Western General Insurance parts and labor not covered Calabasas, California

I purchased a used truck from Sunset Chevrolet in Puyallup Washington about one year ago and bought the extended waranty they offered me. I have been keeping up with scheduled maintanance as required and one month ago had the the rear differential serviced as part of that maintainance. the service people that did the work did not report anything unusual about the rearend.
day before yesterday on the way to work the truck started making a sqeeking noise coming from the rear.
I immediately called the dealer where I bought the truck and described the situation to the service person. he said bring it in so I started in that direction, a short two miles. 
on the way there the pinion bearing siezed up.
I then had the truck hauled on a flatbed the rest of the way.

Western General will cover the cost of the pinion seal, about $25.00 and the labor to install it,
but will not cover the replacement of damaged rearend, about $3,000.00

there was no sign of leakage at the time of servicing or under the vehicle where I park,
and all scheduled maitainance was being done.

I feel I kept my side of the bargain but Western General Insurance does not.

I will never buy insurance from them again and would suggest any one considering using them to do some research first to see how other customers feel.
sure wish I did.