Changing tranny fluid on 4 speed--how important?

[txmnjim]

Well, I am currently overwhelmed with projects I am finding to do on my
1989 F150 300 I6 with 4sp standard transmission (the worse so far, is a
possible leaking rear main seal). Anyhoo, while under there I was looking
at the drain and fill bolts on the tranny and wondering if I should change it?
Its currently shifts fine and everything now, and the tranny seems strong.
If I do decide to change it out, how do ya'll go about refilling it and about
how much fluid does it take? Doesn't seem to be much room up there to
work with ;-(
Jim

[The Plankster Prankster]

the standard view toward standard trannies is that if there's enough fluid in it, leave it alone. it would be wise to check if you haven't already
that said, if you do choose to change it, its really quite simple. i assume you found the fill plug, as you commented about the lack of space around it. there is just enough space up there for that quart bottle of 90wt (facing upright) to get the tip in the hole. once its started, crush the bottle to push as much fluid as you can, then refill the same bottle (buy a gallon jug for this) and repeat. when it overflows its full.
and as you're up there messing with it, you would be wise to check that all bolts holding it together are still tight (i had one start dying for loose bolts causing fluid loss). a little red Loctite is good insurance on critical areas like this

[rbohm]

i usually recommend that you change the trans fluid in a manual about as often as an automatic, about once every two years or so. you still have bits of metal that get into the fluid from normal wear and tear, and they need to be removed every so often. by the way, same with the rear end as well.

[txmnjim]

Thanks fellas!
I will go ahead and change it as soon as time and money are available ;-)
Jim

[txmnjim]

Thanks fellas!
I will go ahead and change it as soon as time and money are available ;-)
Jim

Btw, any particular type of 90 wt tranny fluid I should get? And also, do I need to torque
the drain plugs back on? I hope their not prone to leaking?
Thanks,
Jim

[rbohm]

the drain plugs in a manual transmission are pipe threads, which means they are tapered slightly. as long as you get them tight you are good to go. as for the lube itself, i tend to prefer pennzoil or other name brand lubes. you might also step up to a synthetic lube as well. as for weight i prefer a 75w-90 weight for most applications.

[txmnjim]

Thanks Rbohm!