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2003 Pilot EX-L 4wd
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Hello all! This info seems hard to find! Is my 2003 ex-l w/vtm-4 all wheel drive by default? Or front wheel drive? Seems to have the best traction in rain and nasty conditions of any car I’ve ever driven...
 

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Well over the years things change and improve as the AWD and 4WD differences get a bit blurred by marketing, hype, and technology.
The 1rst + 2nd gen Pilots have VTM-4 which sends power to both axles depending upon demand which tapers off as the vehicle gets moving. There is a VTM-4 lock button that only works in 1-2-R which trails off at 18 mph. Good system for bad weather.
 

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Hello all! This info seems hard to find! Is my 2003 ex-l w/vtm-4 all wheel drive by default? Or front wheel drive? Seems to have the best traction in rain and nasty conditions of any car I’ve ever driven...
From my previous post on the subject (from 15 years ago):

Variable Torque Management 4-wheel-drive (VTM-4)

Ensuring a high level of all-weather stability, traction and control is the Pilot's VTM-4 (Variable Torque Management 4-Wheel Drive) system. Unlike conventional on-demand systems that work only when the wheels are slipping, VTM-4 proactively delivers torque to all four wheels during acceleration for excellent dry-road vehicle dynamics as well as outstanding control in wet, icy and snow conditions. A unique "lock" feature is provided to maximize traction for extremely slippery or "stuck" conditions. A compact transfer case is bolted directly to Pilot's front-mounted transaxle. A two-piece propeller shaft delivers torque from the transfer case to a rear axle drive unit. Two computer-controlled, electromagnetically-powered clutches engage as needed to provide torque to the rear wheels.

The Pilot's innovative VTM-4 four-wheel drive system was designed to deliver outstanding traction, stability and control in all weather conditions as well as good medium-duty off-road performance. It was also designed to minimize the weight and packaging penalties associated with conventional four-wheel drive systems.

The VTM-4 system is unique in its operation. Unlike many competitive systems that use an engagement strategy triggered by wheel slippage, VTM-4 anticipates the need for all-wheel drive and engages the rear wheels whenever the vehicle is accelerating. Additional torque is applied to the rear wheels when wheel slip is detected, up to an approximate maximum of 50-percent in low gear. Another unique feature of the system is the VTM-4 Lock function.

Activated by a button on the instrument panel, the VTM-4 Lock mode delivers maximum torque transfer to the rear wheels to aid extraction from extremely slippery or "stuck" conditions. The feature works only when the vehicle is in first, second or reverse gears, and automatically disengages at speeds above 18 miles per hour.

When cruising under normal conditions, the Pilot provides front-wheel drive power for improved efficiency. Torque is proactively distributed to the rear wheels when the vehicle is accelerating or wheel slip is detected. The level of torque delivery, front to rear, is determined by the amount of acceleration (rate of change in velocity) and wheel slip (difference in rotational speed) and is controlled by a dedicated CPU with sensors in the braking, engine and transmission systems.

To avoid the weight and bulk of a conventional transfer case, VTM-4's torque transfer unit is a compact cast-aluminum housing bolted directly to transaxle. The transfer case is a single-speed, permanently engaged device without a low-range, reducing weight and space penalties while maintaining excellent on- and off-road capabilities. Attached to the front wheel differential's ring gear is a helical gear that provides input torque to the transfer unit. A short horizontal shaft and a hypoid gear set within the case turn the drive ninety degrees, move it to the vehicle center line and lower its axis by approximately 3.75-inches.

VTM-4 Engagement Modes:

There are three distinct modes of VTM-4 engagement:

(1) The first mode, called Acceleration Torque Control (ATC), works whenever the vehicle's throttle is depressed, even on dry pavement - a feature unique to the VTM-4 system. Sensors in the engine and transmission monitor vehicle speed and acceleration. The amount of torque applied, as directed by the system's ECU, is determined according to vehicle speed, the amount of acceleration and transmission status (gear setting). This benefits not only the Pilot's ability to gain traction from a standing start, before wheel slip occurs, but also its overall dynamic stability on both dry and slippery roads. Reducing the propulsive force carried by the front tires under acceleration reduced torque steer and cornering adhesion. Rear wheel torque rises smoothly from zero to a preset maximum in proportion to vehicle acceleration (both forward and reverse). During constant-speed driving, all power is driven to the front wheels for improved fuel efficiency.

(2) The second engagement mode occurs when wheel slip is detected. Differences in rotational speed between front and rear wheels are measured by sensors in the ABS system and monitored by the ECU. In response, the ECU commands an increase in torque delivery to the rear wheels. Torque application is adjusted according to the amount and the rate of change in wheel slip. As slip increase, more power is delivered to the rear wheels for improved traction.

(3) The third mode of engagement is VTM-4 Lock. Lock mode occurs when the driver shifts into first, second or reverse gears and depresses the VTM-Lock button on the instrument panel. When lock mode is selected at vehicle speeds below 18-mph, the system ECU commands a preset maximum amount of rear-drive torque to be delivered to the rear wheels for improved traction in very low-speed, low-traction, conditions. As control is regained and vehicle speed increases, the system gradually reduces rear axle torque until it is completely disengaged.

The maximum torque delivered to the rear wheels is sufficient to climb the steepest grade observed on any public road in America - 31-degrees (60 percent slope) - with a two-passenger load on board. The Pilot will also move from rest up a 28-degree (53 percent slope) dirt grade. On a split-friction grade (different amounts of traction at each wheel), VTM-4 automatically provides sufficient rear-wheel torque to help the vehicle climb a steep, slippery driveway to enter a garage.

Propeller Shaft:

The two-piece propeller shaft that carries torque from the transfer case to the rear-drive unit is made of high-strength steel tubing to permit a smaller diameter. Minimizing driveline dimensions improves both ground clearance and interior room. The cross yokes attached at each end by friction welding are forged steel for high strength and low weight. The center support bearing is rubber isolated to block the transmission of driveline noise from the interior of the vehicle. A low-friction plunger joint located near the center of the propeller shaft accommodates relative motion between front- and rear-mounted driveline components.

A tuned-mass damper inside the front portion of the propeller shaft cancels any bending tendency in response to powertrain vibrations. Equal-length, front-wheel half-shafts have a plunger joint at their inboard end and a ball-type universal joint at the wheel end. Rear half shafts are similar in design but use a double-offset joint at the inboard end and a ball joint at the outboard end. All universal joints are constant-velocity type.

Rear Axle Drive Unit:

The Pilot's rear axle drive unit consists of a hypoid ring-and-pinion gear set supported by a cast-aluminum housing which switches torque from the propeller shaft's longitudinal orientation to the lateral orientation necessary to drive the rear wheels.

A connection from the ring gear to each wheel's half-shaft is made by left- and right-side clutches. Each drive clutch consists of three elements: an electromagnetic coil, ball-cam device and set of 19 wet clutch plates which are similar in design to clutches used in an automatic transmission. Ten of the plates are splined (mechanically connected) to the ring gear while nine of the plates are splined to a half shaft.

When the VTM-4 system's electronic control unit (ECU) determines that torque should be distributed to the rear wheels, an electric current is sent to the two electromagnetic coils. The resulting magnetic field moves a rotating steel plate toward each fixed coil. Friction between that steel plate and an adjoining cam plate causes the cam plate to begin turning. As it does, three balls per clutch roll up curved ramps, creating an axial thrust against a clutch-engagement plate. This thrust force compresses the wet clutch plates, engaging the corresponding rear wheel.

Unlike mechanically actuated four-wheel drive systems, the VTM-4 system is infinitely variable. The amount of torque provided to the rear wheels is directly proportional to the electric current sent from the ECU and can be adjusted from zero to a preset maximum. This current constantly changes to deliver the optimum rear torque calculated by the ECU. An internal gear pump circulates VTM-4 fluid to cool and lubricate the clutches, bearings and gears within the rear drive unit. Use of high-strength, low-weight materials - such as die-cast aluminum for the housing - minimizes the bulk and weight of the hardware.
 

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Nobili spiritus embiggens pequeño sparus tyre.
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If that isn't enough fun reading, dig into my attachments, :) But yeah, welcome to a great, well-engineered traction system.

144492
 

Attachments

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And yes, IMO, it's really a FWD vehicle, with RWD assistance.
Yes it works, and in many cases works well.
I'll stop there as I'm not an expert on this.
I met Jack once, so I do know Jack.

I should link that YouTube about a VTM4 review, and when the Pilot in VTM4 Lock was Maxed out on a hill.
He had to wait a minute for this old 6 cylinder jeep with real 4WD go right by him and go up the hill LOL
 

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And yes, IMO, it's really a FWD vehicle, with RWD assistance.
Yes it works, and in many cases works well.
I'll stop there as I'm not an expert on this.
I met Jack once, so I do know Jack.

I should link that YouTube about a VTM4 review, and when the Pilot in VTM4 Lock was Maxed out on a hill.
He had to wait a minute for this old 6 cylinder jeep with real 4WD go right by him and go up the hill LOL
The VTM-4 system was first introduced on the Acura MDX and marketed with the slogan "Defeat Winter."
It was never intended for heavy-duty off-road use.
Its competition at that time was the Lexus RX - not a heavy-duty off-roader either.
That doesn't mean some owners won't fit mud-swamper tires and try to go far off-road.
But, if a Pilot with VTM-4 gets outperformed by a Jeep in certain conditions, all that demonstrates is that the Pilot is being used for a purpose for which it was never designed.

144524
 

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2008 Piot SE FWD, 2015 Pilot LX 4WD. 2005 GSX-R1000
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The VTM-4 system was first introduced on the Acura MDX and marketed with the slogan "Defeat Winter."
It was never intended for heavy-duty off-road use.
It's competition at that time was the Lexus RX - not a heavy-duty off-roader either.
That doesn't mean some owners won't fit mud-swamper tires and try to go far off-road.
But, if a Pilot with VTM-4 gets outperformed by a Jeep in certain conditions, all that demonstrates is that the Pilot is being used for a purpose for which it was never designed.

View attachment 144524
The system and it's slight variations works and works well.
I'm glad we now have a 2015 Pilot with it. My wife drives that usually.
It's awesome in the snow/slippery stuff for sure.
 

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Nobili spiritus embiggens pequeño sparus tyre.
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The VTM-4 system was first introduced on the Acura MDX and marketed with the slogan "Defeat Winter."
And that it does very well.


As muck fun as it may be to throw your Pilot into the mud rasslin' pit or scrape up the undercarriage with protruding geological formations, my guess is the crack team of Honda market researchers came to the conclusion that there are actually more people who would use the vehicle for driving in wintry conditions.
 
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