The hydraulic roof pump leaks from the reservoir.

It will be in the trunk under a cover. But you must locate the leak before you do anything else.

Turn the key forward to the spot just before cranking, emergency break on, windows down (slightly or all the way, no difference), foot on break, roof unlatched and pushed back slightly. Once you push the roof up slightly, it should trigger a microswitch that allows the motor to turn on. If you listen closely, you can hear it. Can you hear the motor turning? If not, check the fuse and any microswitches. If they check good it could be the "motor." I say "motor" like that because its actually a pump to a hydraulic system. It sits in the trunk on the left wheel well. Its very easy to replace.
If you do hear the motor, go to the trunk and look at the system on the left wheel well. There is a hydraulic reservoir under the pump. If you cant see any fluid in there, that is your problem. To fill it, turn the T-handle on the pump counterclockwise. This will depressurize the system and also allow you to manually operate the roof. Next to the T-handle is a cap that requires an allen wrench to remove. Remove it and fill to the little dot inside a circle with hydraulic fluid. This can be a little trick to reach; I used a turkey baster!! After filling to appropriate level, put cap back on and then turn T-handle clockwise and secure it. Now operate the roof a few times with the button to build up some pressure. Now your roof should be operating properly!!

sounds like the fluid level to me ,it could have a small leak and might just need some oil

Check up the hydraulic power steering pump.
See picture below for 1.6, 1.8 liters Audi (4 cyl.) engines:

If you find leaks and noise when runing, the hydraulic vane type pump is damaged. The pump **** air inside and mix air with oil resulting foam. Therefore fluid volume inside steering instalation rises. Then pressure overflows oil from the reservoir. You need repair or replace hydraulic vane type steering pump.

The problem could come from the clutch master cylinder or the slave cylinder. The cause could be external or internal.

First check the fluid level in the reservoir. The reservoir could be independent of the brake system or using the same.

If the level is too low, air may have entered in the line and the hydraulic compression is affected. So first, adjust the level in the reservoir using recommended oil. (normally brake oil is ok).

Check for any oil leak starting from the clutch pedal following hydraulic circuit up to the transmission.
Your vehicule should have two clutch cylinders: the master and the slave.
The master cylinder is operated by your clutch pedal, it's located under the dash, fixed to the firewall and connected to the hydraulic line on the other side of the firewall. Check for any leak on the carpet, under the carpet and near the hydraulic connection. Pumping the pedal making that verification could help to detect leak. Then follow the hydraulic line going to the slave cylinder attached to the transmission making a visual inspection for leaks.
If for any reason some air entered the circuit, the line could be purged from air bleeding the slave cyclinder as you do bleeding brake component.
If there is no air, no leak detected then it's probably an internal problem that you can't see. Remove the cap from the reservoir, depress the pedal. If the oil is moving in the reservoir then the master slave is probably bad otherwise I would suspect the slave.
I'm not an Isuzu technician.
Some other Gurus could complement or correct my saying.
Hope it will help
Dan

Hello there:
Yes there is a hydraulic pump that has fluid in it.
depending on the unit you should be able to have the resivor topped off i would refer to the owners manual maintenance section for clarification it may be simply the hoses them selves are not tight or the seals are not tight and may be getting air in them ok
Best regards Michael

The most common reason for this is low hydraulic fluid. The noise is probably the pump running while empty. When fluid id present it dampens that noise. Behind the rear seat is the combination motor/pump/reservoir. With the top in the DOWN position, fill the reservoir with ATF and cycle the system a few times as far as it will go. Repeat until the reservoir will take no more fluid. If that works, it is only a patch fix. You must now inspect the lines, motor and cylinders for leaks. The fluid does not evaporate. If it is low, you have a leak. Karl at topgunwon.com

Your top is moved by an electric motor wich operates a hydraulic pump which moves two pistons which move the top.
The "oil" thet you see is probably hydraulic fluid leaking from the drain hole in the car near the tire.
You have a leak in the hydraulic system.
You need to start at the motor/pump/reservoir unit behind the seat and find the leak.
Most commonly, it is a bad line. Second in popularity is a bad cylinder(s). Third on the list is the motor/pump/reservoir.
If you replace a line, do them all. If you replace a cylinder, replace them both.

Karl at topgunwon.com

It's either a manual or electronically operated sunroof, it would be expensive and very useless if it operated with the use of hydraulic fluids. Just imagine the fluid reservoir and the pump of that baby just to operate the mechnism.