5th Gen 4Runner maintance

How does the adage go? Complexity is the enemy of reliability. And many of us claim to eschew complexity, but we don’t really. A straight-six has fewer parts than a V6. Locking hubs are more reliable than the ADD. Live axle is simpler than independent suspension. Proactive 4WD systems are simpler than reactive AWD systems …

 

My '76 Nova had a straight six. What a pain that car was! I constantly had to clean the carburetor and adjust the timing. It ate mufflers one after another. The front ball joints failed, the leaf springs broke, it was just one thing after another. I managed to keep it going to ~170k miles. Cars were easier to fix back then, but they needed a lot more of it.

 

Perhaps some factor came into play other that it was an inline six. ;-)

 

One of these links happens to cite the great, wise and powerful @Captain Spalding

 

Evening all, I want to make certain I’m understanding what is being said. I have a 2020 Limited, which I never take off road. So, do I every month find a straight road, switch the knob to 4H and drive in a straight line for a few mins/miles? I then stop, switch it back and drive normal? Yes? Thanks

 

Quite so. Its fault was being a typical car from an era most fondly remembered by people who weren't born yet.

 

Not exactly. Your Limited has full time 4WD. So normally you are driving in H4F. That’s 4Hi with an open differential. So you are always driving in 4H. You can drive in H4F on dry pavement, wet pavement, snow, dirt, mud — anything. No limitations or caveats. When you push the lock button on the knob and rotate it to the H4L position you’re still in 4Hi but now the center differential is locked. That should only be done, according to the manual, on a loose or slippery surface so that stresses don’t build up in the propellor shafts. Many of us will, perhaps controversially, “exercise” our 4WD on dry pavement if we have a stretch of straight road, because the stresses build up more/faster when turning than when driving in a straight line. You can shift from H4F to H4L while moving at any speed. When you turn the knob to L4L now you are in 4Lo with the differential locked. To do that you need to come to a stop, foot on brake, put the gear shift into neutral, and then turn the knob. When you want to go from low range back to high range you must follow the same procedure. Stop. Foot on brake. Neutral. Turn knob.

The knob is an electric switch and is not mechanically connected to the differential. The actual shifting is done by an electric actuator bolted to the back of the transfer case underneath the car. This is the part you’re exercising. So when you exercise it you want to spend some time in both H4L and L4L, perhaps shifting among all three settings multiple times. See your owners manual for other warnings and caveats.

Edited to add: I referred to the actuator as “electric” instead of electronic because it’s pretty stupid. If you pull into your driveway in H4L, turn the knob to H4F, and then immediately shut the car off before the actuator completes its operation, it might forget what part of the process it stopped at and screw things up. So just wait until the light goes out on the dash before shutting the car off.

 

Holy crap!

 

How is blowing up a center diff any different than blowing up a part time tcase? Both will leave you stranded.

Both full-time and part time transfercases can be gear driven or chain driven. They can manually, electronically, or automatically actuated. I believe both part time and full time toyota transfer cases in the 5th gen are chain driven. Both are capable of being locked to a front/rear split.

A big difference between the two systems comes down to the front diff. The part time system has an actuator to engage the front diff when the tcase is put into 4wd. With the full time system the front diff is always engaged.

They both have similar style parts and they both have pros and cons. One has a simple tcase and complex front diff while the other has a complex tcase and a more simple front diff.

I'd prefer to have the part time tcase and a simple front diff. My chevy has manual locking front hubs that stay locked for the duration of winter so I can shift into 4wd when needed without having to worry about engaging the front axle.

 

I don't think it would be any different - you'd be camping out in both situations. I was replying to an earlier post that suggested that one of the advantages of the PT 4WD system, if off-roading in remote areas, is that it is just a less complicated system. I wasn't necessarily comparing blowing up a center diff/transfer case in a FT 4WD to blowing up a transfer case in a PT 4WD. Intent was to point out, out you also do, that the center diff/transfer case in a FT 4WD is more complex. Since the PT 4WD has the capability of operating in 2WD, and the FT 4WD does not, the idea was that there could be situations where if something breaks it could be possible/easier to restore 2WD in a PT 4WD such that you could at least limp home. I'm a mechanical engineer, and I am certainly no expert on 4WD systems, but the concept of going with a less complicated system to avoid potential problems makes some sense.

 

A locked center diff in the full-time 4wd 4runner is effectively the same as a part-time case in 4wd. You could drive both out in 2wd.

 

The No! No! No! light will come on if you do anything wrong.