I read in the manual that Toyota recommends running the 4WD system once a month to keep things lubricated and from stiffening up. However they are pretty vague on how this is done and for us with the more basic 4WD systems this can be potentially harmful by running 4WD on the street. A wet street is a little less risky but still can cause binding.

Way back in the day I used to own a 98 Kia Sportage 4x4. In concept it was pretty cool and was amazing in the snow. However it road like crap and was way underpowered. Reliability was a question mark along with fit and finish. I did not keep it long. Anyways for the system on the Kia Sportage they recommend once a month putting it in 4WD on a flat and straight road with the front wheels straight until the 4WD light illuminates then when it does go back into 2WD. This procedure locks the front hubs and while you drive it turns the front differential and all hardware but its safe to drive on dry roads because the transfer case is not engaged. About the only bad thing is a minimal amount of wear on the 4WD components and slightly worse fuel economy from spinning the extra hardware. The front hubs remained engaged until you backed up for 5 feet or so.

Another interesting feature if I can remember is once the front hubs were engaged you can go in and out of 4WD at any speed. However to lock the front hubs you had to be going under 15 mph or you would mess up the hubs. Some people did it at much higher speeds and got away with it but 15 mph was the theoretical top speed. It was common on the Sportage to lock the front hubs in snowy roads and then go in and out as needed.

My question is does the system on the 4Runner work the same way? If I engage 4WD and the light comes on then disengage 4WD but continue to roll forward does it keep the hubs locked until you back up a certain distance?

If it does work the same way doing what I mentioned above might be a very affective way of keeping the 4WD system in good shape. Don't do it every day but once a month or so.

My 4Runner is a 98 SR5 with the more basic 4WD system. I understand the Limited's of certain years and later models had different systems.

I'm not familiar with the Kia set up, but from what you describe, it is not the same as the 4Runner. The part time 4wd system in the 4Runner is a little simpler. When you shift the transfer case lever into 4Hi, the transfer case engages the front drive shaft and sends power to the front diff. At the same time, the ADD (Automatic Differential Disconnect) system makes a connection between the front axles and the front diff. The ADD system operates independently from any axle rotation, so the system can engage and disengage while the vehicle is stationary. However sometimes a little forward or backward motion is needed to help the gears, shafts and sleeves to line up properly. Also, if my 4wd light does not come on while I am stationary, shifting into Neutral and then back in to Drive always gives it the little 'push' it needs. You can find plenty of info on ADD online if you want to know more details.

As far as the recommended periodic operation of the 4wd system goes, don't be too concerned about running it on dry pavement for a few seconds or so if that's your only option. A hundred yards is enough to spin everything, and certainly not enough to cause problems. Damage will only occur if you run it for miles and miles all the time.

Mine has the 4WD button on the tranfer case shift lever that you can push to engage 4WD without locking in the transfer case. This is primarly for driving on slick surfaces, like icy roads, but at higher speeds. This is all you need to do to lubricate the 4WD components. My user manual says you need to be going slower than 62 mph to engage or disengage this button. It is more like AWD you see on some other 4WD vehicles.

To get locking transfer case or lower ratio 4WD, you must move the transfer case shift lever.

Ray

The Kia system was mechanical in nature meaning when the 4WD was engaged the hubs would lock into place as power was applied to the system. They stayed locked until 4WD was disengaged and you backed up 5' or so. It was a pretty fragile system and you should (but could) engage 4WD at speeds 15 mph or less. Some people did it at higher speeds successfully but a few people managed to crunch the hubs by engaging at high speeds. One nice thing about the Kia system is once engaged as long as you did not back up you could go in and out of 4WD at any speeds up to 60 mph.

Sounds like the Toyota system works differently and will engage and disengage the hubs as the lever is moved. So engaging 4WD and then disengaging does not keep the hubs locked and the 4WD hardware spinning. I will research the Toyota ADD system firther to see how it works.

For my 4Runner every month or so I engage 4WD on a rainy straight road and drive as far as possible without turning the wheel much. Likely its sufficient to keep everything in order and more then most people do.

i do this about once a month as well but only in 4hi and not 4lo should i do 4 lo as well?

You do not need to operate in 4 low for the maintanance as being talked about. The purpose behind this to get the drive shafts spinning and that in turn keeps the seals and other parts lubricated. The gears for Hi or Lo are inside the same case so as the oil is being moved around it is getting all the gears. The manual actually calls for 10 miles a month. I do this and more in 4wd on the dirt now but before I would jsut engage 4Hi while on the fwy when I knew I had no turns coming up for a while.

I run mines for about 1.5 miles every month down a long dirt road in 4Hi. I probably should run it in 4wd more, but I think that's enough.

I just bought a used 1996 Limited and I'm not sure if 4Wd was EVER engaged... I don't want to run 4wd to lubricate if this thing has been bone dry for 10 yrs, ALL suggestions are welcome as this is my 1st truck

Just replace all fluids and see what happens. There's nothing about the system that you should be affraid of once it has good oils in it.

I wheel mine (using 4wd, Hi and Lo) and change the gear oil regularly.

If the transfer case was bone dry, it would lockup driving. Shift into 4Hi and 4Lo (read the manual for the proper procedure).

Also change all the fluids to prolong life.

I thought there was a burnt metal type smell after kicking it into 4WL, but that might have been from trying to shift while rolling...
I should dive into the repair manual before asking stupid questions, but the 2K pg repair manual is a bit daunting

You can shift in and out of 4Hi up to 50mph. You do need to be stopped and in neutral to go in and out of 4Lo. (unless you have a manual transmission, then you can shift out of 4Lo while moving)

I just bought a 96 Ltd, with the push button 4wd. As far as I can tell, the 4wd works fine, but has one glitch: when you push the button to disengage, the 4wd indicator light does not turn off - you need to briefly turn off the ignition, then it seems to reset and the light turns off. I need to get it off the ground to see if the 4wd actually disengages when you hit the button... but in the meantime any ideas would be much appreciated!