This can happen when the oil is to slick or to heavy. The synchro rings can't get a grip on the hubs and keep slipping as if the rings are worn. Did you use additives like slick 50 or Molybdenium in the past? Kees Oudesluijs NL [demime 1.01d removed an attachment of type text/x-vcard which had a name of coudesluijs.vcf]