Truck beeps and makes grinding noise when accelerating from stop on a hill

I have a 2017 TRD OR 4x4 automatic transmission, with tow package. Around 90k miles. I bought the truck in 2021 I believe, but I was living in Florida where it is pretty much flat everywhere.

I now live in GA with a bit more hills, and have just noticed, if I am stopped on a hill, when I let off the brake and press the accelerator, if the truck rolls back even just a tad, maybe 6 inches, the dashboard will flash and beep a yellow warning triangle, and then I hear a grinding noise for about half a second before the truck stops rolling backwards and accelerates. If the hill is not too steep, the engine idle will keep the truck from rolling back and this does not happen. It happens on the steeper hills.

This does not seem to be normal and I'm concerned. Could it be a transmission issue? Should I take it to a shop?

 

Normal. Traction control kicking in. Scared the hell out of me the first time it happened too, but I was in the snow and it saved me from going into a ditch.

 

What is the grinding noise though? It's not gonna break anything?

 

it's an anti roll back feature, yeah it's a little noisy as it uses the ABS system too. The Bros and ORs have an electronic brake booster, and while it works well, it does make more noise.

 

Awesome glad I don't have an issue. Sounds like grinding gears when driving a manual.

 

Yeah, it does sound like this and is a bit startling, but normal. You may want to check your tranny fluid level (on flat ground), or do a full change since it's probably due. Probably still won't avoid it on steep hills, but you could also use the parking brake to hold it in place like you would on a manual.

 

I hate that feature- keeps me from rolling back a bit if needing to try again to go up a step or rock - it’s dangerous to have to go into reverse or out of gear to go backwards when you’re on a steep hill because then all you have are your brakes holding you back.

 

Traction Control? Are you sure?
It sounds like the "Hill Assist" is the culprit. Though I'm not clear on if every Taco has hill assist from the factory. (mine does)

 

If you think that noise was fun, try "Crawl Mode". Sounds like someone dumped 10 lbs of random nuts and bolts in the transmission.

 

Yeah, but it works awesomely going up steep hills where you would normally be sliding.

 

Thanks for all the replies guys! I was planning to do a full trans fluid flush and fill after researching for hours and hours on best fluids and best methods to do it. Also want to do the diffs and t-case too.

I haven't used crawl mode yet but I've seen videos of it working and it looks awesome! Nobody has mentioned that it sounds like that though. Guess it's the anti-lock brakes system on that too?

 

Hang on to your socks. It feels as bad as it sounds, and you do not control the gas pedal or brakes ... hang on for herky-jerky.

 

The key to smooth Crawl Control and ATRAC is to keep the RPMs around 2,000-2,500 and let it do its thing. Too much skinny pedal overwhelms the system and it can’t keep up.

 

I don’t have crawl control, but if I understand correctly that is a sort of off-road cruise control, you shouldn’t need to use the gas pedal at all. Just adjust the speed with the dial and let it crawl for you.

I do have ATRAC and know you can use the gas pedal as much as you want and it will be fine. I’m assuming MTS is the same.

OP, I suspect it is hill assist that is kicking in. I don’t have it on my truck (AT only), but I’ve read many posts about it. ATRAC, MTS, and crawl control make a similar sound. I believe it is the hydraulic brake booster that comes with the off-road and pro. I’ve heard the sound a million times and don’t remember ever finding it disturbing, but that could be because I researched the feature before buying the truck.

 

Like you I had no idea what the crap it was the first time I heard it, thought my transmission just broke, LOL!! All to find out is just normal for the hill assist on it.

 

Honestly- I did too! Brand new 2019 with a 1/4 tank of gas on it, and I parked on a steep incline. I called my buddy that was a Toyota tech, and he laughed, gave me a brief description of what was happening.

 

You may want to watch this video pertaining to transmission fluid replacement. AMD (the Car Care Nut) recommends just a drain and fill rather than a total flush. The whole video is pretty good to watch. Also, use Toyota ATF WS.

https://www.youtube.com/watch?v=TevK-u3vkx4&t=1060s