What's the process for having things done under warranty?
 

I've never had to use one before on a car so not sure how it works.

I've got a 2012 WRX STI and I've been finding that sometimes it is a bit weird going into first. It will make a slight grinding sound and will feel as though it is trying to jump back out as you push it into gear.

Understandably, I'm not best pleased about it. It's an approved used car and we've had it a couple of months, so it has most of a 12 month manufacturer warranty on it.

Do you just ring them up and then take it in and they sort it all out, or do you generally have to pay up front for any diagnosis and reclaim it if there's a fault?

Phone up the Subaru dealer you bought it from, speak reasonably with the service manager and explain the symptoms. They will clearly need to assess the car, so make it clear that you bought the car from them with an Approved warranty, and ask if there's anything you need to do as you don't want to risk being out of pocket.

Of course, the car should have no obvious modifications from standard when it goes in for assessment.

It's completely standard but the dealer I bought from is a long way from home. I'd rather take it to my local dealer if I can.

Do as Flat4x4 said but call your closets dealership instead asking if they will take on the warranty :)