Yup, you called it, jgalt! It took them a while to eliminate all of the easier checks before they realized they were going to have to open up the diffy.

I am quite pleased - my warranty has paid for itself nicely. There did push back a little, though - originally, they were going to pay for the replacement of a valve that was causing the modulating idle, which cost about $190. But since the warranty inspector had to verify the differential repair, he also looked at a valve and decided it wasn't broken, but just clogged with carbon deposits, and so he decided not to cover it, since it's a "maintenance" issue, not a "repair" issue. Nice how he changed the company's mind on that one, huh? Well, considering my $2000 warranty is paying out about $2775 for everything else on this job, I decided to let the valve issue go. All told, I'm paying for the valve, a $100 deductible, an oil change, and the tax on all of it, which is going to cost me about $630. Any other claims I make on this extend-o-warranty are going to be ALL JELLY - up to seven deductibles included!