Went out for a club ride today and started to experience a very loud rumble/grind type of sound from the Borg Werner T35 in my Magnette with an 1800 MGB engine. It was most prominent in first then less in second and even less almost inaudible in third until I got over 50 mph where it started to get a little noisy again. I drove it home after adding a 1/4 qt. of tranny fluid, hoping that would help, to no avail. Any ideas what's going on? Should I trailer it to a transmission repair shop locally. Will they know what to do with transmission out of a 1974 Austin Marina?
Jim 
58 ZB