More likely u-joints if only when shaft turns.
There is a fill plug on the side of the transmission. Remove the plug and if fluid does not run out then insert your little finger in the hole and crook it. If you do not feel fluid then service it to full. If you are driving and hear a noise from the transmission, then it is to late.
The manual specifies only Subaru fluid. If this is not available Dexron III can be used until Subaru fluid is available. Noise and hard shifting will be the result.
There can be many causes for a whining noise in automatic transmissions. The least expensive thing you can try to eliminate the noise is to have the transmission fluid and filter changed. Some shops will only replace the fluid unless you ask for the filter to be changed, so ask.
what would cause a knockings noise in my boat 3560- 2004 transmission when in idle goes away when you give it gas
The wheel bearings of the Subaru should be checked. Worn wheel bearings create a whirling noise, that gets louder as the car picks up speed.
The A4LD transmission is the most common failure on early explorers. It's very likely that your transmission is failing.
Friction in the transmission system may cause whining noise when a car is accelerating. A poor engine or clutch assembly may cause the excess friction in the transmission system.
I'm going to assume its an automatic transmission. Is the millage higher than 50,000? If so try changing the transmission fluid.
A clunking noise when shifting gears on a K1500 automatic transmission, might mean a problem with the drive axle or drive shaft. Check all U-Joints to make sure they are working properly.
If it's a manual it's supposed to whine when reverse is used, if it's an automatic it probably just needs transmission fluid.
A whining noise in the transmission is usually an indication the transmission fluid is low. Check the transmission fluid and fill it to the recommended level.
If it is a manual transmission it may make a whining noise or, if it is really falling apart, a grinding sound. If it is an automatic, they usually don't make any particular noise. Most of the functions are pressure valves so the transmission just doesn't shift properly or won't move when in gear. If you are geyying a grinding noise but the transmission seems to be functioning okay you probably need to have the flywheel inspected to see if the starter is dragging or the flywheel has broken or cracked.