Rough Shifts in 4LO

Decided to spend some more time messing around in 4wd the other day. My Taco is my first 4x4 vehicle so I am still learning.

As I was driving around some nearby grasslands, I had the truck in 4LO without the diff locked. After I hit a straight section, my truck went to grab the next gear and the shift was NOT smooth at all (Automatic, 1st to 2nd). It was a jerking motion that did not feel comfortable. I repeated this a few more times just to be certain.

I understand that 4LO is mainly for slow, technical situations where you need extra torque. Are these jerky shifts normal?

 

Mine does it too, it's usually higher in the gears though, like 2 to 3 or 3 to 4, 1 to 2 is usually smoothish but still rougher than 2h or 4h.

 

Read your manual.

 

It's because in 4LO there is a massive amount of torque being applied through the drivetrain so everything is felt in an amplified manner.

 

4lo is a slow gear. If you want to get faster speed switch to 4hi.

 

How fast were you going?

 

Ok, that is what I thought. Best practice to switch back and forth I suppose.

I was not paying enough attention but it was steady acceleration up to around 1700-2k to prompt the trans to grab the next gear in 4LO. I decided to leave it in low gearing since I was going to come up on a slower section again.

 

Your transmission sucks in 2hi. Putting it into 4lo only intensifies the effect.

 

As other people said, its mostly likely just the gear reduction (aka more torque) so you feel it more. If you keep going faster you should feel about the same up into 3rd and 4th gears.

Im not sure about 3rd gens, but I know in 2nd gen ATs the computers prevent torque converter lock-up and keep the truck out of 5th gear in 4Lo. Id imagine the same is true of the 3rd gens. Probably can get up to 4th gear in 4Lo. So you can easily get up 30-40mph if you really want to

 

This is horrible advice. If you attempt to get up to 40mph in 4lo, you’re going to destroy your torque converter lol. 4lo should be limited to 1st gear and used for slow crawling

 

I think I read in the manual you can get up to 50mph in emergency situations in 4LO. Obviously I completely agree with you but I just wanted to share that fun fact.

 

Wait.....

What?

 

Why? How will that "destroy your torque converter"? Like I said, the ECU/TCU keeps the TC from locking up in 4Lo and also keeps the trans out of overdrive (gears 1-4 in the 2nd gens).

If going 40mph in 4Lo was going to destroy something, I think they would have limited it even more to prevent that...

And for the record, Im not saying you should go 30-40mph in 4Lo, Im saying you can. OP wants to know what his truck can do and how it feels, I think going more than 5mph is good advice

 

4LO for slow technical sections and then switch to 4HI if you encounter a smoother/straight section of trail?

 

Without any snark I say this:

I would highly recommend joining a group that has weekend off road safety and "Academy" classes.

 

Please show us where the manual says this.

Thanks in advance.

 

No offense taken, I am definitely open to that. My experience has been limited to just go-fast cars and "off the public street" events.

 

Page 208 shows maximum allowable speed. It's actually 58 mph!

 

FYI

 

My truck doesnt allow for a shift into 5th in 4L.