1971 F100 manual transmission
I'm replacing the 3 speed manual trans in my 1971 F100. Before I install the
replacement trans I'd like to put fresh fluid in. What is the best fluid to use for a
manual 3 speed trans of that age?
I use Royal Purple Synthetic, on a trans that old I assume you are going to replace the seals before you put it back in so going a full synthetic won't be a problem. If you don't want to full synthetic then just just use the standard gear lube from Royal Purple, your local parts store should have both in stock, if not it can be ordered overnight from them. Well worth the extra cost.
I have used Redline oils made specifically for vintage transmissions.