Assist with Transmission

[petracolemanmu]

r 185,000 miles on this 1999 E320 4Matic Wagon.
This is my first post; I'm attempting to get things straightened out before I start wasting resources on this. No, I haven't come across the same set of symptoms anywhere else online, including in the forum's archived posts.

Please find below a list of symptoms...

whir or buzz as engine speed is increased or decreased. There's a kazoo-like sound coming from the intake.
The whine becomes more audible at engine rpms of 2,000 to 3,000. may simply be too muted to be heard below that.
From the very beginning, transmission acts independently.
Even after circling the block for five minutes, the transmission still takes two seconds to engage that gear after I move the shifter. transportation > halt > change to R > wait > engage R. The transition from D to R and P to R or D also features the identical pause.
When you first start the engine and move the gear selector, you might hear a tinkling or metallic clank. It hesitates without making a clanking sound.
I noticed a few minor engine oil leaks, but there was a significant amount of water dripping under the center of the car at first. It seems to have stopped now. I've kept the air conditioner off since I noticed the problem. It was extremely humid this morning after last night's severe storms.
Since I discovered the problem this morning, I have been afraid of becoming stranded if I drive it more than 35mph.

For the past five years, we've driven this car—which has a mysterious past—to and from work, school, and everyday errands. The only maintenance we've done is get the oil changed regularly.
Your assistance and recommendations are greatly valued.

[petracolemanmu]

https://www.amazon.co.uk/s?k=1999+e320

[scarlettmoorear]

Fluid level check should be done first and foremost.

The level of fluid is a major factor for any automatic transmission. Loss of pressure required will result from underfilling. When fluid is overfilled, it will foam. Pressure drop once more.

[petracolemanmu]

Will check it out after work tomorrow after it's delivered.
However, I do not anticipate being that fortunate.

[aidencr]

If you don't have the Mercedes aftermarket dip stick, checking the levels of the cold and hot fluids isn't easy. Another quick option is to take it to AutoZone or an equivalent store and get a scan; this will give you the essential information for repairs.

[alexander_lewisq]

The scan gets my vote. I don't understand how some people can justify spending $200 on a scanner while others can go crazy replacing parts they don't even need. Purchasing a vehicle of this vintage is a wise financial decision because you never know when you might need it.

You should start by checking the fluid level and condition. When the transmission fluid level is low, you'll notice your third and fourth symptoms. Although it isn't the sole reason, it is one of the most common ones.

Get the ones you can handle right now. Do the scanning at a nearby shop if you can. Before you do anything else, make sure you have the dipstick. If the fluid isn't red when you check it, get new fluid. As a workaround, add more fluid as soon as you notice it is low, then place an order for the filter kit and swap out the filters as soon as possible.