Keeping 4wd healthy - regular use of 4WD

I engage 4Hi almost daily and 4lo and locked usually once a week.

 

Every time you go on the pavement or off-roading? I wouldn't do it everyday, just once a month and I don't think 4lo is really necessary.

 

4lo/locked is strictly off-road or gravel use only, I hit 4hi so I don't tear up the gravel hill driveway I live on

 

Ok I'd like to be the guy helping this time instead of the one being helped, or at least hope I'm helping. Then again maybe im getting a little cocky seeing as I'm a pro now with my Tacoma after only owning it since May ( that was sarcasm). Anyway the first few times I exersized the locking differential it took a painfully long time, but each time I did it on a short flat STRAIGHT piece of pavement it got quicker and quicker. Well tonight I did it when I got off work. I kid you not it kicked in almost immediately when I did it about four times. So anyone that is new to the Tacoma way of using the locking differential ( I had an automatic Eaton differential in my GMC) I hope this helps

 

It's always good to turn your rear diff on and leave it on for a few hundred feet. Mine came on immediately as well when I needed it to climb up this hill.

 

Can the 10 miles a month be all in 4 hi? Or do we need to run 4 low, too?

 

I've been driving 4X4's since the 1970's, here is my advice and some personal experiences. You can get away with operating in 4X4 on straight stretches of pavement for short distances. I've done so on a few occasions when I needed lo range to back trailers uphill when using manual transmissions. Not that I needed 4X4, but the control of lo range was helpful.

I strongly advise against using 4X4 even on wet pavement, especially at highway speeds. An all wheel drive car will allow all 4 wheels to travel at 4 different speeds and still have power to all 4 wheels. A 4X4 vehicle will force all 4 wheels to turn at the same speed as you corner. There is simply no way to do that unless the inside wheels slip or spin on the ground since they are traveling less distance than the outside wheels. At slow speeds, on loose or wet ground this isn't a problem. On dry pavement you can damage components. At high speeds on wet pavement you are forcing the inside wheels to lose traction on curves Not what you want, you'd get BETTER traction in this case in 2wd.

It doesn't take much driving on pavement in 4X4 to do major damage. One of my early 4X4's was a 1975 Jeep J-10 truck that used AWD most of the time, but could be locked into true 4X4. I bought it used and had to have the transfer case rebuilt twice in 3 months. During the 2nd rebuild it was discovered that the vacuum lines used to engage true 4X4 had at some point been reversed. I was driving in 4X4 all the time even though the selector switch said I was in AWD. I was young and inexperienced, I'd pick up on that pretty quick today.

I do recommend shifting into 4X4 as much as possible, but only off road or on a gravel or dirt road. I may not get the recommended 10 miles every month, but any time I'm on a gravel or dirt road I shift into 4X4 for a few miles. I shift into low range and lock the rear axle at the same time for at least a short time.

I did have a 1991 Cherokee refuse to shift into 4X4 once after it had not been used for an extended period of time. The locking hubs used air pressure from vacuum lines to slide on a shaft in order to lock the hubs. Due to lack of use the grease on the shaft had gotten hard and there wasn't enough air pressure to lock them. It was a simple fix, just clean and re-lubricate. But I had to use some driving skills and spin some tires to get out of a spot in 2wd that would have been very easy If I could have gotten it into 4X4.