1994 ranger in 3rd and 5th gears, it has a loud whine to it.

great question, no engine told and trans tend match HP of engine.
first off year 1989 no digital documents then'
so nobody scans 500 page full SM the or new (crazy rare)
so buy the real Ford manual used off ebay or amazon the real thing paper book is best
chitons is a rag. it mixes up 10 year of car in toxic mess. of lies and 1/2 truths but does have great safety advice sure but does not cover any one year fully or even 1/10th
'
answer #2
learn what box that is , its true name and find books on just that
first guess, is (wiki guided) NO this is 5speed.
Mazda M5OD transmissions

• M5OD-R1 - Ford Ranger, Bronco II, Explorer, Aerostar.
• M5OD-R1HD - Ford Ranger (4.0L V6 only)

yes>? bingo? but looking at box only matters in real world.
82 > 92 ranger
4-speed Toyo Kogyo TK4 a MAZDA box it is.!)

a tk4 if is that buy the TK4 manual
back then ford sold shop manual sans trans. and told you then
what box do you have and you say 4speed stick and they handed you the TK4 and billed you too much.
later others scan the book and put them up on the web due to so few pages and easy to scan

not easy to find , just me searching for it,

https://search.brave.com/search?q=4-speed+Toyo+Kogyo+++TK4+transmission+manual&source=web

i had the same problame in my 1989 ranger xlt 4x4 i speed shifted a trans that wasent ment to and my trans got stuck in second and wouldent come out had to take it somewhere to get the forks in the trans replaced turns out i bent the forks and it wouldent come out of second

the shift sinkcranizers are dry .may have to pull the shifter and use some white lithum grease on it work the shifter from gear to gear working in the grease drive the truck for about 25-30 miles and change trans fluid

Only thing I would do to confirm that, is get it on a hoist with someone inside, run it up to speed where noise is present and with an audioscope ( like a stethescope ) used by mechanics, listen and confirm that the noise is actually coming from transmission, and not elsewhere. Then get estimated from reputable transmission repair place before deciding.

gear, rear end gear, 95 may have trans built for fast, 94 could be for towing

If the whine is there than the main bearing is already worn adding fluid will not save it, you will have to swap it or rebuild it. sorry i know you were hoping for something better.

are u sure the alignment (side to side, up and down) of the trans on the bell housingis not out of spec, that will burn the bearings out very quickly.

The trans gearing is all the same, the rear end gear set is where final drive ratio is determined

the pressure plate and the clutch disk may need to be replaced

IT LOOKS LIKE YOUR FUEL PUMP IS GOING BAD