My truck came with 4lo!

[simple]

My complete and utter lack of knowledge in off-roading should have been easily detectable in the title of this thread. Still, I figure I might as well ask my question to people in the know under the cover of anonymity the internet provides.

I was reading my manual a while back, and I know you have to put your truck in neutral at a dead stop to shift into 4lo, and I know the differential lock locks the...the...well, the differential to make all the tires spin at the same rate. But besides getting out of stuck mud, when is it appropriate for this (and is it necessarily bad for the truck to use it on paved roads just to try it?)?

Well, I put my truck into 4lo today about a block from my house thinking I could drive it there through my neighborhood just to get things a little lubricated. I shifted it into low gear, 2,3, and then 4th gear respectively until I got stuck in the middle of a cross street roughly 20 feet from where I switched back. My truck felt like the gears were catching and it would jerk. What am I doing wrong? Do you have to drive a special way or in a special gear for 4lo? And what situations would 4lo be good for... Just off-roading, right?

Respectfully,

somebody who hacked simple's, an incredibly knowledgeable and badass user's, account to ask this ridiculously stupid question.

 

[JB.]

..My truck felt like the gears were catching and it would jerk. What am I doing wrong? Do you have to drive a special way or in a special gear for 4lo? And what situations would 4lo be good for... Just off-roading, right?

Sounds like you had the center differential locked. If you do that on pavement, the truck will feel fine until you try to turn. The sharper the turn and the lower the speed, the more the truck will feel like it's locking up. The wheels are all forced to turn at the same speed, but in a turn, they all want to turn at slightly different speeds. If you didn't have the center diff locked, the jerking would simply be from the extreme amount of torque in low range that makes it hard to finesse the gas pedal and can make for some powerful gear shifts.

4 lo
Center locked: The toughest of slow speed, off-road conditions where you want/need the highest traction abilities.
Center unlocked: Contrasted with the above by somewhat easier terrain and/or you want turning ability without scrubbing the tires.

4 hi
Center locked: Higher speed off-road or slippery conditions. Only in severe, short-term cases would you use this on road.
Center unlocked: Normal road conditions where you desire 4WD drive (all wheel drive) for whatever reason.

 

[sharp4runr]

Also remember that in 4LO, you are limited to about 35mph because of the gearing. The lower gear puts more power to the wheels at slower speeds and is great for crawling or descending (engine braking helps a lot).

 

[simple]

Good lookin out. Very helpful, thanks!

 

[Falls]

JB hit the nut right on the head. One of the cool features of this truck is being able to use 4lo without being locked if need be when you just need the slow crawling gearing for something.