is it ok to drive on wet pavement in 4wd with a np231

 

I wouldn't recommend it. There is no differentiating action while in part time 4wd.

 

x2. Just out of curiousity, why would you need 4wd on wet pavement?

 

Depends on just how wet the pavement is - but generally, no. Save the 4WD (since it's part-time) for when you've got snow, ice, mud, or other crap like that to deal with.

And - never forget that "four-wheel drive" != "four-wheel stop." You'll still need to think ahead while you're moving...

 

I wouldn't do it. Besides the unnecessary tire scrub (rapid tire wear) it is an additional strain on the transfer case. Your best bet would be running your TC during slippery conditions such as loose gravel,mud and snow. Rain in itself is not 'slippery' unless your tires have no thread...

 

Back in the 70s and earlier there were lots of full time trucks. They had full time transfer cases and factory drive flanges on the front axles. Not that they probably got good fuel mileage, and the parts wore out faster but its not the worst thing ever unless you have aggressive lockers front and or rear. What happened to your t-case?

 

i was just wondering because i seem to slide on wet pavement when it rains

 

Well there's two issues possibly: 1. Lay off the right pedal lol or 2. check your tires for wear bar indicators and see how much tread you have.

 

x2

 

True - but "full time" 4WD has differentiation action in the transfer case. The NP231 doesn't have a "full time" mode - it's only got a "part time" mode, which locks 52/48 (front bias.) This is why running a PT4WD when you have good traction, on a flat surface, usually ends up grenading the thing - that front bias (which is what you want in the slick - makes it easier to get your feet back under you if you lose gription) will eventually bind something up if you don't have any allowed slip. FT4WD is a differentiated 50/50 bias, which generally works akin to an LSD (bias will shift toward whichever end isn't slipping, if something decides to head West on you...)

 

well its kinda hard to stay off the pedal with a manual. My tires have more than 50% left on them. I think it may be just the tires its been like that since i first got them

 

Is this your first manual transmission vehicle? I'm asking because an experienced driver with a standard transmission has no issues staying out of the gas when taking off. (MOST of the time) Some tires are weird like that - they have issues on wet pavement. What tires are you running? I'm running Cooper Discoverer ATR's, and have no problems at all on wet, snowy, icy or dry surfaces.

 

The np242 has a 48/52 split just like the 231.
The split is given by the difference in gear ratio at the chain and is a built in characteristic.
When in FT, the split can theorically vary from 0/100 to 100/0 depending on the traction conditions. On dry pavement, the variation is very dependable from tire size/inflation, turns and acceleration of the vehicle. In an ideal case of perfect round tires with the same diameter, flat pavement and constant velocity the split average will be around 50/50, but that is an ideal case. In the reality, acceleration causes the mass center to move to the rear of the vehicle, and the rear tires tend to squat reducing their diameter. This happens also when towing a trailer or when you load the trunk. In terms of split this means an average of 48/52 also when driving at constant speed and on flat surfaces.

 

Ah - so the bias is still the same with the FT transfer case, it's just the LS differential that allows the bias to change PRN. Makes sense.

 

The NP203 used in many 70s GM trucks offered no slip or differential action. The only way to allow that would be installing a conversion kit with spider gears in the case and or lockout hubs. This did not grenade the t-case just wore parts out faster. The NP231 is not as stout of a case though.