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  • #16
    I agree with Northstar....

    When I started wheeling I thought 4wd was always supposed to be in.

    The guys I ran with frowned on it for trail rides. That is unless you are doing an obstacle, or hitting a mudhole trying to get stuck.

    "If you get stuck while in 4wd what are you gonna use to get unstuck" "winching takes too long"

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    • #17
      Originally posted by Northstar
      As a side note, I spent ten years driving tow trucks, we contracted with 7 local Police Agencies including State Police. So I developed my own opinions on 4wds at highway speed in the snow, based on my experience.

      If you were to look at it statistically, you could prove that Grand Cherokees are in fact the worst vehicle to drive in the snow, as opposed to being the best. This statistic could be supported by the fact that while they account for less than ten percent of the vehicles on the road, they account for more than a quarter of the vehicles upside down in the ditch during a snowstorm.
      Don't even get me started on the way every manufacturer advertises their 4WDs and AWDs blasting through snow at high speed in a completely irresponsible manner.
      I think that is more a symptom of drivers being over confident in the ability of their vehicle....I always notice that vehicles that have slid off the road are SUV's....people going too fast in a too heavy vehicle.

      My Commander kicks *** in the ice and snow...the TJ...well...it slides quite a bit.

      Comment


      • #18
        All good points. I prefer 4wd on slippery roads(at a safe speed-not 55+)Becuase the front end pulls, helping to keep you striaght. And we can't forget the old addage.."Four wheel drive can get you going faster, but it won't help you stop any faster" I think it all comes down to personal preferance and driving skill. I lock my hubs at first snow just so they are locked in, then use the T-case as needed. Usually 2wd is fine, and 4legged drive is just a lever away.

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        • #19
          I have in years past gone 50 mph in 4wd hi with little obvious problems... but it seemed to contribute to some premature axle wear in front.
          I cannot imagine trying to do 65+ in 4wd.
          But then, individual skill (and foolishness) is always a factor.

          I keep it under 45 in 4wd nowadays.
          If I get there early, is someone going to take my parking spot?

          Comment


          • #20
            you can run 4X4 at any speed you want. i've run 4X4 at highway speeds in the snow and got great traction. never had a problem with it. think about this a minute...there are vehicles that are FULL TIME 4X4...howinthehell do they run on the highway if you can't run 4X4 over 40 MPH.

            this thread is proof you shouldn't believe everything you read on an internet board.

            word........

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            • #21
              Since 4-wheel-drive is only supposed to be activated on the highway when all tires are on a slippery surface such as ice or snow or gravel (using it on a hard surface causes excessive driveline wear because the Jeep TJ 4 wheel drive locks front and back together), I fail to see the need to know how fast you can go in 4-wheel-drive mode. If you are on a surface slippery enough to use 4-hi, you shouldn't be going faster than 35-45mph in the first place.

              One thing I *will* say is that 4-wheel-drive does *not* cause a Jeep to spin out more than rear-wheel-drive. Or front-wheel-drive, for that matter. I once did a 360 in a 1981 Honda Civic when I hit some black ice in a curve (luckily I was going very slow because I knew the road was icey, so I came to a rest against the curb without flipping over it). It's the amount of weight per square inch of tire surface area that most drastically affects traction on ice and snow. More weight lets the tire "bite" into the surface better. Thus why my Civic did its slow-motion spin... a front-wheel-drive Civic has virtually no weight on the rear tires. Adding power to the rear tires, like on a pickup truck or SUV, makes it even easier to spin. I daresay that most of the Jeep Grand Cherokees that you see spun out on the highways during snowstorms were in two-wheel-drive mode at the time they spun out. Heck, most purchasers of a Jeep Grand Cherokee wouldn't have the foggiest clue as to how to get it out of 2HI.

              Furthermore, because the Jeep TJ 4x4 system locks the front and back axles together, the guy who said that it "takes time to respond" is wrong, wrong, wrong. It's always there when it's on, the front and back axles are locked together, period, that's why you're not supposed to use it on a hard surface at highway speeds, because it will bind and cause drivetrain wear or damage. A full-time system, which has a limited slip differential action in it to allow the drivetrain to go around corners on hard pavement without binding, may take time to respond (it depends on the system, some use electronically-controlled clutches, some use a hydraulic system that takes time to heat up enough to "lock" front and back, some use planetary gears or a Torsen system). But the TJ's "part-time" system has no such problem, since it has no differential action in its transfer case.

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              • #22
                heavier vehicles will get traction better when taking off, but when trying to stop on a slippery surface, the heavier vehicle just keeps sliding.

                many fulltime 4X4 vehicles have open diffs. i know this for a fact because i've owned some.

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                • #23
                  Hi, I was referring to the center differential ("transfer case") in a "full-time" system having a "limited slip" action. As for whether other axles have a "limited slip" action, it depends. For example, I once had an all-wheel-drive Subaru (when I needed a snow car), and it had an electrically controlled clutch pack in the center to kick in the back axle when the front started slipping, and a disc-type limited slip differential in the back. The manual transmission version of the Subaru, however, used a hydraulic "transfer case" that always sent at least some torque to both front and back, but if one wheel started slipping it would heat up and the fluid would become basically a solid tying the front and rear together. Once again, this car had a disc-type limited slip in the back. On the other hand, my mother had an all-wheel-drive Honda station wagon (basically the predecessor to the CR/V), and it had the center hydraulic "transfer case" limited slip but no limited slip in either front or back. My brother got it stuck once at the beach with both the left front and left rear tires digging a hole into soft sand while the right front and right rear tires were on the hard-packed sand near the ocean. A limited slip differential would have gotten him out of that without requiring him to have a half dozen of his friends push him out.

                  The net effect on the automatic transmission version of the Subaru system was that if you accelerated around a corner and the front end started slipping (what causes understeer in front-wheel-drive cars), the rear end would suddenly kick in and cause an oversteer situation. To say that this was exciting is an understatement. But the Jeep TJ's "part-time" system is nothing like this, so you don't have to worry about it with the Jeep TJ.

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                  • #24
                    i'm too tired to read that entire response. if you agreed with me then great. if not, i'll be passing you in the snow with my 4X4 engaged and locked.

                    Comment


                    • #25
                      To everyone that contributed... THANK YOU for your input.

                      This is what I have concluded from reading this thread...

                      1. it's ok to use 4hi up to a reasonable freeway speed

                      2. although ok, the highest speed that I'd ever use 4hi is probably 45-50mph, and even then, for short spurts, because if conditions do require 4hi, I wouldn't want to be going that fast anyway

                      3. as our 4hi locks the axles together(not side to side but front to back), there is no delay in tj 4x4 systems, as there is no reaction time, since we're hooked up to begin with.

                      4. and to whomever it is that said they don't use 4 wheel drive until necessary, i'm going to have to disagree with that, and here's why...
                      I lock into 4hi as soon as I hit unpaved road (even if it's something that can absolutely be done in 2wd) because the moment you step off of paved road surface, it is much easier to spin tires, lose traction, etc, which then tears up the road surface. however, if you're in 4hi, you're less likely to tear up the road, which is inevitable as you'll eventually get to a point where you'll need 4wd... and how do you figure that out? you'll start to lose traction in 2wd, and start spinning tires.

                      I expect a lot of you to disagree with me and call me a treehugger for that last statement. and that's ok, as it's all a matter of opinion anyway. for those of you who say why put the extra wear on your drivetrain? imho, the wear difference is extremely small, everything's spinning in oil anyway, and why the hell not? it's a small price to pay for huge advantages such as not being as hard on unpaved roads, which leads to other benefits as less runoff into waterways, less negative views of 4x4's, and maybe in an extreme case, it could help prevent closure of trails due to less impact on the trail surface.

                      Just my two cents.

                      Comment


                      • #26
                        one little FYI...you're supposed to drive in 4-wheel drive about once a month. this keeps the seals all lubed and working properly.

                        Comment


                        • #27
                          Originally posted by FUBAR
                          one little FYI...you're supposed to drive in 4-wheel drive about once a month. this keeps the seals all lubed and working properly.
                          With a vehicle that has lock out hubs..... Your showing your age!


                          Good summary!

                          Comment


                          • #28
                            I fail to see the need to know how fast you can go in 4-wheel-drive mode.
                            the whole point of the this thread was to determine when a jeep should be slowed back down to shift in or out of 4x4 or if it was acceptable to leave it in 4x4 at normal highway speeds. which has be determined yes it is ok to run at hi speeds but is reckless.

                            now that we are all educated on honda and subaru All Wheel Drive systems which have nothing to do with a part time four wheel drive system that i will say yes there can be a delay in a NP231 transfer case- when you jerk the lever forward the gears will need to get spinning,mesh and lock together and sometimes it can take time.

                            and if you are stuck and can't rock the vehicle back and forth to get the front axle engaged - what are you going to do?

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                            • #29
                              Originally posted by badtux
                              snip...
                              The net effect on the automatic transmission version of the Subaru system was that if you accelerated around a corner and the front end started slipping (what causes understeer in front-wheel-drive cars), the rear end would suddenly kick in and cause an oversteer situation. To say that this was exciting is an understatement. But the Jeep TJ's "part-time" system is nothing like this, so you don't have to worry about it with the Jeep TJ.
                              The Trac-Loc on my TJ has a funky notion of when to kick in, especially on mornings like yesterday when it is icy/snowy out... I stepped hard on the gas to pull out from a stop sign... only to cross the street and enter my travel lane going sideways...

                              after a couple of moments of panic, I got the front end pointed the correct way, but the adage about every Jeep being different certainly applies.
                              I don't think there is any substitute for getting to know your individual vehicle and how it behaves (or misbehaves as the case may be).

                              Comment


                              • #30
                                Originally posted by oros35
                                With a vehicle that has lock out hubs..... Your showing your age!

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