Jeep SELEC-TRAC transmission/gearbox
dezso3
03-11-2010, 04:21 PM
If you go to this link, you will see a picture of a Jeep's SELEC-TRAC shifter, with it having different options between 2WD, full-time 4WD, part-time 4WD, and 4-LO. I'm just curious, what do all these denote? What is the difference between them? Specifically, what exactly is the difference between part-time and full-time four-wheel drive? http://www.wjjeeps.com/st_shifter.jpg
fredjacksonsan
03-12-2010, 11:14 AM
If you go to this link, you will see a picture of a Jeep's SELEC-TRAC shifter, with it having different options between 2WD, full-time 4WD, part-time 4WD, and 4-LO.
what do all these denote? What is the difference between them? Specifically, what exactly is the difference between part-time and full-time four-wheel drive?
2WD - self explanatory
4 PART TIME - this setting locks the front and rear inside the transfer case. Power is split evenly front and rear, and the driveshafts turn at the same speed. This should NOT be used on dry pavement, or any other surface where you have good traction; you can break drivetrain parts.
4FULL TIME - This setting UNlocks the transfer case. You are still sending power to the front and rear, but the differential in the transfer case allows the front and rear driveshafts to turn at different speeds. According to the owner's manual you can use this setting all the time (although in my experience it makes a bit more noise). You'll get less traction than in Part Time, but this is a great setting to use when the roads are icy/slushy in some spots and clear in others.
N Press Down - Neutral, used if you are going to tow with the wheels on the ground, OR when shifting into 4LO
4LO - Low range. For heavy going when you need maximum power, like in deep sand. This locks the front and rear inside the transfer case, just like 4 Part Time. It's about 2.67 times as low as the regular gearing, so your top speed will be much less - watch your rpms.
Shifting: going from 2wd to 4PT can be done up to 55 mph without an issue. Same with 4PT to 4FT. If you're going to use 4LO, slow to 3-5mph, put the transmission in neutral, and pull steadily and firmly through Neutral to 4LO. You will likely hear a clunk or have some gear clash.
Also, shifting OUT of 4wd and back to 2wd (or 4 wd PT to 4 FT) may require you to let off the gas a couple of times. The owner's manual says you might have to "untorque the drivetrain" twice to get it to shift. I usually have my transmission in "2" or "1", gas it and let off a couple of times until I hear the clunk that lets me know it is out of 4wd.
Hope that helps, read up in your owner's manual if you have one.
I'm going to sticky this thread, since the question has been answered several times in several different threads.
what do all these denote? What is the difference between them? Specifically, what exactly is the difference between part-time and full-time four-wheel drive?
2WD - self explanatory
4 PART TIME - this setting locks the front and rear inside the transfer case. Power is split evenly front and rear, and the driveshafts turn at the same speed. This should NOT be used on dry pavement, or any other surface where you have good traction; you can break drivetrain parts.
4FULL TIME - This setting UNlocks the transfer case. You are still sending power to the front and rear, but the differential in the transfer case allows the front and rear driveshafts to turn at different speeds. According to the owner's manual you can use this setting all the time (although in my experience it makes a bit more noise). You'll get less traction than in Part Time, but this is a great setting to use when the roads are icy/slushy in some spots and clear in others.
N Press Down - Neutral, used if you are going to tow with the wheels on the ground, OR when shifting into 4LO
4LO - Low range. For heavy going when you need maximum power, like in deep sand. This locks the front and rear inside the transfer case, just like 4 Part Time. It's about 2.67 times as low as the regular gearing, so your top speed will be much less - watch your rpms.
Shifting: going from 2wd to 4PT can be done up to 55 mph without an issue. Same with 4PT to 4FT. If you're going to use 4LO, slow to 3-5mph, put the transmission in neutral, and pull steadily and firmly through Neutral to 4LO. You will likely hear a clunk or have some gear clash.
Also, shifting OUT of 4wd and back to 2wd (or 4 wd PT to 4 FT) may require you to let off the gas a couple of times. The owner's manual says you might have to "untorque the drivetrain" twice to get it to shift. I usually have my transmission in "2" or "1", gas it and let off a couple of times until I hear the clunk that lets me know it is out of 4wd.
Hope that helps, read up in your owner's manual if you have one.
I'm going to sticky this thread, since the question has been answered several times in several different threads.
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