Slow tranny fluid drip - where to check?

[TX-TahoeLtd]

Hi,

 

I park my Tahoe (2000, 5.7, auto) on an incline in my driveway and about every 2 days or so there is a drop or two of tranny fluid on the drive way.

 

Because this is on an incline, I can't tell where it's coming from as the drop is coming off of the u-joint on the output shaft of the tranny, approximately about as far back as the space between the dash and where the center console begins.

 

I've wiped it all down and tried to figure out where it's coming from and haven't been able to locate it.

 

Where are the obvious places to check? Is this a common thing for a vehicle with 68k on it?

 

I'd like to keep her drip free as long as possible.

 

 

Ideas?

[asilverblazer]

I would start with the rear seal where the driveshaft is inserted mostly because they are easy and cheap to change.