To full time all the time or not?

flman · **Posted:** Sat Sep 27, 2014 12:52 pm

It is kind of nice to run in FT on dry pavement, you can take off at intersection with no wheel spinning, and the Jeep feels more sure footed in turns.

Any pros or cons in using FT all the time?

thermorex · **Posted:** Sat Sep 27, 2014 3:17 pm

Other than wear and tear on the front driveline and a little worse mileage, I can't think of a reason.

flman · **Posted:** Sat Sep 27, 2014 4:25 pm

thermorex wrote:

Other than wear and tear on the front driveline and a little worse mileage, I can't think of a reason.

I thought all of that stuff is turning any ways, and it only kicks in during rear wheel spin? Maybe you will see a miniscule mileage gain and a little better tire wear in the back? Better to be moving forward on acceleration, then to be spinning your wheels going no where slow?

diesel_guy86 · **Posted:** Sat Sep 27, 2014 4:48 pm

There's a differential between the front and rear that allows them to be independent of each other. You can still spin only one axle when in full time 4wd. This should keep the drive train from getting any extra wear when driving down the road.

flash7210 · **Posted:** Sat Sep 27, 2014 5:10 pm

Without a doubt the KJ handles so much better in full time 4wd. I'm always amazed of how much better it corners. Especially on wet pavement.
However it will wear out your front tires faster. So be prepared for more frequent tire rotations.

65Corvair · **Posted:** Sat Sep 27, 2014 10:04 pm

I use full time, all the time once the snow start flying here, but I usually keep it in 2wd during normal driving. Though, I m not opposed to leaving it in 4-Full Time all the time.

thermorex · **Posted:** Sun Sep 28, 2014 2:01 am

I barely use it in the winter also, maybe bc I'm used to the Cherokee's command track... If it's less than 1/2 foot of snow and I don't go uphill, I don't bother, especially with the offroad tires I have. Regarding wear and tear, it will be more if 4wd is used since there is rotating force through the diff from the engine, can't say about tire wear, but it obvious it will be bigger than when not used. I honestly don't think wear and tear would be such a bid deal that would make somebody think twice before using it. Aggressive driving will wear the tires with or without front axle engaged. And yea, agree, on full time there isn't any "clutch" or electronic magic that connects the rear and front axle so if one slips, the other will get traction.

mass-hole · **Posted:** Sun Sep 28, 2014 2:30 pm

I use mine while towing or when it is raining or snowing. I tow every couple of weeks it seems so its engaged quite a bit. If its dry and I am just driving to work I usually leave it in 2wd.

papaindigo · **Posted:** Sun Sep 28, 2014 4:13 pm

I tend to use it when the streets are wet just because. I've had to use it once to get an idiot out of N FL beach sugar sand. That said it's probably a good idea to occasionally run thru all the 2/4 wheel positions just to make sure things can continue to move.

dgeist · **Posted:** Sun Sep 28, 2014 5:12 pm

I leave it in full-time basically full-time. The only time I take it out is if I NEED the tires to spin or I'm diagnosing something in the driveline... or if I put it in part-time or low range off-road. Handling is far superior. Traction is noticeably better in every condition (including dry pavement).

As for premature tire wear...seriously? If you are driving hard enough that having driven front wheels significantly shortens your rotation period vs rear-wheel only then you're not driving the right vehicle. Frankly, hard braking and turns on pavement does the most to wear tires than anything except a bad alignment. 5-tire rotation is the way to go at every oil change.

As for extra wear on the front driveline components...well...maybe so since there's a torque load on them instead of freewheeling, but then you can argue there's that much LESS in the rear, so out back wear will be DECREASED accordingly. I frankly think it's a wash but I like having all the moving parts moving and getting lubricated evenly instead of having certain joints go unused...until you need them.

Dan

mass-hole · **Posted:** Mon Sep 29, 2014 11:01 am

dgeist wrote:

I leave it in full-time basically full-time. The only time I take it out is if I NEED the tires to spin or I'm diagnosing something in the driveline... or if I put it in part-time or low range off-road. Handling is far superior. Traction is noticeably better in every condition (including dry pavement).

As for premature tire wear...seriously? If you are driving hard enough that having driven front wheels significantly shortens your rotation period vs rear-wheel only then you're not driving the right vehicle. Frankly, hard braking and turns on pavement does the most to wear tires than anything except a bad alignment. 5-tire rotation is the way to go at every oil change.

As for extra wear on the front driveline components...well...maybe so since there's a torque load on them instead of freewheeling, but then you can argue there's that much LESS in the rear, so out back wear will be DECREASED accordingly. I frankly think it's a wash but I like having all the moving parts moving and getting lubricated evenly instead of having certain joints go unused...until you need them.

Dan

The traction thing, i think, is especially critical on the CRD's where we can make a mountain of torque fairly quickly. If I come out of an intersection a little hard I can spin the rear tire really quick and then I am sitting there waiting for the ESP to "save" me as I am about to get T-boned. The full time keeps it from ever engaging ESP.

tjkj2002 · **Posted:** Tue Sep 30, 2014 4:09 pm

mass-hole wrote:

The traction thing, i think, is especially critical on the CRD's where we can make a mountain of torque fairly quickly. If I come out of an intersection a little hard I can spin the rear tire really quick and then I am sitting there waiting for the ESP to "save" me as I am about to get T-boned. The full time keeps it from ever engaging ESP.

Sounds more like you need better tires.

I can roast the rears on command with my 3.7 gas KJ that weighs 2000lbs(49%/51% weight split via weigh scale,so more rear weight) more then your CRD and with 35" tires,granted that's with Destination MT's.100% more traction when I bolt on my MT/R K's which are actually a little narrower then the Destinations(35x12.50x15 MT/R K's vs 315/75R16 Destinations).The MT/R's are also about 10lbs light per tire and the rims are about 6lbs lighter (15x8 vs 16x10).

flman · **Posted:** Tue Sep 30, 2014 4:48 pm

tjkj2002 wrote:

mass-hole wrote:

The traction thing, i think, is especially critical on the CRD's where we can make a mountain of torque fairly quickly. If I come out of an intersection a little hard I can spin the rear tire really quick and then I am sitting there waiting for the ESP to "save" me as I am about to get T-boned. The full time keeps it from ever engaging ESP.

Sounds more like you need better tires.

I can roast the rears on command with my 3.7 gas KJ that weighs 2000lbs(49%/51% weight split via weigh scale,so more rear weight) more then your CRD and with 35" tires,granted that's with Destination MT's.100% more traction when I bolt on my MT/R K's which are actually a little narrower then the Destinations(35x12.50x15 MT/R K's vs 315/75R16 Destinations).The MT/R's are also about 10lbs light per tire and the rims are about 6lbs lighter (15x8 vs 16x10).

LOL, we are not driving gassers, we are driving torquemonsters.

I have spun Michelins, Bridgestones, Wranglers with out even trying.

mass-hole · **Posted:** Tue Sep 30, 2014 4:57 pm

flman wrote:

tjkj2002 wrote:

mass-hole wrote:

The traction thing, i think, is especially critical on the CRD's where we can make a mountain of torque fairly quickly. If I come out of an intersection a little hard I can spin the rear tire really quick and then I am sitting there waiting for the ESP to "save" me as I am about to get T-boned. The full time keeps it from ever engaging ESP.

Sounds more like you need better tires.

I can roast the rears on command with my 3.7 gas KJ that weighs 2000lbs(49%/51% weight split via weigh scale,so more rear weight) more then your CRD and with 35" tires,granted that's with Destination MT's.100% more traction when I bolt on my MT/R K's which are actually a little narrower then the Destinations(35x12.50x15 MT/R K's vs 315/75R16 Destinations).The MT/R's are also about 10lbs light per tire and the rims are about 6lbs lighter (15x8 vs 16x10).

LOL, we are not driving gassers, we are driving torquemonsters.

I have spun Michelins, Bridgestones, Wranglers with out even trying.

It doesnt help that we have '06's without LSD's as useless as they may have been. I want a Tru-trac for at least the rear.

I am wondering how my snow tires will do. I remember my michelin x-ice having more traction on my lincoln LS V8 than the Nitto 555 summer tires I had.

SFHLibertyCRD · **Posted:** Tue Sep 30, 2014 7:19 pm

Dan, are your mileage numbers in Fuelly with full-time 4wd on most of the time?

dgeist wrote:

I leave it in full-time basically full-time. The only time I take it out is if I NEED the tires to spin or I'm diagnosing something in the driveline... or if I put it in part-time or low range off-road. Handling is far superior. Traction is noticeably better in every condition (including dry pavement).

As for premature tire wear...seriously? If you are driving hard enough that having driven front wheels significantly shortens your rotation period vs rear-wheel only then you're not driving the right vehicle. Frankly, hard braking and turns on pavement does the most to wear tires than anything except a bad alignment. 5-tire rotation is the way to go at every oil change.

As for extra wear on the front driveline components...well...maybe so since there's a torque load on them instead of freewheeling, but then you can argue there's that much LESS in the rear, so out back wear will be DECREASED accordingly. I frankly think it's a wash but I like having all the moving parts moving and getting lubricated evenly instead of having certain joints go unused...until you need them.

Dan

tjkj2002 · **Posted:** Tue Sep 30, 2014 7:24 pm

flman wrote:

LOL, we are not driving gassers, we are driving torquemonsters.

I have spun Michelins, Bridgestones, Wranglers with out even trying.

In hi range(2wd) starting from a dead stop my KJ is putting 3616lbs-ft of torque to the rear wheels,yours is putting 3301lbs-ft. Just saying :ROTFL:

thermorex · **Posted:** Tue Sep 30, 2014 9:54 pm

tjkj2002 wrote:

flman wrote:

LOL, we are not driving gassers, we are driving torquemonsters.

I have spun Michelins, Bridgestones, Wranglers with out even trying.

In hi range(2wd) starting from a dead stop my KJ is putting 3616lbs-ft of torque to the rear wheels,yours is putting 3301lbs-ft. Just saying :ROTFL:

According to Keith, the full torque Eco outs 335 with tc on lockup at flywheel, so at wheels it's probably about 20%less. Unless you put that hemi in yours, or did some serious mods, I don't think you get 360 at wheels (figured 3616 is a typo, unless you have a train tractor diesel engine on that bad boy, lol). But I do believe you can spin the wheels, I can do that on the Cherokee with 31 inch tires and still 3.55 Diff gear ratio. Btw, what gearing do you have for the 35 inch tires? 4.10 or lower?

tjkj2002 · **Posted:** Tue Sep 30, 2014 10:17 pm

thermorex wrote:

tjkj2002 wrote:

flman wrote:

LOL, we are not driving gassers, we are driving torquemonsters.

I have spun Michelins, Bridgestones, Wranglers with out even trying.

In hi range(2wd) starting from a dead stop my KJ is putting 3616lbs-ft of torque to the rear wheels,yours is putting 3301lbs-ft. Just saying :ROTFL:

According to Keith, the full torque Eco outs 335 with tc on lockup at flywheel, so at wheels it's probably about 20%less. Unless you put that hemi in yours, or did some serious mods, I don't think you get 360 at wheels (figured 3616 is a typo, unless you have a train tractor diesel engine on that bad boy, lol). But I do believe you can spin the wheels, I can do that on the Cherokee with 31 inch tires and still 3.55 Diff gear ratio. Btw, what gearing do you have for the 35 inch tires? 4.10 or lower?

Torque multiplication,1st gear ratio x diff gear ratio x engine torque rating.

Used the advertised torque #'s and I'm running 5.13 gears and have the same 3:1 1st gear since both the '02 KJ's and CRD's use the same trans.

flman · **Posted:** Wed Oct 01, 2014 6:51 am

tjkj2002 wrote:

flman wrote:

LOL, we are not driving gassers, we are driving torquemonsters.

I have spun Michelins, Bridgestones, Wranglers with out even trying.

In hi range(2wd) starting from a dead stop my KJ is putting 3616lbs-ft of torque to the rear wheels,yours is putting 3301lbs-ft. Just saying :ROTFL:

I am running the hot tune, and no gasser puts out its full torque under 2000 RPM. :goink:

Wind that sucker up if you want some torque. So you must be taking off pedal to the metal.

Either you can drive a CRD or just talk about them like you do.

mass-hole · **Posted:** Wed Oct 01, 2014 1:13 pm

flman wrote:

tjkj2002 wrote:

flman wrote:

LOL, we are not driving gassers, we are driving torquemonsters.

I have spun Michelins, Bridgestones, Wranglers with out even trying.

In hi range(2wd) starting from a dead stop my KJ is putting 3616lbs-ft of torque to the rear wheels,yours is putting 3301lbs-ft. Just saying :ROTFL:

I am running the hot tune, and no gasser puts out its full torque under 2000 RPM. :goink:

Wind that sucker up if you want some torque. So you must be taking off pedal to the metal.

Either you can drive a CRD or just talk about them like you do.

Since literally every CRD owner discussing in this thread has at least an ECO Tune(except for maybe 1 person) if not a Hot Tune or stage 2 Turbo:

Stg 2 Turbo CRD - 400 ft-lbs X 3:1 1st gear x 3.73:1 FD = 4476 ft-lbs.
Hot Tune CRD - 370 ft-lbs X 3:1 1st gear x 3.73:1 FD = 4140.3 ft-lbs.
EcoTune CRD - 335 ft-lbs X 3:1 1st gear x 3.73:1 FD = 3748.7 ft-lbs.

All of these trq numbers are peaking @ 2000rpm with only slightly less at 1600rpm. That's recipe for wheel spin and why full-time 4wd does help us CRDers out substantially.

To full time all the time or not?

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