Just wondering if anyone has had or have heard of the 4 speed autos leaking only in reverse?
What was the cause? Was it an easy fix?
Could its be caused by a recent auto service not done properly?

It has a blown rear servo cover gasket - common problem with BTR's. The rear servo applies the rear band for reverse gear

It's the cover on the LH side of the transmission, undo the bolts & replace the gasket.

Make sure you ask for a BTR93 rear servo gasket - the earlier models use a thinner gasket with o- rings, The 93 is a solid thicker gasket.