4Lo Power

Last night I used my truck to pull out my stuck tractor so I hooked up to it using front tow hook and put it in 4Lo and proceeded to reverse. It pulled with the torque I expected at first, but as I mashed the throttle the engine seemed to bog down and would not rev as the tires began to slip. Is this normal? I guess in the 8 years of Tundra ownership, and having to use 4Lo a few times, I've never experienced that. I was able to unstick the tractor (of course), but it didnt seem to do it right, if that makes sense.

 

Sounds like the nannies/traction control may have been on. Still really don't want to rev your engine too high with 4LO engaged

 

It's ties like that (the OP) that you reeeeeeeeeeeeeeaaallly want a 3 floor pedal set up.

 

Yes that is normal. It's your traction control system kicking in. It applies the brake to the slipping wheel and cuts power.

 

Just a heads up, you should never pull backwards. Always forward.

 

I usually don’t, but it was much easier access and I wasn’t putting a huge load on the truck. Just enough to help the tractor get back to some traction.

 

All traction control is off in 4lo, is it not? It wasnt acting like traction control. The engine just was bogging down.

 

Wouldn’t the nanny stuff be off in 4 low? Haven’t used 4 low in my truck at all. So far.

 

Its already hard on a transmission to go into reverse. So even harder for you to pull in reverse. It’s the way it spins and gearing and how the trans actually rotated on reverse to put things simply. I’ve rebuilt a lot of transmissions (not for this reason per say) but I would advise against pulling in reverse. Front tow hooks are for you to get pulled. And that being said. Don’t pull using the ball on the hitch. They make d ring hitch adapters.

 

When I put my truck in 4 low, all the traction stuff shuts off.

Are you sure you were in "4 low" and not just in 4 high with the 4 low flashing (not engaging it in neutral)?

 

Yes it was in 4lo and all traction control was off.

I think the best explanation is the fact I was in reverse which isn’t geared the same.

 

I don't know if mine works properly or not in 4lo. I've always thought 4lo was supposed to be high torque. I know in my work Chevy 4lo is a damn champ! Then I used 4lo in my tundra one day and it like barely does anything and revs high. Yes traction control is fully off and 4hi works normal although not a fan of the open diff. Chevys 4x4 is better.

 

Does it have ATRAC?

 

It's not necessarily the traction control cutting power in 4Lo. The stock tuning limits throttle opening in 4Lo to protect components from getting destroyed. I'll have to look back at my stock tune file for specifics, but basically at 800 RPM, the ECU allows 86 degrees of throttle opening (86* = 100% throttle). At 1100 RPM, it limits you to something like 46*, and above that 30-something* throttle opening. So, yes, your experience mimics the limits and protections built in to the stock tune.

Aftermarket tuning can increase or remove those limits entirely. Look up ViktorG tuning or HP Tuners on the site if you would like more information on the subject.

The truck has WAY more power than is available to the end user at certain speeds and drive modes using a stock tune. But that stock tune is how we can get a million miles out of the truck without breaking stuff. So proceed at your own risk. Most of the supercharged guys remove the 1st gear and 4Lo limits on day one...

Also, one more voice in cautioning against pulling backwards. To add, the gears in the rear diff are weaker in reverse and it puts more load on the front drivetrain. But we've all done it. I've done it plenty with other vehicles. But it didn't always turn out pretty (blew a double cardon joint on vehicle, a hub on another...