transmission not engaging after coasting backward

Friday is that you?

 

Isn't breakaway stall going to vary with the degree of incline from that of a true full stall?

 

Thanks all - definitely a lot of good info. I replicated the scenario with 2 different make vehicles (Acura & Chevy 1/2 ton) and after a little roll back both transmissions engage and move the car forward without issue. I know it is not good for the trans and I am not intentionally rolling backwards in drive (unless I am testing it), but since I discovered it I want to know why it is happening. I rather catch the problem and have it fixed before it is a big issue. It can't be normal. I always come to a complete stop before shifting, use the brake until it engages, etc... All good suggestions, but that treats the symptom, not the cause. I will try S mode and with the traction control disengaged. When it goes in for the first service I will have Toyota look at it and post their findings. Thanks again everyone.

 

I've had it happen several times on my 2020 Pro, as well. Sitting at a stop light on a steep upgrade. Light changes, I take my foot off the brake and, instead of holding, the truck rolls backward a few feet and makes a clicking sound until I engage the gas pedal. Sure, I could put one foot on the brake and another on the gas and transition from one to another....but the hill holder function is supposed to work.

 

How does it roll backwards in D that makes no sense ... only on a manual does it roll backwards slightly.

 

Exactly....it's not supposed to but it sometimes does and that's why the OP posed the question. It's happened to me twice, always on a substantial grade.

 

Completely normal. Argue all you like about it.

The truck will roll back in 4lo as well and depending on the momentum the truck will actually shut off when gas is applied due to stalling.

Just because another manufacturer behaved differently doesn’t mean there is something wrong with Toyota.

There are dozens of threads on this already....

 

No argument..just stating fact. I've had it happen with other vehicles I've owned but never with the noise and clicking that occurs with the Toyota. May be normal but I never experienced it in my 2004 Tacoma.

 

my truck does this as well/ all the clicking you hear is the traction control/ABS system. If I give it a little more gas it will engage and go. FYI my full size chevy did this on my driveway as well, but without all the traction control racket.

 

Stall stage is the point where your wheels begin to turn . Stall stage is designed into the converter by Toyota . I beleive a factory 3rd gen converter has a stall stage of 1750 rpm . They bend the fins on the impeller , stator and turbine according to the engine torque curve
On a hill ,the converter will continue to stall at 1750 but it takes more acceleration for the stator inside the torque converter to begin driving the input shaft and overcome the weight of the vehicle .

Rolling backwards while in drive doesnt do any damage to the transmission . The input shaft doesnt turn while you are rolling backwards and the forward clutch coasts until the converter begins driving the input shaft .
As long as you are topped up on transmission fluid and the engine is running , your transmission pump is lubing and cooling the transmission .
At idle , You could let the truck roll backwards in drive all day and you will not do damage .
At full throttle , its a much different story

 

I had a similar incident in my F150. My driveway is steep. I had stopped to get mail and noted a letter I wanted to open right away. I stopped on my driveway to open and read the letter with truck in D. I was a bit distracted and not having enough pressure on brake pedal the truck rolled back 3-4' very slowly. My engine died. I had to put it back in Park to restart it. It didn't seem to do any damage, I've had no other issues.

This is something I have to be a little careful about on steep hills with the Ford. My Tacoma seems to hold the truck in place with much less effort in similar situations.

 

The verdict is in. It is "normal." It is the hill holder/traction control. I'm not saying it is right, but I concede it isn't wrong. BTW there are a ton of posts under hill holder function here on TW - Thanks everyone.