earear

Hi I'm new to this forum and just need some advice on what I know is a common CRV problem, the rear diiferential. My car is a 2008 petrol automatic, 92,000 miles. I've only owned the car for 7 months, it has a nearly full Honda service history. I had the car serviced at a local Honda dealer four months ago and asked them about the lumpy idling and slight graunch after I've reversed off my drive on full lock and then heard the noise just as I pull away. They said the car behaved like any other CRV and there was no issue. After looking on the internet I realised what the problem was and got a trusted local garage to change (and hopefully flush) the rear differential oil, but the problem is only improved, not eradicated. So I'm thinking of having the oil changed again but am concerned in case that doesn't sort the problem. I know a new differential would cost about £2500 and a used one can be bought for about £300/£400 plus fitting but I don't know how big a problem this could be and how soon. Any views on this would be appreciated.