The leaking transmission output shaft bearing & seal allowed the fluid to soak and soften the undercoating all along the transmission and driveshaft tunnel.

I removed the goo down to the painted underbody, then used a car parts store brand of "Rubberized Undercoating" spray.

It went on like chocolate milk in a spray form and remained tacky, despite "drying" overnight.

Consequently, it nicked and scraped off at the slighted incursion during my driveshaft mounting work the next day.

Is there any *real* undercoating product out there?