What are the two plugs on a transmission - 1994 Chevrolet Caprice Classic

I'm not familiar with your vehicle, however the principle is the same for virtually all auto transmissions.
Get underneath your vehicle and look on the transmission fluid pan. Somewhere at the lowest point you will see a drain plug.

The plug may either be a nut or a recessed square, or even a hex recess.

Undo the drain plug and allow the transmission fluid to drain into a large plastic dish/container.

The link below shows you generic images of drain/filler plugs. It is not your vehicle:
auto transmission filler plug Google Search

When drained, replace the plug.

Then look for the filler plug. It will be higher up on the transmission case than the drain plug. Again, it may be a nut or a recessed square/hex.

You then have to use bottles of transmission fluid to refill the transmission. It can be messy ... The small bottles of transmission fluid - they have small tubes attached - can be very awkward to turn upside down when you're under the vehicle.

Alternatively, if you have a a long tube and a funnel you can use it to refill the transmission via the transmission dipstick tube. It can take a while to fill it as the fluid is slow to go down the tube.

Be prepared to get transmission fluid everywhere ...

Replace the same amount of fluid that came out. Start the car and move it through its range of gears. Check the fluid level.

It's not a difficult job. The link below is an easy guide:
How to Add Transmission Fluid
The job is worth doing. It will extend the life of your transmission. Most people never bother. Transmission fluid is supposed to be changed every 20,000 miles.

Chevrolet recommends that the transmission fluid be changed every 50,000 miles, but Chevy intended the transmission to be serviced only by authorized repair shops. For this reason, the HHR does not feature a transmission fluid dipstick. However, the HHR's transmission fluid can still be checked without exotic tools.

It is important to check the fluid level only after the fluid has circulated throughout the transmission by shifting through the gears. Failing to allow the fluid to circulate will result in a false fluid level reading. Turn the engine on and shift through each of the transmission's gears with the brake pedal depressed and the parking brake applied. The car should be allowed to idle in each gear position for approximately five seconds. Turn the engine off, then climb underneath the passenger's side of the vehicle. A small plug is located on the passenger's side of the transmission. Remove this plug with a wrench. Turn the engine on and observe whether any fluid drips out of the transmission plug's opening. If fluid does begin to drip from the plug opening, the transmission does not require additional fluid. Turn the engine off and install the transmission plug.

If fluid did not begin to drip out of the transmission's plug, transmission fluid must be added. Turn the engine off, then remove the black breather cap from the top of the transmission. The circular breather cap twists into the transmission. Twist the cap in a counterclockwise direction until it detaches from the transmission. Because of the lack of clearance between the breather cap's opening and the bottom of the vehicle, transmission fluid cannot be poured into the breather cap opening. Attach a fluid pump to a quart-sized container of new transmission fluid. Insert the pump's hose into the transmission through the breather cap's opening. Turn the engine on, then actuate the pump until fluid just begins to drip out of the plug's opening on the side of the transmission. Screw the breather cap onto the top of the transmission, then install the plug with a wrench.

Depends on your engine.

1980 JEEP CJ-7 2.5L 4-cyl Engine Code [B]
CAPACITIES
Engine, GM without filter..........2.4 quarts[1]
Wix Filter ........ 51040
Cooling System, Initial Fill..........8.0 quarts
Automatic Transmission, A904, 30RH Initial Fill..........4.0 quarts[2]
Automatic Transmission, A999, 32RH Initial Fill..........4.0 quarts[2]
Automatic Transmission, Total Fill
3 speed A999, 32RH..........8.4 quarts
3 speed A904, 30RH..........7.0 quarts
Manual Transmission, 4-SPD, SR-4..........3.0 pints
Manual Transmission, 4-SPD, T176..........3.6 pints
Differential, Front..........2.5 pints[3]
Differential, Rear..........4.9 pints
Transfer Case,..........4.0 pints

1. Add extra oil when replacing filter. After refill check oil level.
2. With engine automatic transmission operating temperature, shift through all gears.
Check fluid level in NEUTRAL and add fluid as needed.
3. 1984-1992 Models with command-Track, add 5 oz of 75W-90 GL-5 to shift motor housing opening.

TORQUES
Oil Drain Plug.....25 ft-lbs
Manual Transmission T176
Fill Plug.....15 ft-lbs
Drain Plug.....15 ft-lbs
Manual Transmission SR4
Fill Plug.....20 ft-lbs

1980 JEEP CJ-7 4.2L 6-cyl Engine Code [C]
CAPACITIES
Engine, without filter..........5.0 quarts[1]
Wix Filter..... 51522
Cooling System, Initial Fill..........11.0 quarts
Automatic Transmission, A904, 30RH Initial Fill..........4.0 quarts[2]
Automatic Transmission, A999, 32RH Initial Fill..........4.0 quarts[2]
Automatic Transmission, Total Fill
3 speed A999, 32RH..........8.4 quarts
3 speed A904, 30RH..........7.0 quarts
Manual Transmission, 4-SPD, SR-4..........3.0 pints
Manual Transmission, 4-SPD, T176..........3.6 pints
Differential, Front..........2.5 pints[3]
Differential, Rear..........4.9 pints
Transfer Case,..........4.0 pints

1. Add extra oil when replacing filter. After refill check oil level.
2. With engine automatic transmission operating temperature, shift through all gears.
Check fluid level in NEUTRAL and add fluid as needed.
3. 1984-1992 Models with command-Track, add 5 oz of 75W-90 GL-5 to shift motor housing opening.

TORQUES
Oil Drain Plug.....30 ft-lbs
Manual Transmission T176
Fill Plug.....15 ft-lbs
Drain Plug.....15 ft-lbs
Manual Transmission SR4
Fill Plug.....20 ft-lbs

1980 JEEP CJ-7 5.0L 8-cyl Engine Code [H]
CAPACITIES
Engine, without filter..........4.0 quarts[1]
Wix Filter..... 51258
Cooling System, Initial Fill..........13.0 quarts
Automatic Transmission, A999, 32RH Initial Fill..........4.0 quarts[2]
Automatic Transmission, A904, 30RH Initial Fill..........4.0 quarts[2]
Automatic Transmission, Total Fill
3 speed A904, 30RH..........7.0 quarts
3 speed A999, 32RH..........8.4 quarts
Manual Transmission, 4-SPD, SR-4..........3.0 pints
Manual Transmission, 4-SPD, T176..........3.6 pints
Differential, Front..........2.5 pints[3]
Differential, Rear..........4.9 pints
Transfer Case,..........4.0 pints

1. Add extra oil when replacing filter. After refill check oil level.
2. With engine automatic transmission operating temperature, shift through all gears.
Check fluid level in NEUTRAL and add fluid as needed.
3. 1984-1992 Models with command-Track, add 5 oz of 75W-90 GL-5 to shift motor housing opening.

TORQUES
Manual Transmission T176
Fill Plug.....15 ft-lbs
Drain Plug.....15 ft-lbs
Manual Transmission SR4
Fill Plug.....20 ft-lbs

Oilman

The transmission case has a lower drain plug and an upper fill plug on the side of the transmission case. You need a special 17mm Allen wrench to remove the drain and fill plugs on the ******.Open the upper fill plug and add the specified GM ****** fluid till it dribbles out the fill plug hole.

Checking the Transmission Fluid

• It is important to check the fluid level only after the fluid has circulated throughout the transmission by shifting through the gears. Failing to allow the fluid to circulate will result in a false fluid level reading. Turn the engine on and shift through each of the transmission's gears with the brake pedal depressed and the parking brake applied. The car should be allowed to idle in each gear position for approximately five seconds. Turn the engine off, then climb underneath the passenger's side of the vehicle. A small plug is located on the passenger's side of the transmission. Remove this plug with a wrench. Turn the engine on and observe whether any fluid drips out of the transmission plug's opening. If fluid does begin to drip from the plug opening, the transmission does not require additional fluid. Turn the engine off and install the transmission plug.
  

Adding Transmission Fluid

• If fluid did not begin to drip out of the transmission's plug, transmission fluid must be added. Turn the engine off, then remove the black breather cap from the top of the transmission. The circular breather cap twists into the transmission. Twist the cap in a counterclockwise direction until it detaches from the transmission. Because of the lack of clearance between the breather cap's opening and the bottom of the vehicle, transmission fluid cannot be poured into the breather cap opening. Attach a fluid pump to a quart-sized container of new transmission fluid. Insert the pump's hose into the transmission through the breather cap's opening. Turn the engine on, then actuate the pump until fluid just begins to drip out of the plug's opening on the side of the transmission. Screw the breather cap onto the top of the transmission, then install the plug with a wrench.
  

THE 4T40 E 4T45 E AND 4T65 E THESE TRANSMISSIONS DONT HAVE A FILL TUBE WITH DIP STICK.THOSE TRANSMISSION VECHICLE HAS TO BE PUT ON A LIFT AND LEVEL. TRANSMISSION HAS A FLUID CHECK PLUG LOWER HOUSING TRANSMISSION JUST ABOVE THE OIL DRAIN PLUG.TO CHECK FLUID TRANSMISSION NEED TO BE OPERATING TEMPERATURE. WITH ENGINE RUNNING AND TRANSMISSION FLUID PLUG REMOVE IF TRANSMISSION FLUID POURS OUT. CHECK PLUG HOLE.YOU HAVE TOO MUCH TRANSMISSION FLUID IN TRANSMISSION.IF FLUID DONT DRIP OUT HOLE NEED TO ADD A PINT AT A TIME.IF FLUID DRIPS OUT SLOWLY FLUID CORRECT TO POUR TRANSMISSION IN TRANSMISSION RAISE HOOD LOOK ON TOP TRANSMISSION ON DRIVER SIDE FOR A RED VENT FILL PLUG.REMOVE PLUG USING A LONG LONG FUNNEL POUR TRANSMISSION FLUID IN THE VENT FILL PLUG HOLE.THIS VECHICLE THE DEALERSHIP HAS TO CHECK FLUID USING A LIFT.YOU CAN DO THIS JOB BUT IT WILL VERY DANGEROUS YOU CAN PUT CAR ON JACK STANDS WITH VECHICLE SITTING LEVEL. BUT THE DANGER PART COMES YOU HAVE TO SLIDE UNDER THE CAR WHILE ENGINE RUNNING TO CHECK FLUID.IF YOU DO THIS JOB HAVE FRIEND OR HELPER AROUND DONT WORK UNDER CAR BY YOUR SELF ALWAYS KEEP CELLUAR PHONE ON HAND FOR EMERGENCY.

Hello,
Manual transmissions have a fill plug and a drain plug on the side of the transmission. The fill plug is a little above the drain plug. Pull the fill plug and fill the transmission until the transmission fluid just barely seeps out and re-plug the transmission. That is the proper way to fill it. You will need a long stem funnel to give you the room you need to fill it. Your transmission requires a 10W30 weight motor oil, just like your engine. If you have a little time and 3 or 4 quarts of oil laying around you can pull the fill plug first and THEN the drain plug and let all the oil drain out. Then plug the transmission and re-fill it with fresh oil and this is a transmission flush for your transmission. You just saved $70 shop charge doing this. I say pull the fill plug first and THEN the drain plug because the last thing you want to do is pull the drain plug first and then find out the fill plug has welded itself and won't come out and now you can't fill the transmission. Fill plug first always.
Regards, Tony

TRANSMISSION DONT HAVE DIP STICK,YOU HAVE A CHECK PLUG LOCATED UNDER TRANSMISSION NEAR THE PAN ADJACENT TO THE ENGINE OIL DRAIN PLUG.CHECK PLUG IS A METRIC 11M OR 12M METRIC BOLT.TO CHECK FLUID CAR HAS TO BE LEVEL AND ENGINE RUNNING.WHEN YOU REMOVE CHECK PLUG, IF FLUID POUR OUT YOU HAVE TOO MUCH TRANSMISSION FLUID IN TRANSMISSION, IF FLUID SLOW DRIP YOU HAVE ENOUGH FLUID IN TRANSMISSION, IF NO FLUID DONT DRIP OUT WHEN CHECK PLUG REMOVED,ADD A PINT OF TRANSMISSION FLUID AT A TIME.YOU POUR FLUID AT TOP OF TRANSMISSION UNDER THE HOOD,YOU WILL SEE A RED VENT FILL CAP, REMOVE CAP, YOU NEED A VERY LONG FUNNEL TO POUR TRANSMISSION FLUID IN THE TRANSMISSION. IF YOU HAVE TRANSMISSION SHIFTING OR SLIPPING PROBLEMS,MOST TIME TRANSMISSION DUE FOR FILTER AND FLUID CHANGE IF YOU AT THE 60000 MILES TO 120000 MILES TIME FOR FLUID AND FILTER CHANGE.

Well I guess you have figured out there is no dipstick. There are two plugs in the rear transmission pan. The bottom plug is for draining and the upper plug is for for filling and checking. Trans must be in park with the engine running and fluid should stream from hole when full.

On the passenger side of the transmission, there is a fill plug and a drain plug. The fill will be the upper plug and it's the one you use to check to make sure you have the right amount of transmission fluid in your transmission. Manual Transmission, NV3500..........2 liters Manual Transmission, NV1500..........2.7 liters

Undo the plug with a wrench and if the transmission trickles out, your good to go. If there is no fluid trickling out, top it off and place the plug back in and tighten to (Manual Transmission NV1500 Fill Plug 17 ft/lbs) or (Manual Transmission NV3500 Fill Plug 44 ft/lbs)
Thank you for using fixya and be safe. Drain Plug 44 ft/lbs Drain Plug 27 ft/lbs