The proceedure depends on whether the truck is 2WD or 4WD. I just removed the 5-speed from my 1993 Ranger Splash 4WD two times last week. I have it down to about a 4 hour job now.
75W90
What is specified in your owner's manual.
redline
Manual will work, auto will not.
if you have to ask. dont attempt it... transmission rebuilds are monsterously hard.
screw into end of transmission.
Mercon works.
1400 buckaroos
75W-90 Gear oil
Gear oil, Best place to get it is at WALMART.
For a 1987 Nissan pickup, you should use Dexron II or III automatic transmission fluid if it has an automatic transmission. If it's a manual transmission, typically, a GL-4 or GL-5 gear oil is recommended. Always refer to the owner's manual for the most accurate specifications for your particular model and transmission type.
there is a fill plug on the side of the transmission towards the top if its not there then you have to add it while you build it but it should be there