I HAVE A 1998 F150 WITH A 6 CYL ENGINE. I HAVE A SMALL COOLANT DRIP AROUND TRANSMISSION REAR ENGINE AREA. CANNOT LOCATE LEAK AREA.

There are none. The Transmission does not use water to cool it.

You will have to clarify behind the oil pan. Front of engine towards fan. Rear of engine transmission side. Or above the pan towards engine side. If there is coolant leaking from behind the engine (between the engine and trans) and is not running down from above eg head gasket or hose connection, chances are good that there is a frost plug leaking on the rear of the block.

use a mirror and trouble light , clean the engine and let dry the install a pressure tester, you should be able to locate the leak

Most of the time when I see coolant leaking at the rear/top of the 3400 engine, beneath the throttle plate area, it's usually coming from the intake gaskets. There is a coolant cross-over passage at the rear of both heads and as time passes the gasket will sometimes split along the sides of this passage and coolant will begin to leak out. It can be tough to see clearly whats going on in this area well enough to pinpoint the exact source of the leak so it may take a bit of time to find it. Often with an intake gasket leak the coolant will puddle on top of the block then drip down the rear side of the engine and drip off of the pan or transmission bell housing. Hope this helps you find your problem!

I would ask for a clarification request, but lets see if I can help you. Dependent on where the transmission is leaking would help greatly, but a few minor things to look at are such things like your transmission dipstick. Yes, the transmission dipstick, when removed, you'll notice a small "vent" hole in it, where it goes into the tube of the transmission dipstick. This is to allow the transmission to "vent", for if it weren't allow to vent internal pressures, then the front seal could start leaking as well as the rear seal of the transmission. If you're experiencing a leak around the transmission's pan's gasket, then a DIY (Do It Yourself), Transmission Service is in order. To know how to perform this task, I recommend a Haynes Manual (located at any Auto Parts Store), for your particular vehicle.

Should the drip or leak be at the front seal, which you will see evidence of the drip around the bell-housing or the part that bolts to the Engine, then the transmission would have to be removed to have the front seal replaced...However, BG® sells automotive products and they do sell a "Transmission Conditioner" that will lubricate dry seals or expand them to stop the leak. The old shade tree way (which I wouldn't recommend), is adding Brake Fluid to the transmission which causes the seals to swell and "perhaps", stop the drip.

Once again, should it need to be taken out to repair the front or rear seal(s), remember to clean the Vent Hole on the transmission dipstick or the problem will occur again.

Hope this helps,

~00 Buck~

"Still living on the Right Side of Dirt..."

That would be your heater box overflow making that drip on the transmission, which indicates that you have a leak in your heater core. Try disconnecting the hoses to your firewall which connect to your heater core and either blocking them or joining them together to see if the leak stops. If it does, you can leave them that way until you can get to your heater core and replace it.

need to identify where leak is coming from wipe clean bottom of transmission and check trans lines ,dipstick tube, rear seal ,pan for leak or drip start van and let run drive around block than park and recheck trans for leak if leak by where engine and trans meet than front seal anywhere else fix and or replace front seal two choices first can try a trans leak additive follow instructions carefully or need to pull trans to replace seal

It' s a guess. First I would for any engine frost plug leaking. If equipped with a block heater check it for leak (depending where it has been installed).
If I'm wrong let us know and we will go further.
Hope it will help
Dan

look at the valve covers, the valve cover gaskets have most likely hardened over the years and are not sealing now