Ask Mr. Smarty Plants

From a previous Mr. Smarty Plants answer:

'Fantex' is a cultivar of Fraxinus velutina (Arizona ash). Rather, Fantex is a "sport", or mutant form, of ash that was selected and developed by Fanick's Nursery in San Antonio for its different leaf type—its leaves are smooth; whereas the regular F. velutina leaves are somewhat fuzzy on the underside. There is, however, great variety in the texture of the leaves of this species. Additionally, Fantex apparently has a thicker leaf and is sterile (producing no seeds). It is always grafted onto Fraxinus velutina root stock according to the Pima Arizona Cooperative Extension.

Because the "Fantex' is a cultivar of a native plant, we have no information on it in our Native Plant Database. We can tell you that the parent of this cultivar, Arizona Ash, grows naturally in Texas only in the Big Bend area of far West Texas, according to this USDA Plant Profile. This is a somewhat different environment from what you have in Selma, in Central Texas. You didn't say if there was a wound from which the sap was draining, or if it was just a general drip all over the tree. We know that the parent tree is very susceptible to borers. We have been hearing recently about the threat of the Emerald Ash Borer to native ash trees. We found a couple of websites on this pest: USDA Animal and Plant Health Inspection Service and Wisconsin's Emerald Ash Borer Information Source. Since we are gardeners, not plant pathologists nor entomologists, we recommend you contact the Texas A&M AgriLIFE Extension office in Bexar, Comal or Guadalupe counties for more information. 

Beyond that, you should consider the environment and the care your tree is receiving. Again, speaking only of the Velvet Ash component of your tree, here is a site from gardenguides.com on How to Take Care of the Arizona Ash Tree.  

Fraxinus texensis (Texas ash) is a different species altogether. You can read descriptions of F. velutina and F. texensis from Florida Cooperative Extension Service and compare them.

Fraxinus velutina

Fraxinus texensis