What is the difference between part-time 4wd and full-time 4wd on my Wrangler?

Question

I own a 2002Jeep Wrangler. When I engage the 4WD the dash light indicates part-time 4WD.

Answer 1

Part time 4wd means that both the front and rear axels are locked together for maximum traction. Part time should only be used in slippery situations like snow and mud. If you use it on dry pavement it will wear your 4wd components and tires. Full time 4wd enables you to drive in 4wd in all weather from dry pavement to snow since it allows the front and rear axles to rotate at different speeds. A light only illuminates on the dash if you are in part time or low, it will not illuminate if you are in full time. the other three answers are wrong. obviously they arent jeep owners.

Answer 2

If it's like the '06 its in either 2H, 4H, N or 4L. Those are the positions on the shifter (it isn't a throttle) for the transfer case. According to my owners manual the "Part time" indicator illuminates when in 4H. The 4LO MODE indicator light illuminates when the transfer case is shifted to 4L. It also cautions not to attempt to make a shift when the front or rear wheels are spinning. "The transfer case is not equipped with a synchronizer and therefore the front and rear driveshafts must be equal for the shift to take place". The manual also states under the explanations for 4H & 4L that each locks the front and rear drive shafts together so I think that "Part Time" designator is maybe a bit of a mis-nomer. The Grand Cherokee has a different setup which does, I believe have a part time setup. Maybe they just used the same instrument panel and activated those lights because they were there. From personal experience if you want to shift the transfer case while sitting still make darned sure you have the transmission in Neutral. Try it in Park and (if you pull hard enough) you'll wind up needing a new transfer case shifter as it will break a nylon piece attaching the cable. The cable isn't sold separately and the entire shift unit has to be replaced at around $350. Luckily I did it while it was still under warranty.

Answer 3

Part time 4WD is just that, its only used on surfaces that allow at least one wheel to slip because part time 4WD locks the front and rear axles together mechanically. So if you try driving on dry pavement in part time 4WD and go around a corner the wheels will scrub the pavement because they can't spin at different speeds.

Full time 4WD is always engaged, or can be left engaged on dry pavement due to viscous couplers in the transmission/transfer case that allow the front and rear axles to spin at different speeds. These systems usually have a torque split of 50/50 or 60/40. As with the Jeep system it transfers power to the rear axle until a wheel slip is sensed and then the viscous couplers engage the front driveline. This system has the capability to send full torque to either axle.

Answer 4

Finally nice to see someone get it right. This is right out of the Cherokee service manual:

OPERATING RANGES
NV242 operating ranges are 2WD (2-wheel drive), 4x4 part-time, 4x4 full time, and 4 Lo.

The 2WD and 4x4 full time ranges can be used at any time and on any road surface.

The 4x4 part-time and 4 Lo ranges are for off road use only. The only time these ranges can be used on hard surface roads, is when the surface is covered with snow and ice.

You've got the NV231 T-case, but the 241 gives the better explanation.

Mike in Da U.P.
Jeep owner too...

Answer 5

part time 4wd means the transfer case only engages when traction is needed with a slip sensed. Full time mean 4wd is always engaged.

Answer 6

connormar9590 is correct. the others are wrong, it use to be that way. the "full" meant the tires were full, but peple thought it meant they could use it "full" time, so they switched. if you want to test it out yourself, put it in one of the two and turn in circles, if your jeep feels like its "hopping" then you have all 4 tires trying to move at the same time that setting is for offroad use only, the other woulf be for street use.

Answer 7

Part time 4 wheel drive acts kind of like AWD; it only uses all 4 wheels to drive the car when the 2 primary drive wheels spin.

Answer 8

it only engages 4wd when it detects tire slippage.

Answer 9

connormar9590 is correct on all counts. The others are wrong.