is it normal for the transmission computer to employ engine braking on hills in the LS? I noticed this today after doing about 60 in the back roads of PA going up and down the hills- RPM's shot to about 3k when going down hills and hitting the brakes. Is this normal? I don't recall any of my other cars doing this. Not complaining- just wondering if this is right. Amyone else notice this?

 

Yea I think thats normal, at least my car does that. I like it personally, it keeps you at a generally constant speed down hills.

 

It is normal, only automatically does it when driving down large hills.

If I'm on the Interstate and coming up on a slower moving Semi, I will manually shift down to 4th to slow the car down some so I don't have to use the brakes.

 

Yes it's normal. It has only happened to me while driving down mountains.

 

Yes, not sure how accurate, but I would say the engine slows you down once you go about 10 mph past the point where you let go of your accelerator, atleast that's what I've experienced.

With the active cruise control, it definitely slows you down when approaching another vehicle or going downhill also.

 

Yeah i agree too. This one hill i used on all my previous cars i would have to hit my brakes numerous times going down to stay at like 40mph, with the ls i can cruise down the same curvy hill without hitting the brakes. My wifes c300 seams like it down shift gears when you let off the gas for a period of time.

 

yes it is normal and it is great. saves my brakes in the Texas hill country!

 

Its intended to do this. I give a thumps up to Lexus on that one, saves me from having to ride the brakes.

I also noticed it more when in PWR mode.

 

One time when I was using the adaptive cruise control on the highway, someone decided to pull out in front of me with < 1 car length of space. The cruise control automatically downshifted and used engine braking to create a safe distance and then put itself back into the cruising gear.

I didn't feel the brakes being applied but I read somewhere that the system can use the brakes as well.

I'd rather wear out the easy-to-replace brake pads than wear out my transmission.