I have a 5-speed 2006 IX. Starting at about 25K miles I started noticing a distinct whine coming from underneath the car every time I downshift and hit about 2000 rpm. I changed the transfer case & rear diff oil to AMS, and the noise remains. Is this transfer case whine, or something else? I don't hear it when I accelerate or shift up. Any ideas on how I can solve this problem?

 

TC and rear diff are the most logical. I'm not sure if the ACD TC's are the same but you can remove an inspection plate on the non acd and check the ring and pinion, get an idea of the mesh zone and back lash.

 

Most likely the rear diff...

 

i have the same whine all the time but i just rev match/heel toe to prevent the sound. Doubt its helping any of the components but at least i dont hear it.

 

Yeah - I notice it too. Also - if I leave the clutch engaged it sounds louder. The noise does not bother me too much - I just hope it's not a symptom of worse things to come.

 

It's absolutely normal.

 

Welcome to the Mitsu AWD platform. Noisy indeed I recommend careful rev matching and frequent FULL synthetic AMSOIL fluid changes for tranny, xfer case, and rear diff.

 

How frequently? I don't beat up my Evo (very often) and use it as my DD for about 25 mi every day.

 

I think the recommended mileage for drivetrain fluid is about every 10k-15k.

 

does amsoil make a non synthetic fluid? I thought it was all synthetic

 

that samething happend to me when i bought my evo i had about 23k on it got it from a dealership and about 3 weeks later i started to get a whine noise only on a down shift it ended up being bearings in the tranny was the problem $$$ about 900 to fix glad it had a 30 day warnt haha

 

i would just stay with diaqueen tcase fluid and rear end.


mine whines from like 40-70mph on the gas lightly....prolly my tcase going