How to check maual trans fluids - 1990 Isuzu Trooper

check level of trans fluid - and level of coolant --old coolant can be brownish -- if it is trans fluid and level low possible trans cooler if internal in radiator can get into coolant but check fluid to make sure --

It doesn't have a dipstick because checking trans fluid isn't as simple as just pulling the stick and reading it.
Trans fluid level varies greatly with temperature and tolerances in today's transmissions are very close. If fluid is overfilled by a small amount it can raise up into the geartrain as the trans warms, the fluid churns and ingests air and the transmission fails. Simply overfilling the trans can lead to complete trans failure.
To get an accurate fluid level you have to use a scan tool to check the actual temperature of the trans fluid. Once the temperature is taken then a chart is used to see how many millimeters of fluid should show on the stick, and then a special dipstick is used. The stick has a stop that seats in a certain way depending on vehicle, and it's labeled in millimeters.
If you don't have a trans leak and no repairs have been done then your fluid is full and checking it is never necessary. If you do have to have the fluid checked then a shop with the proper equipment can check it for you in a couple minutes.

This info was copied from another site: 2007 Jeep Liberty you check atf when it did not come with dipstick

He either added the trans fluid to the engine oil or he is checking the wrong dipstick. CHECK THE ENGINE OIL LEVEL to see that the trans fluid is not in the engine. If the engine oil is full of trans fluid, do NOT START the car and now you need to change the engine oil and also add the trans fluid to the trans. If engine opil is ok, be sure to find correct dip stick for trans fluid. They should be marked accordingly.

don't know if your vehicle even has a trans temp sensor. if it did it would be located internally inside the trans pan in valve body. check your trans fluid level, color, and smell. worn trans fluid will cause trans shift issues. burned trans fluid is an indication your clutches are burning and slipping.

check fluid level in transmission.

I would take the bulbs out and put the trans in reverse, the check for voltage with a test light or multimeter. If no voltage is present then it's more likely a problem with the reverse switch which is located on the trans.

Auto matic trans? look for dip stick tube on either side of engine.
If it is a maual trans 5/speed look for a plug on one side of the transmission about half way to the top of the trans.

do not do trans flush if car has over 100,000 miles and has never been flushed. if its under 100,000 or has been fushed before it is an easy job. there is a drainplug on trans pan. take out drain fluid. new trans filter will come with new trans pan gasket in most cases. remove trans pan, fliter is behind trans pan

you don't need a fluid actually, you need a gear oil. Gear oil is for maual transission and also for the differencials. Go to any auto parts store and ask or just buy gear oil, that container should be included with the pump, so that more easier for you to fill it. Ok. f

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