Posted: 4/20/2013 3:05:44 PM EDT
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The owner's manual for my 08 Tacoma states that 4WD models should be driven at least 14 miles/month with the 4WD engaged. During most of the past five years this was usually not an issue because I spent a lot of time working with seismic crews and got off the road often and frequently needed 4WD. I retired early this year and spend most of my time in and around Houston. I expect to get off road every so often in the future and really like this truck but I think I need a plan to keep the transfer case happy.
I have never seen the insides of a transfer case and don't know much about them but I assume there are gears, bearings, and seals in there that only get lubricant circulation or exposure when the 4WD is engaged. My current method is to take advantage of a stretch of road near my home I use often. It is paved but dead straight for about a mile. When I drive that stretch of road I engage the 4WD until I'm near the end where I have to make a 90 degree turn. This truck has an electrically engaged 4WD, some kind of solenoid actuator I guess. It also has a 4Lo setting that changes the ratios drastically. Engaging 4Lo involves engaging 4WD, stopping and putting the transmission in neutral, then rotating the switch to 4Lo I have climbed up some really steep mesas and never needed it but I have used it to go down them where I would probably die if the brakes failed. Is this a good plan? Is it ok to engage 4WD on pavement on a very straight road? Is about a mile occasionally enough? Do I need to go into 4Lo occasionally? |
| i rode back from the farm in my z71 in 4hi yesterday. only about 65 miles with more than half on the interstate. wondered what the grinding sound was when i pulled into the driveway....straight pavement wont be an issue. just dont put it in 4lo on pavement. ive seen the insides of several transfer cases. they get lubrication all the time. |
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yeah, don't do any tight turns and you will be OK. DO NOT PUT IN 4LOW ON PAVEMENT.
If you take tight turns, you will fuck your gears up. and you are right about 4low. great for going down hills. great for controlling speed when you want to crawl. great for steep ass hills. you don't want to have too much traction when you put a truck in 4 low. you need the front wheels to be able to slide around a bit to compensate for the interior turning wheel (if you made a right turn, this would be the front passenger tire) rotating less than the outside front wheel due to varying distances of travel for each wheel around the arc (the outside wheel will turn more revolutions than the inside wheel. Connect those 2 wheels with a steel rod, and the outside wheel is going to turn too slowly to match the "speed" of the truck......so you need things to be slick to accomidate this. (this also happens in 4 high, but the gearing isn't as extreme), and why you should use a straight piece of road. If you don't, and you make a tight turn, you will hear a loud popping sound. That's bad. |
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Thanks for the replies folks. Your insight is much appreciated.
I don't know much about an ADD actuator but the comment got me to thinking and it occurred to me that engaging 4Lo must involve another electric actuator. I have not had occasion to use 4Lo in a couple of years so I got a bit nervous about it. Last year after a long stretch of work that was on road only I realized that I had not engaged 4WD in months. When I did so it was very balky about going into and out of 4WD the first few times but after a bit of cycling in and out it worked normally and still does. Yesterday I found a straight stretch of parking lot where I could stop and engage 4Lo a few times. It sounded a bit more clunky than I remember but it worked fine. |
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I'm going to differ from the crowd here and say that exercising 4wd is not that important on most modern pickups. Most (but not all) modern pickups do not have disconnecting hubs, meaning the differential guts and most of the transfer case guts are always spinning as the vehicle is driven down the road. Most older pickups with disconnecting hubs had all of those parts stationary while driving, meaning seals and parts aren't being lubricated at regular intervals which is why exercising 4wd was important.
I don't know if a Tacoma has disconnecting hubs or not. A way to check is to see if you can spin the front drive shaft or not when the transmission is in park and transfer case is in 2wd. If you don't disconnecting hubs (meaning you can't turn the drive shaft), I would say you only need to put the truck in 4wd once and awhile to keep the actuator from freezing up and you should be good. You really don't have a need to drive more than a block in 4wd to exercise everything. If you do have disconnecting hubs, I would try to find a gravel road and just drive a couple of miles in 4wd to keep things lubricated. I also like the idea of doing it on a rainy day if you don't have a gravel road near you. |
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Quoted:
4low on pavement is a rumor. They make cars for the common idiot you know. Hard on tires but you are not going to break gears driving on pavement. Driving in 4wd hi or low on high traction surfaces is still very hard on 4wd drivetrain parts. You probably won't have an immediate failure but weak parts like CV axles will wear out quicker. |
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Quoted:
Thanks for the replies folks. Your insight is much appreciated. I don't know much about an ADD actuator but the comment got me to thinking and it occurred to me that engaging 4Lo must involve another electric actuator. I have not had occasion to use 4Lo in a couple of years so I got a bit nervous about it. Last year after a long stretch of work that was on road only I realized that I had not engaged 4WD in months. When I did so it was very balky about going into and out of 4WD the first few times but after a bit of cycling in and out it worked normally and still does. Yesterday I found a straight stretch of parking lot where I could stop and engage 4Lo a few times. It sounded a bit more clunky than I remember but it worked fine. Engaging 4low uses the same actuator as 2hi to 4hi. If you search Google for fj add replacement, you should get a link to a very good writeup on the FJ forum which has pictures and descriptions of all of the parts involved. |
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Quoted:
4low on pavement is a rumor. They make cars for the common idiot you know. Hard on tires but you are not going to break gears driving on pavement. I drive on slick rock all of the time in 4low, with more traction than any pavement, often making many point turns on switchbacks. My tires howl and scream like hell, but nothing has ever broke. |
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Quoted:
I'm going to differ from the crowd here and say that exercising 4wd is not that important on most modern pickups. Most (but not all) modern pickups do not have disconnecting hubs, meaning the differential guts and most of the transfer case guts are always spinning as the vehicle is driven down the road. Most older pickups with disconnecting hubs had all of those parts stationary while driving, meaning seals and parts aren't being lubricated at regular intervals which is why exercising 4wd was important. I don't know if a Tacoma has disconnecting hubs or not. A way to check is to see if you can spin the front drive shaft or not when the transmission is in park and transfer case is in 2wd. If you don't disconnecting hubs (meaning you can't turn the drive shaft), I would say you only need to put the truck in 4wd once and awhile to keep the actuator from freezing up and you should be good. You really don't have a need to drive more than a block in 4wd to exercise everything. If you do have disconnecting hubs, I would try to find a gravel road and just drive a couple of miles in 4wd to keep things lubricated. I also like the idea of doing it on a rainy day if you don't have a gravel road near you. All part time 4wd Toyotas have add to disconnect the front axle. The actuator in it, the transfer case, and the diff locks need to be used regularly to ensure trouble free operation when they are needed. |
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This topic cracks me up.
When I wheel, I am in 4LOW all day, hours and hours and (miles and miles?) :) Im looking for the line with the most traction and trying to make every little steering correction to maintain my 'line', so sharp turns in 4LOW with 100% traction is a common occurrence Would I suggest rolling around on blacktop and concrete in 4x4 on a daily basis? No. Why would you? Common sense says you will wear more parts, and tires. I use 4HI in the rain on my 1/2 ton, keeps the rear wheels from spinning should I need to make a hasty movement (pulling out, switching lanes, etc) Bottom line is this...I don't think it really hurts em |