Yesterday I bought a 88 Rr classic 3.5 v8 auto that I had planned to use for some off road fun. But last night I was driving it and suddenly I could smell a burning then it seemed to slip out of gear I pulled over and smoke was comeing from then bonnet. On inspection the transmission oil cooler had burst and lost all it's oil. Today I have fitted a used oil cooler and topped the ATF up. But now it will only engage reverse. And occasionally wen I first it goes backwards is that the end for the box or can it be repaired / is it worth doing ???

try the filter in bottom of g/box take off g/box sump its a large flat thing.mine was blocked same result as yours
i replaced this refilled job done hope this helps

ps i did not have the blown cooler

if its just clutch pack A ,it can be repaired quite easily by removing bellhousing and pump housing