pklaus

My 99 RX300's been making a strange sound for a while now. It does it every time the RPM's reach about 2100 and lasts through about 2300. Only happens during acceleration. It's a low humming/grunting sound. Almost sounds like it could be a vibration, but I'm not sure about that. My best guess is that it's a vibration that comes from the exhaust system. I've heard of these cars having exhaust issues, but I don't want to tear the thing up for a noise that might be benign. The performance of the car seems fine, but the grunt/hum seems to be getting louder and longer over time. Anyone had this problem before? Anyone know how to fix it? Thanks!

Thanks for the response, Lenore. Tons of good info in that post. The wierd thing is that there's pink trans oil all over the part Lexmex calls the transfer case, the part with the metal fins. I'm going to assume the leak is from something adjacent or above it for now, I guess, since the transfer case should be filled with gear oil. But this weekend....I'm going to change the transfer case oil because, who knows? Someone might have put ATF fluid in it. With those instructions and pictures, how could I pay someone to do it? Maybe I'll do the trans. fluid, while I've got it jacked up. What I really need to know, though, is where that trans. fluid is leaking, because it's worrying the crap out of me. I'll end up with the car at a dealership in the next couple weeks if I don't find it myself....oh well.

I'm definitely leaking ATF fluid. That much I know because it's pink and I had to refill some. But anyone know where it might be coming from? It looks like some of the seals might have been redone. The seal between parts appears to be red, don't know if they were that way from the factory or not. A mechanic told me that the trans may have been rebuilt/replaced (big surprise) Someone told me the front differential was leaking, but I thought it used heavier weight gear oil? I've also read in some other posts that the differential shares fluid with the transmission. I bought this 99 RX AWD a couple months ago with 64K miles on it and everything seemed fine. But recently I've noticed that there's a low hum and slight vibration when I accelerate through a turn. Now, to me, that would be consistent with a Front Differential problem and possible leak (low fluid) but if the front diff. shares fluid with the trans, and it's full, then is that low hum and vibration coming from something else? I don't think it's the trans because it seems to shift smoothly, and when I take off straight there's no hum. When I look under the car, there's trans fluid everywhere, on the axle, diff, etc., like it's leaking and splashing all over the place. It's a pretty slow leak, though. I filled it 3 weeks ago and it's still full. I couldn't be more confused. Anyone know where this low hum and vibration comes from when accelerating and turning at the same time? Is it related to my leaking trans fluid? Or do I have 2 seperate problems that need attention.