Coolant in the Rear Differential Part III

[jackkpts]

Just wanted to update you all and ask for any additional guidance. Back in June I mistakenly mixed two partial gallons of Honda VTM-4 fluid with a partial gallon of Honda coolant. I pumped in about 6-10 ounces of this mixture until I realized the mistake. I drained all of this out, partially filled the rear diff with some more VTM-4 fluid, drained again. Then I filled it completely with fresh VTM-4 fluid. Here is where I am at on this 2 months later.

My 2005 Pilot 4WD has been making a moaning noise while turning at slow speeds. At times, there is a slight judder as well. This started when I was on vacation back in mid June. I had just changed the VTM-4 fluid a couple days before I left. I noticed the problem a couple days into our vacation (I towed and launched a boat during this trip). When I got home, I bought a new gallon of VTM-4 and changed the fluid again. The moaning noise was still present, so I started doing more research.

I found a Honda bulletin about how water can get in through a vent tube. There is a procedure documented to do 8 figure 8s to see if the condition goes away. I did this and the condition did not. The procedure says to change again and re-test. I just changed my VTM-4 again from a new gallon, re-did the figure 8s, but the problem is still present. Now what?

The dealer was sure this would take care of it. He said they have never had one that two changes - or flushing as he called it - did not clear the problem up. I'm guessing that I might be looking at a significant repair. Is it possible to just disconnect the 4 wheel drive system and use my Pilot as a 2WD model?

I should note that I have done all maintenance myself. I changed the VTM-4 fluid at 17,300, 30,000, 64,000, 66,000 and now 69000 miles. I only used Honda VTM-4 fluid. I only tow my 1,800 lb boat once a year, about 700 miles. I have seldom towed anything else - trailer of mulch, lumber for a deck - maybe once a year.

 

[The_Jeff]

Don't drive around with just the front wheels. It's ghetto, could handle negatively, and your rear end might still make noise even if it's not being driven.

 

[dparm]

Just curious if you had any of the fluid analyzed -- could help steer you towards a failing component.

 

[IndyIan]

Was there water in the dif fluid after the boat launch? Cloudy oil? If so it could affect the dif but it should not be loaded at all in normal driving.
My parents 08 CRV had rwd clutch issues and there is a "resurfacing" procedure where they let the front wheels turn at idle while the rears are on the ground. It seemed to work.

Check for TSB's on your Pilot, probably one will cover your issue.

 

[meep]

Originally Posted By: eljefino
Don't drive around with just the front wheels. It's ghetto, could handle negatively, and your rear end might still make noise even if it's not being driven.


This isn't the torque-vectoring arrangement used on the mdx, right? That one is electronically controlled which could be... entertaining. Might be ok, might introduce other nuisance, but likely not any worse than what you have now.

Provided it's just the hydro-mechanical setup, if you are in a bind I think you could roll in 2wd. There is likely enough static friction in the clutches that the whole mechanism will freewheel just fine. If it does cause any clutch engagement, it will be so small you won't notice, and with no load to drive, won't generate any appreciable wear or noise. The diff itself is open so I don't see any noise there.

 

[unDummy]

Now what? Replace the broken component.

Keep driving, change the VTM4 fluid every 10k-20k, and turn up the stereo.

No point in flogging a dead horse.

And, make sure there are no other causes of the noise. Low tire pressure, u-joints, wheel bearings, defective tires, steering...

Antifreeze as a solvent to the resins/glues that hold the clutch material together? Just keep driving until it fails!

 

[cchase]

This really sounds like a coincidence to me. Having some coolant in the diff oil for what sounds like 5 minutes, I would be very skeptical of ruining any components.

I could be wrong.

 

[jackkpts]

To answer a couple of the questions posed here. This is the same rear diff system as on the MDX, which is different than the CRVs. I did not notice any cloudiness of the fluid I drained after our trip. I did keep that fluid and the fluid I just drained, though I used the same oil drain pan I use for everything else. Not not sure if it would be useful for an analysis because of this. There was no metal on the magnetic drain plug with either change.

 

[meep]

you could experiment by disconnecting the solenoid lines to the rear diff. That will keep it from trying to engage the L+R clutches. It will still have the "10%" lockup that is always present, but not the additional computer-controlled force. I'm sure if you do this, you'll get some sort of an idiot light but it will certainly confirm if it's angry clutches or not.

M