Several people have reported this problem. Dealers claim the tanks and differential have to be removed at a cost of $3500. There's a difficult but very doable diy solution on youtube that takes about 6 hours to do without dropping the differential. Why do the dealers insist on doing the the most expensive repair. 2nd, GM knows about this problem, (there's a service bulletin out) but does not let the owners know about a possible procedure to prevent it. They claim the problem is caused by the sulfur buildup on the unit, caused by the sulfur in today's gas, although no other non-gm cars seem to have this problem. Their solution is to put a cleaner additive in the tank at every oil change to prevent it from building up. Why don't they tell people this? The additive is about $30 and you likely need 2 bottles, but at $60 every 5000 miles versus $3500 every 50000 miles... I actually did the youtube repair and it works. Total cost - $75 for the part, plus 6 hours of my labor. I would have paid a shop reasonable labor to do it versus doing it myself, but it's hard to find shops to do more technical repairs on Corvettes.