Is this normal engine braking

This is normal. The hill coming into my neighborhood made my 2008 PreRunner do this exact thing every time I came in. I would be acceperating from 2nd to third while going down a steep hill. As I neared the bottom I would let off the gas and the truck would linger in second gear then ka-thunk into 3rd. I thought it was solely a qwuirk of that truck until I bought a 2005 DCSB with the same gear ratio. It does the same thing.

What you experienced is normally called downshifting, but engine breaking is not wrong either.

. The transmission and ecu are sensing that your vehicle is accelerating while your foot is off the gas, so it tries to break. Normally your transmission downshifts whenever your foot is on the brakes. The slight rise and fall in RPM without a change in speed is the Variable Valve Timing kicking back in and is quite normal for this vehicle. A good method is to put it in 4th while going downhill in the mountains if you are only doing 50mph.

Cheers.

 

That was the point in my first post, engine braking is using the engine to slow the truck.

 

And that is correct.

 

If you monitor your A/F ratio you will see it's injector shut off. The ECU shuts then down for increased fuel mileage.

 

Lol. Tacoma's with jake brakes!!!!

 

Lmao, that's what I was thinking too.

 

This is what I thought it was too. I didn’t notice the truck changing gears. Only seems to happen when I’m coasting down hill in D.

 

It's downshifting from 5th to 4th and if you lean on the brake a bit more it'll go to 3rd. I try to get the truck to do it on downgrades all the time. Sometimes I can stay at the preferred speed without ever having to hit the brake.

 

Next time I should look at the tach and see what’s going on. Seems to happen more often when pulling a trailer or more accurately being pushed by a trailer.

 

Almost all automatic transmission vehicles cut fuel supply when coasting, especially when going downhill. The computer will give it just enough to not completely stall and no more. That is why some vehicles ''drag'' more when coasting. Others tend to freewheel a bit more and provide less engine braking but fuel supply is still curtailed over putting the transmission in neutral and coasting and it is MUCH safer to keep it in gear in case one needs to hit the gas quickly to avoid some road hazard or issue. Some states have made it illegal to place a vehicle in neutral and coast.

 

Like they would ever know...

 

I’m aware the transmission can be placed in neutral, but over time this becomes very repetitious and annoying. Not to mention, it results in needless wear and tear on the relevant components.
Please expand on your disagreement with my post, point by point.
Additionally, explain how everything I said was “pretty much incorrect.”
Do let me know if you have trouble understanding my request for clarity.

Thank you.

 

Why would placing the transmission in neutral cause more wear on components with the engine running lubrication is still happening?

Why isn't it desired when not towing or hauling a load. My first car was a 1949 Ford Coupe manual and it used engine braking when you let off the gas pedal. Every car/truck I have driven since does the same also.

Every pickup truck / car on the market doesn't have an engine braking disable feature. When you let off the gas the engine friction slows the vehicle. Be more specific. Which trucks have this disable feature?

It doesn't introduce more wear and tear on the engine, transmission. They continue to turn and are lubricated as normal.

Modern engines cut fuel to the injectors so there is no impact to MPG.

The failure possibilities are the same on mechanicals and electronics.

I agree it is cheaper to replace brakes than a torque converter or transmission control module.
But engine braking isn't going to cause an increased failure of these components unless there are other problems.

You are welcome.

 

Ok guys help me out here. What is engine breaking?

Isn’t the friction in the transmission not the engine?

 

The Misinformation knows no bounds. If you downshift, and let off the gas the vehicle will slow. The engine will not continue to rev up if you let off the throttle,.so it will naturally slow the vehicle down. This happens in all normal Automatic and Manual transmissions. Motors aren't perpetual machines. They need energy and fuel to rotate. Every single component of a motor-driveline creates more load on the motor such as power steering pump, alternator,.AC compressor, changing from piston movement to crankshaft rotation, changing driveshaft rotation to wheel rotation. When you stop giving the motor fuel, all these components slow the motor down. If you are in gear it will slow the vehicle down without killing the motor. If you never touched the gas again, and never touched the break it would eventually cut off when the rpm reached it's lowest operating speed.


When you are simply decelerating the automatic transmission will simulate heel toe shifting where the break-clutch-throttle are operated at the same time. This makes the transmission run much smoother and prevent wearand tear. Have you ever tried downshifting in a manual and it make a aweful grind as you try to slam it in a lower gear? This happens due to you not syncing the engine rpm with the speed of the input shaft of the transmission. Here is a video showing heel toe shifting which is for downshifting at speed. Race drivers and manual drivers who are skilled at driving use these techniques when racing driving with loads. It makes the vehicle run smoother.

Play close attention to his right foot. It operates the break and gas simultaneously to aid in smooth shifting. This is done to keep the motor in a higher rpm where the power is,.and to help slow the car down.

His throttle technique is pretty rare and not part of this discussion. He uses the throttle and his seat of the pants to feel the grip in the car. Much in the same way traction control.works, he modulates throttle input to find maximum traction in each corner. Again, this is not part of this discussion .

https://m.youtube.com/watch?v=8By2AEsGAhU

 

Have you checked the fluids at all to make sure that the levels and viscosity are OK?

 

I did check them years ago. Level was fine. No burnt smells and no leaks yet.

 

There is friction in both. But the largest part of the braking effect comes from the compression in the cylinders.

Explanation:

https://www.holtsauto.com/redex/news/what-is-engine-braking-and-can-it-harm-your-car/

https://www.yourmechanic.com/article/what-is-engine-braking

 

Thank you!