Disable 4lo throttle limit

I recently discovered that when you put the truck in 4lo it reduces throttle response. I’ve always thought that 4lo was the “crawl or push through anything” switch but I have experienced several times where the truck just won’t go when in 4lo. I had attributed this to high altitude or a traction control nanny, but I’m thinking that’s not entirely the case. The truck won’t even rev up, just falls completely on its face. I plan on installing new 5.29 gears this year and will possibly install lockers while I’m at it. I want to make sure all that money isn’t wasted on a setup that won’t get up and over obstacles any better than it will now because of a stupid electronic control.

I hear this can be disabled (somewhat) via some tuning.

I know @Cruzer and @snivilous have some valuable knowledge on how to work around this. I’m sure there are others with good info, too. I’ve read Cruz’s thread and I’m not looking to go nearly as far as he did, just want a reasonable increase in low gear climbing/obstacle negotiation.

what’s the scoop?!

 

Here is a screenshot from HP Tuners of the torque/throttle limits. All the values shown are the max allowable throttle angle. Full opening is ~86deg. As you can see, the torque limits (big tables) already have lower than 86deg for a lot of the requested torque (effectively desired throttle) range. But there is also a 4Lo 1st gear specific table, in the bottom left, which as you can see allows full throttle opening but essentially only at idle, anything above that and it completely cuts the allowable throttle opening down to only 29deg.



It is standard practice in the tune to open up the maximum allowable throttle range by just increasing everything to 86deg:



But to reiterate, my understanding (I do NOT have direct experience) is that even maxing all the limit tables does NOT fully unlock the throttle---there are additional tables/values that we cannot access that limit allowable torque/throttle.

Opening up the throttle limits as shown above MAY be helpful, if you figure stock is like 20% available torque, and tuned is 60% available torque (making numbers up here), and the offroading you do only needs 55% available torque then you're home free! But not all offroading is the same, trying to climb a vertical ledge (or worse, an undercut) needs drastically different torque requirements than a 60deg inclined rock for example. This is why I say I don't have direct experience, I have taken my Tundra through lots of offroading and over some slick rock climbs that your "average" person would think are gnarly---but compared to other offroad stuff, that wouldn't even be considered an obstacle. I don't wheel my Tundra hard enough where I've had issue with maxed out (tuned) torque limits. My point just being, your mileage may vary, and what you need greatly depends on the person, truck setup, and terrain.

 

That is really helpful, thank you!

I guess the first thing that I need to do is check with OTT and see if their tune resets the throttle settings for 4lo.

 

Out of curiosity, what was the situation where you need more throttle in 4lo?

 

This is a great question. I was in 2 situations last year where this occurred.

One was a somewhat steep climb where the road was a mix of wash out/bedrock/loose dirt & gravel. I tried negotiating the route with 4hi and 4lo. 4lo fell on its face due to the throttle limits. 4hi was too fast, plus the traction control/open diffs were causing problems as articulating. It wasnt some ultra hairy/scary climb, just a bit too much for the truck to get up without really smashing up through it, which I try to avoid. I had all the kids and my wife with me that day and they weren't keen on smashing up so we hiked from that spot.

The other situation was a somewhat steep incline immediately following a tight switchback on Red Cone pass, if you're familiar with it. The road here is dirt, and it was mostly dry with a few muddy patches/holes. Partway up this steep section (probably only 30-40 feet long) there are some deep, offset holes (big enough to swallow most of a 35" tire). Here again, the 4lo throttle limit made the truck just fall on its face and didnt have the "oomph" to crawl up. 4hi I had to try about 15 times, but was finally able to smash up through it. It's the sort of obstacle that puts vehicles without really long travel on 3 wheels so the traction control and open diff were a big disadvantage. Again, nothing TOO crazy, just too much for the stock diff/traction/gearing/torque outputs for a stock Tundra to easily navigate. Here's a video of a Ram TRX negotiating the exact same obstacle last year, under the exact same trail conditions I encountered. This video gives good perspective because a couple modded gladiators go through, a TRX, and a couple mostly stock Cherokees. https://www.youtube.com/watch?app=desktop&v=eSkFq4RWFls

I'm on 35's, aired down. ADS/Deaver suspension. I'm pretty comfortable with off-road driving. I just feel like it shouldn't be so easy to stop this truck and the 4lo nannies are pissing me off.

 

@snivilous My first response this morning wasn't nearly long enough to address the helpful info you gave me. Thanks for being so thorough in your explanation! It elaborates on the other comment you made in my thread about 5.29's, which is what got me thinking about starting this thread specifically. I know these 4lo throttle limits came up tangentially in @Cruzer 's thread in his quest for the ultimate Tundra crawler, but I hadn't seen a thread specifically dedicated to this. Maybe I missed it somewhere?

I can't believe more people aren't encountering this problem as they wheel their trucks. Between the open diffs and the throttle nannies it's like Toyota didnt want this thing off the gravel!

Assuming a tune would allow the throttle to open further and provide more torque in 4lo (like in your hypothetical 20%-->60% increase) do you think the added torque would cause problems with breaking CV's and stuff? I'm sure Toyota did this as a measure to keep parts from getting over torqued, but are they THAT fragile?

 

To be frank I don't think most people offroading their Tundra push it hard enough to encounter any problems. Your basic trails in Moab I doubt you have issue with allowable torque, you're going to run into clearance issues long before that I suspect. For example, the approach angle is so bad you really can't run into something that requires that much torque to begin with. This is why the only people you hear about having issues (that increasing the torque limits doesn't fix) have very modified rigs, and there's just not a lot of those in general let alone on a forum primarily focused on stock or stock+ type vehicles.

I can't speak to the fragility of the platform since I don't really use my truck offroad, let alone have never broken anything in the manner you're referring. I will say, I hate having the vehicle make choices for me. Even if I'm never crawling gnarly shit, I'd prefer to have as much decision making in my own hands as possible. I'd rather have the option to risk breaking the CVs, versus that option taken away and just have to accept what the truck will allow me to do.


If you do flash your truck, keep in mind it's not cheap. It will run you $600 realistically, unless you can find someone local with the HP Tuners hardware (I go to Boulder occasionally, so could always meet you). Even if you find someone with the hardware it's still $200 just to unlock the truck. Now if you were already thinking of getting a tune from OTT then you can kill two birds with one stone, get the tune you want plus get the torque limits as lifted as possible. There is also VF Tuner, which seems to have more access to the trucks systems, but whether there's more access to the torque limits to truly turn them off I do not know---that option would cost similar to flashing with HP Tuners too.

 

Yea, I've already got the OTT tune on the truck. I just need to verify with them if their tune addresses the 4lo throttle limits. When I got that tune I had no idea this lack of 4lo power would be a thing for me. Perhaps if they didnt address it on the original tune they'll add it for me since I already bought it.

I've been reading the other threads on this issue, as well. (didnt mean to start a new one, I just hadn't seen the others) Sounds like everyone is experiencing the same stuff I have described. It's a disappointing flaw of an otherwise great truck.

It's such a subjective thing to compare my experiences with someone else's, but it does seem that 5.29's help A LOT with this issue. I'd hate to dump the money on a regear and locker, just to be disappointed that I still get stopped by Mickey Mouse obstacles. I dont plan to do @Cruzer or @Spvrtan level wheeling with this thing.

 

makes sense, that looks like a beautiful spot, I think you saw my clips in other thread, with 5.29s I just let it walk, the tuning was done by Mr. Sniv above, and I never had to explore wide open throttle in 4lo.

Good luck man.

 

@Vizsla mentioned in another thread that he removed the throttle nannies from 4lo. How did you do that? Was it through a tune or some other means? Completely removed, or just increased the throttle settings and offset some of the nanny?

 

And you have an LSD in the rear, no locker?

 

Yes, just LSD, no lockers.