I have a 98 Rav4 all wheel drive 4cyl engine with automatic transmission. I was glad to find this forum as I have a need for information on this car, and it appears that is in short supply in any of the other sources I have tried. I was cruising along the highway the other day and all of a sudden WHAM, BOOM, VERY LOUD and metal sounding sounds coming from the rear end and the rear wheels actually seemed to intermittlently locking up. After stopping, I found it would still move slowly, but loud grinding coming from the rear. Had it towed home and when I checked it out, I found I could wiggle the rear driveshaft, more specifically where it entered the differential. The driveshaft it's self seemed OK and the slack was in the nose of the differential. Therefore, I have deemed it easier just to replace the differential as opposed to opening up what I am sure is a mess of chipped teeth and metal fragments. I could see that the seals had been leaking, but hadn't noticed any noise of any kind. Anyway, does this sound like the best course to take and if so, I'm wondering about the gear ratio. I'm sure it needs to be a match for the front and I've seen folks saying it is a 2.98 and also read somewhere it is a : 4.404:1. Were there several options in 98? In any event, I need to know for sure before I buy. can anyone out there help me?