Trans fluid overflow in filler pipe after 3 month winter layoff

it is pluged up it could be over flow tube or tranny line

"How do I get the air out of my hydraulic system"?

Remove the reservoir plug on the motor pump. Leave the plug out and do not put back until you have finished.

Fill the reservoir 3/4 full with fluid (to the bottom of filler plug hole). Put a rag under the hole to catch overflow that will occur as system fills.

Run the pump for 15-20 seconds. Stop. Check your fluid level and refill to bottom of filler hole. Continue running the motor in the same direction for an additional 15-20 seconds. When the top gets to the end of cycle, check your fluid level, fill to bottom of filler hole, and run the motor in the opposite direction.

You are literally running the top all the way up and down sereral times. Checking the fluid level as you go and fill as required, leaving reservoir 25% empty.

When you are no longer able to add fluid, put the top in the down position. Check the fluid level one last time, should be to bottom of filler hole. Put the plug into reservoir.
"How do I get the air out of my hydraulic system"?

Remove the reservoir plug on the motor pump. Leave the plug out and do not put back until you have finished.

Fill the reservoir 3/4 full with fluid (to the bottom of filler plug hole). Put a rag under the hole to catch overflow that will occur as system fills.

Run the pump for 15-20 seconds. Stop. Check your fluid level and refill to bottom of filler hole. Continue running the motor in the same direction for an additional 15-20 seconds. When the top gets to the end of cycle, check your fluid level, fill to bottom of filler hole, and run the motor in the opposite direction.

You are literally running the top all the way up and down sereral times. Checking the fluid level as you go and fill as required, leaving reservoir 25% empty.

When you are no longer able to add fluid, put the top in the down position. Check the fluid level one last time, should be to bottom of filler hole. Put the plug into reservoir.

Why do you want to add it? Wipe the dipstick on clean white paper towel or cloth. If there are no leaks and the colour is still fairly bright it should be ok. If there are no leaks and the transmission is slipping it needs to go to a dealer or tranny shop.

Transmission Fluid Fluid Level Checking & Filling To Check:

1. Connect a scan tool to the vehicle to read ATF temperature. ATF checking temperature should be 95° - 113°F (35° - 45°C).
2. Start the engine.
3. Raise and safely support the vehicle.
4. Place a drain pan under the transmission.
5. Allow the ATF temperature to reach 95° - 113°F (35° - 45°C). Automatic transmission fluid inspection plug
   
   
6. Remove the inspection plug from the transmission housing. Fluid is pipe will run out. If fluid continues to drip out, no additional fluid is needed. If only the fluid in the overflow pipe runs out, additional fluid is needed.

To Fill:
Automatic transmission fluid filler pipe

1. Pry the cap from the filler pipe. The cap locking device will be destroyed during removal.
2. Pull the plug from the filler pipe.
3. Add fluid slowly with VAG 1924 or equivalent until fluid runs out of the inspection hole. Install the inspection hole plug.
4. Install the plug in the filler pipe and secure with a new cap.

Fluid Level Checking & Filling To Check:

1. Connect a scan tool to the vehicle to read ATF temperature. ATF checking temperature should be 95° - 113°F (35° - 45°C).
2. Start the engine.
3. Raise and safely support the vehicle.
4. Place a drain pan under the transmission.
5. Allow the ATF temperature to reach 95° - 113°F (35° - 45°C). Automatic transmission fluid inspection plug
   
   
6. Remove the inspection plug from the transmission housing. Fluid is pipe will run out. If fluid continues to drip out, no additional fluid is needed. If only the fluid in the overflow pipe runs out, additional fluid is needed.

To Fill:
Automatic transmission fluid filler pipe

1. Pry the cap from the filler pipe. The cap locking device will be destroyed during removal.
2. Pull the plug from the filler pipe.
3. Add fluid slowly with VAG 1924 or equivalent until fluid runs out of the inspection hole. Install the inspection hole plug.
4. Install the plug in the filler pipe and secure with a new cap.

Transmission fluid level: As you dont have an ATF dipstick, you will have two plugs facing downward on the larger trans pan. The plug higher up on the pan is the fill/level check (stamped/recessed into the rear right corner of pan).

ATF should just dribble from this plug on a hot, idling truck, in neutral on a level surface. The lower one is the drain. The one at the back of the pan in a recess is the filler.

You need a hand pump or something similar to fill it to overflowing then top it off with the engine running. Make sure you shift through the gears a couple of times when topping off.

You dont have an ATF dipstick, you will have two plugs facing downward on the larger trans pan. The plug higher up on the pan is the fill/level check (stamped/recessed into the rear right corner of pan). ATF should just dribble from this plug on a hot, idling truck, in neutral on a level surface. The lower one is the drain.

The one at the back of the pan in a recess is the filler. You need a hand pump or something similar to fill it to overflowing then top it off with the engine running. Make sure you shift through the gears a couple of times when topping off.

As far as I have found the 02 Isuzu Rodeo does not have a transmission fluid dipstick you have to in fact go under your vehicle to check, change and fill your transmission fluid. Transmission fluid level: You will have two plugs facing downward on the larger trans pan. The plug higher up on the pan is the fill/level check (stamped/recessed into the rear right corner of pan). ATF should just dribble from this plug on a hot, idling truck, in neutral on a level surface. The lower one is the drain. The one at the back of the pan in a recess is the filler. You need a hand pump or something similar to fill it to overflowing then top it off with the engine running. Make sure you shift through the gears a couple of times when topping off.

Transmission fluid level:
This type of vehical has a sealed transmssion and there's no way one can check the transmission fluid level. There are two plug at the bottom of the transmission the drain and the filter.
As you don't have an ATF dipstick, you will have two plugs facing downward on the larger trans pan. 
The plug higher up on the pan is the fill/level check (stamped/recessed into the rear right corner of pan). ATF should just dribble from this plug on a hot, idling truck, in neutral on a level surface. The lower one is the drain. 
The one at the back of the pan in a recess is the filler. You need a hand pump or something similar to fill it to overflowing then top it off with the engine running. Make sure you shift through the gears a couple of times when topping off. 
Good luck and hope this helps

Most automatic transmissions do not have a filler plug or cap. The transmission fluid is added by using a long-neck funnel, which is placed in the tube the dipstick for the transmission sits in. Be sure to test the level while the engine is running, with the transmission in either park or neutral. Be very careful not to over fill the transmission, and make sure that you have the right kind of transmission fluid for your vehicle.