction modifiers needed by an automatic transmission's valves, bands, torque converter, etc.

You need to use a fluid that meets Ford Specification DEXRON-II Series "D" Automatic Transmission Fluid or equivalent.

I have no idea, the only thing I can do is show you what my 1981 owner's manual says.

If somebody here has a 1980 Owner's Manual or Shop Manual, that would be the authoritative source.

Perhaps Fordzilla80 has one of those manuals, you might PM him....

 

Agreed. That is the difference between the two "full" capacities.

In any case, do not overfill.

 

I have it nailed down with your guys' help I think. It is a ford C6 3 speed. Total fill (torque converter, total pump out) is 11 qts and change. Just dropping the pan/filter is around 6 qts. At first I thought I overfilled, then I drove it and shifted thru gears and it is about perfect. Thanks for all the help! Around 1980 there were so many options for transmissions I had to use the # of bolts and pan shape to figure out what I had to figure out the capacity. Initial fill according to
1980 FORD TRUCKS F150 PICKUP 5.0L 8-cyl Engine Code [F] - AMSOIL Online Product Application Guide

is 6 qts, and total fill is 11.9 qts.

THANKS!