IX MR, 35-40 autocrosses (BSP), 30-40 runs down the dragstrip, moderate to heavy street usage, 345 whp/wtq, ACT HDSS w/ 6 puck disk, around 100 or so "launch control" launches @ 5600rpm. Regularly maintained (clutch @ 12000mi, now has 21000mi), oil every 3000. Transmission shifts fine (typical cold weather stiffness). ACD appears to not have any faults.

Here's the deal:

ONLY when cruising above 40 or so, in any gear, there is a slight hum. Lightly accelerate or release the throttle and the humming stops.

Trans fluid changed with clutch job (diaqueen). Unsure about the transfer case. Rear end changed yesterday (diaqueen LSD) (no help, not worse or better) but considerable shavings on the magnetic drain plug.

After a few days of searching EVOm I'm thinking there may be some shaft play somewhere in the transfer case.

Your thoughts?

(humming is so slight that having the stereo on or dropping a window makes it un-noticeable)

thanks!

 

??? Unsure as in you've never changed it?

With that kind of hard use I'd change trans, transfer and diff every 10K mi or less

transfer takes GL-5 90wt LSD

ACD pump for TC takes the Diamond ATF SP-III

you've got some whine from things loosening up. IF you keep those fluids fresh it will last longer.

BG lubricants makes LS-II, Syncro Shift-II, and MGC

Have had some luck with BG products silencing gear whine on other Japanese vehicles. But ask the rep first whether these are compatible with your specific application.

 

If you can't hear it over the radio on low I wouldn't worry about it as long as everything else is in order.

It's also somewhat normal to see some metal chips with a clutch type LSD as the plates are always wearing.

Whats the condition of your tires?

As for fluids I always go by this: http://www.teamrip.com/faq.htm

NWM Tech are you sure about the TC using ATF? Or is this just for the ACD pump? I've never heard of that. I'd also shy away from the BG product as the Redline stuff is better for this application.

 

NWM Tech - this is incorrect information. The TC takes Diaqueen LSD fluid.

Agree with kekek - there are better fluids over BG.

 

sorry, correction is the TC takes the GL-5 90wt LSD, the pump for the ACD in the TC uses the ATF

my info on BG is from use in other makes, IDK specific applications to Mitsu per additives.

just changed the diff, trans, TC in a IX yesterday, they were pretty dirty at 37K mi.

Would def recommend change them at 30K, the TC only holds .63 qts so it doesn't have much volume, may wear fluid faster because of that.

there's no factory rec interval for changing/flushing the ACD pump but I'd rec every 60K. Have always done brake hydraulics at 30K to 60K, and it's similar heat/pressure to brakes.

 

some good info there

concur with what they say about the TC on the EVO, it's got a low volume

""Road racing applications may add an additional 1/2 pint of oil to the transfer case for added lubrication and cooling.""

 

I had the SAME problem, I just changed my fluid out for Redline Synthetic Shockproof Lightweight. No more whine at all! I've always used that stuff in my DSMs and i've always been happy with it.

 

slight winning noise can also be the ring and pinon in the t-case.... The only thing that should ever be used in the transfer case on these cars is Mistu DiaQueen. Period! I own a transmission shop, and work on evo's everyday, and i see so many of them come in were the fluid was changed, not with DiaQueen, and 3-5k later the ring and pinon is wore out, and thats when the winning noises start. From the factory the transfer case has way to much back lash, and once the clutch is upgraded, and you get one hard launch and the t-case breaks! Best thing to do even if your not having any problems with your t-case now is to pull it out, and have it re-shimmed, then is good to go! DiaQueen is GOLD for these t-cases. I also only use DiaQueen in the rear end........

 

i also have the same "whinning/humming" noise. its almost the same sound you get when car is stopped and idling, with foot of clutch in nuetral from throw out bearing.i have a 06 mr with 5 speed trans. 19k on car (25k on tranny). if i am in 4th or 5th gear around 2200-3000 rpms and let off the gas completly i hear it. sounds like its in rear seat area. soon as i barely get back on gas it stops. seems that its fine when drivetrain is under a slight load, but makes noise when there is no pressure/load on anything. if radio is on or window down you can never tell. i have had multiple people in car and most cant hear anything, but im really picky about little noises/defects. thinking on changing fluids and see if it helps. my dad says its just the play in drivetrain and is normal. other guy told me his has done it since he owned his.

 

^^^^Sounds like its the Ring and Pinion inside the transfer case. That slight humm will turn into a very loud howling whine eventually. All it takes is one launch and can kill the ring and pinion. Every car is different though. Best bet to send out to Shep for a stage 2 and never worry about it again.

 

it seems like it only does it sometimes. i couldnt here it when i drove it yesterday

 

A noise when the clutch is out with the trans in neutral engine running is probably a trans input bearing. Think about it. If the clutch is out the trans is engaged, but since it's in neutral only the input side of the gears/shafts are turning. The throw out bearing only turns when the clutch is pushed in, because that's the only time it's touching the rotating pressure plate.

A noise on decel from the rear is probably diff backlash, the ring/pinion is not perfectly clearanced. Not really an issue to worry about unless it starts getting worse.