[Apex]

I feel like the performance of the VTM4 system in my truck has degraded. This could be the result of heavy use/abuse this past winter in deep snow. How wearable are the components of the VTM4, especially the clutches? What can be done about it? Has any one had similar issues? Here is the story...

I live on a loose gravel road with a decent grade (3-4%) and every time I back out of my driveway and start up the hill, I can easily brake the front tires loose. So I have a base line for how quickly the VTM4 engages since I have owned this truck.

Enter last winter and the ridiculous amounts of snow we got. I did get the RL stuck more than once and freeing it was a workout. I had to lock the VTM4 and go back and forth until it dug itself out. On one occasion the VTM4 light flashed more than once. It was hard on the whole truck, but I feel the rear drive saw a level of use that was maybe more than it was designed for.

That was months ago, snow cleared and loose gravel road is back. One day I noticed the VSA engaged as the front tires spun going up the hill. This has never happened before. Usually the VTM4 wont allow the front wheels to spin and the VSA never needs to react. Suspecting a lack of 4wd, I then locked the VTM4, tuned off VSA and floored it from a stop going up the gravel hill. The front wheels spun for about 1 second, and the truck accelerated. Is this normal??? because I seem to remember the front wheels not spinning at all with the VTM4 locked.

Anyway, I swapped VTM4 fluid. The old fluid smelled like burnt ATF. I added new fluid and went for a drive. The performance was the same.

Did I wear out my VTM4? Is my experience normal?

 

[MikeT]

If the clutch packs fail, you will not receive a notification on the dash (Blinking light, dummy light, ect). You have to manually test the system.

 

[chiph]

Drive for a few hundred miles and change the fluid again, and see what happens.

Chip H.

 

[Apex]

If the clutch packs fail, you will not receive a notification on the dash (Blinking light, dummy light, ect). You have to manually test the system.

That I understand. So how would a Honda Tech deal with this? I would guess they would use a scanner to override the VTM4 module and provide maximum voltage to the VTM4 unit. Then they would have to measure torque to the rear drive wheels. How would they do this? Is there even a spec?

 

[CUinaRidge]

That I understand. So how would a Honda Tech deal with this? I would guess they would use a scanner to override the VTM4 module and provide maximum voltage to the VTM4 unit. Then they would have to measure torque to the rear drive wheels. How would they do this? Is there even a spec?

To test it, the RL would have to be up on rollers...
like this.....

 

[Apex]

Update... To diagnose a vibration issue I removed the rear drive shaft and drove the ridgeline.

All I can say is wow, the rear drive does a lot more than I thought. Backing out on to the same dirt road as mentioned above, now the front tires spin to the point they dig holes and the truck barely moves. there is lots of torque steer during hard acceleration. Also, going wot off the line will produce juvenile, John Force style burn outs.

So the bottom line is even if my rear diff is worn, it is still very functional.

 

[zroger73]

Update... To diagnose a vibration issue I removed the rear drive shaft and drove the ridgeline.

All I can say is wow, the rear drive does a lot more than I thought. Backing out on to the same dirt road as mentioned above, now the front tires spin to the point they dig holes and the truck barely moves. there is lots of torque steer during hard acceleration. Also, going wot off the line will produce juvenile, John Force style burn outs.

So the bottom line is even if my rear diff is worn, it is still very functional.

That's neat. You can do that in a 2WD Pilot or Odyssey as well and don't have a drive shaft to remove.

As far as I know, there is no Honda-approved method for dealer to test the VTM-4 unit. There is a way to manually test the unit by applying battery voltage to the clutch coils then trying to turn each wheel with a big torque wrench to ensure the clutches hold. Putting the truck on rollers as shown above doesn't give any meaningful results since it takes almost no torque to turn the rollers. A 4-wheel dynamometer would suffice, though.

 

[breye]

From The Factory Service Manual

 

[cccbock]

Wow. If test on either clutch test is abnormal, replace differential.

I read that to mean the unit is not serviceable. OUCH!

 

[breye]

No internal parts showing up on the parts fiche.We all better look after this differential that's for sure.

 

[zroger73]

From The Factory Service Manual

What exactly does that test do? It says it is a clutch electromagnetic coil test, not a clutch test.

If it is just checking to see if the coil is open, shorted to ground, or shorted to B+, then the wheels wouldn't need to be raised off the ground for that. The computer is constantly looking for those conditions, anyway.

I assume the test is engaging the clutches individually to see if wheel rotation occurs. If this is the case, it's not a very good test because it can't test the actual holding torque of the clutches, unless...

The test may be sophisticated enough to actually use the ABS modulator to brake the wheel then apply throttle to a calculated torque value to make sure there are no wheel rotations until the designed torque holding capacity has been exceeded.

 

[breye]

Check Out Mechanical Testing: speedlever post #69
http://www.ridgelineownersclub.com/forums/showthread.php?t=2887&page=7

 

[zroger73]

Check Out Mechanical Testing: speedlever post #69
http://www.ridgelineownersclub.com/forums/showthread.php?t=2887&page=7

Yeah, that's the manual test I was referring to earlier, which comes from this non-Honda source:

http://mypage.siu.edu/jeepster/vtm4.html

 

[Apex]

I would be interested to know what the screen prompts are from the Honda scan tool.