4H Question: 4x4
12-04-2007 | 02:30 PM
#11
JK Junkie
Joined: Jul 2007
Posts: 3,193
Likes: 2
From: Boston, MA
You probably would have noticed real quick that something wasn't right, if you tried it in august
12-04-2007 | 03:50 PM
#12
JK Enthusiast
Joined: Jan 2007
Posts: 498
Likes: 0
From: Mt Pleasant, PA
If you are going perfectly straight you are right, but as soon as you turn even slightly the front and rear drive shafts of the TC will want to turn at different speeds and the TC will NOT allow this....
Please if you like your jeep don't do it....
Please if you like your jeep don't do it....
12-04-2007 | 04:17 PM
#13
JK Freak
Joined: May 2007
Posts: 504
Likes: 0
From: Puerto Rico
X2 she really wont like it that's why its called part time 4wd
12-05-2007 | 06:59 AM
#15
JK Freak
Joined: Jul 2007
Posts: 532
Likes: 0
From: Calgary, AB, Canada
A good reason not to buy a used Unlimited. Can you imagine how many people don't know the difference and just leave it in 4wd all winter. I have not had the need to use 4wd at all yet, and we have some real ice around here right now.
12-05-2007 | 10:38 AM
#16
JK Junkie
Joined: Sep 2007
Posts: 3,306
Likes: 1
From: Long Island, NY
actually our differentials are open, so the tire spinning at different speeds is not at all a problem.
i cant see any problems other than the usual wear and tear......
the driveshaft argument may hodl some water, but on the highway they have to be spinning at the same speed anyway, so it wont matter
i cant see any problems other than the usual wear and tear......
the driveshaft argument may hodl some water, but on the highway they have to be spinning at the same speed anyway, so it wont matter
12-05-2007 | 02:00 PM
#17
JK Enthusiast
Joined: Sep 2006
Posts: 121
Likes: 1
Going around a corner (no matter how slight) each of the 4 wheels wants to travel a different distance. The outer front will go the furthest and the inner rear the least.
The only wat this is allowed is by either not linking the wheel to anything (ie, the non driving wheels on a car) or by having a differential between the wheels.
A differential allows one wheel to travel a different distance than another. (Actually, it allows the outer wheel to travel exactly the same amount faster as the inner wheel slows, but lets leave the details out of this...)
Now, since the front wheels travel a curve outside the track of the rear wheels, we also need some way to spin the drive shafts at different speeds. (if you don't believe this, take a tight corner in sand or snow and look at the resulting wheel tracks)
In a "Part Time" system, there is NO way to allow the driveshafts to spin at different speeds. The system expects to slip the wheels a little to make up for the difference. Because of this, 4WD can only be used on loose surfaces like dirt, snow, etc.
A "Full Time" or "AWD" system adds another differential between the drive shafts to handle the different speeds. This of course adds complexity and poses the same issues we have with open axle differentials. This is why you find some vehicles like the Land Rovers have a way to Lock the center differential.
Which is better? For true off-road, the Part-Time offers a far more robust solution. That is why it is still the most common on 4x4 vehicles.
If the street is the thing, then you should have a Full Time system like the Grand Cherokee can be bought with.
In any case, the best rule of thumb is: Use your 4WD on the street ONLY when its covered in snow. Even in rain, it's not a good idea as modern tires get good wet traction. Although, I usually do pop mine into 4WD for a few seconds in the rain on straight sections just so that the system gets some exercise. Over time it does help make the shifting a lot smoother.
The only wat this is allowed is by either not linking the wheel to anything (ie, the non driving wheels on a car) or by having a differential between the wheels.
A differential allows one wheel to travel a different distance than another. (Actually, it allows the outer wheel to travel exactly the same amount faster as the inner wheel slows, but lets leave the details out of this...)
Now, since the front wheels travel a curve outside the track of the rear wheels, we also need some way to spin the drive shafts at different speeds. (if you don't believe this, take a tight corner in sand or snow and look at the resulting wheel tracks)
In a "Part Time" system, there is NO way to allow the driveshafts to spin at different speeds. The system expects to slip the wheels a little to make up for the difference. Because of this, 4WD can only be used on loose surfaces like dirt, snow, etc.
A "Full Time" or "AWD" system adds another differential between the drive shafts to handle the different speeds. This of course adds complexity and poses the same issues we have with open axle differentials. This is why you find some vehicles like the Land Rovers have a way to Lock the center differential.
Which is better? For true off-road, the Part-Time offers a far more robust solution. That is why it is still the most common on 4x4 vehicles.
If the street is the thing, then you should have a Full Time system like the Grand Cherokee can be bought with.
In any case, the best rule of thumb is: Use your 4WD on the street ONLY when its covered in snow. Even in rain, it's not a good idea as modern tires get good wet traction. Although, I usually do pop mine into 4WD for a few seconds in the rain on straight sections just so that the system gets some exercise. Over time it does help make the shifting a lot smoother.
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