Question:

Thanks for the reply….I am beginning to understand. I’m used to ol’ fashioned four wheel drive or no four drive. Thanks. – Hide quoted text — Show quoted text –

Response:

I have recently purchased a 1995 Explorer XLT w/ the Control Trac System. I am waiting for the owners manual to learn about my vehicle, but it is taking too long.  Can someone explain to me what the difference is between the standard 4×4 that I am familiar with and the Control Trac features? Thank You, Kevin

Response:

> I have recently purchased a 1995 Explorer XLT w/ the Control Trac System. > I am waiting for the owners manual to learn about my vehicle, but it is > taking too long.  Can someone explain to me what the difference is between > the standard 4×4 that I am familiar with and the Control Trac features? > Thank You, > Kevin

The Control Trac 4×4 feature senses the difference in speed between the rear driveshaft and the front wheels (beyond the normal differential difference in speed).  There is a driveshaft RPM sensor at the rear differential.  When the difference in speed goes above a certain threshold (indicating that one or both rear tires are just starting to spin), an electromechanical clutch in the transfer case (right behind the transmission) begins to apply power to the front driveshaft, thus driving the front wheels.  When you are pulled out of trouble and the speed between front and rear wheels is back to normal, the clutch disengages.  I read that the system applies power in 10% increments, up to 100% if needed (I suppose you could need this if your rear tires are hanging off a cliff !). The mechanism is an interesting assemblage of three balls and a circular ramp arrangement.  As the clutch sleeve is rotated electromechanically, the balls tighten up against their ramps, thus forcing a series of clutch plates together which engage the front driveshaft.  It’s also interesting to note that power for the front driveshaft comes from a large metal chain in the transfer case, powered off the shaft coming from the transmission.   The 4WD Low function is more like standard 4WD, where the front and rear driveshafts are always engaged together to really get you out of a muddy/snowy/icy mess.   I use this mode to pull the truck onto ramps to change the oil.  Have to watch so you don’t drive off the tall end of the ramps.   Mike <><><><><><>  WITNESS – Process Simulation and Modeling Software <><><><><>  Lanner Group, Inc.  31225 Bainbridge Rd.  Solon, OH 44139   www.lanner.com  Human: 216-519-1200         Fax: 216-519-1243         Amateur Radio KB8RJO <><><><><><><><><>   Good * Cheap * Quick  (pick any two)   <><><><><><><><>

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