I recently replaced the saildrive rubber seal and when I asked for the oil to refill the sail drive I was advised by Volspec that it had been changed to automatic transmission fluid, so I bought the required amount and filled the saildrive. On a recent trip to Lymington I bought repalcement oil and fuel filters and asked for a litre of the ATF to keep as a top up for the sail drive. I was informed by a very helpful assistant that Volvo had just issued a warning about using ATF in their saildrives following several cases of gearbox lockups in reverse, which had beed diagnoised as a failure in the lubrication. I immediatley drained the ATF and replaced it with the original spec engine oil. Be warned if you have had no problems with the original oil then stick to it do not change it for ATF.