kylesc400

its kind of weird, when i have my overdrive ON i can let off my gas and let the car's weight take me along just like in any other car. however, when i have overdrive OFF, as soon as i let off my gas, i get a braking effect. is this natural engine braking or is there something going on why my tranny? ive never driven another car that does this.

voeltz

engine braking

SC300Es

and you also get a better throttle response. in later models, where you have separate OD and 3rd gear selection by selecting 3rd gear you get the feeling you described. driving in the 3rd gear also eliminates that annoying lag between 35-50 mph you get with OD.

machinegt

good for holding speed while taking corners and jetting out too.

pop that gear down and watch your rev's spike up near redline and listen to the rush of the v8 pistons buzz generating maximum hp and torque.

overdrive gear is for saving u gas money.

don't be afraid to get some good revolutions in for fun.

kylesc400

yea, i love driving with OD off, but i dont do it much cuz my engine doesnt run as smoothly. i have that infamous "40mph vibration" that i cant seem to fix. ive searched and found several different theories as to what causes it (bent wheels, old tranny fluid, etc) - i had the dealership change my fluid which made no difference at all. im about to put on my gs400 rims as soon as the snow melts. im hoping thats it. anybody else have any ideas?

voeltz

that 40mph demon is a strange one. I've heard it has something to do with the diff. I think it's just the torque converter because it only shakes in a certain gear right? i'm not a mechanic though, so who knows.

V8RWDHP

When OD is off you have a shorter top gear because it won't shift into 4th gear( your OD gear). It stays in 3rd. Just as if you put a car in low 2 it won't shift out of 2nd to 3rd and then if you get goin and then let off the gas it will really pull back because you have an even shorter gear. I leave the OD off untill I"m going to go over 45 mph for a while, that's when it saves your gas

kylesc400

does this engine braking effect add any unneeded/extra wear and tear on the engine compared to when OD is on (beyond the fact that its already running at higher rpm's)?

voeltz

no it doesn't, its actually easier on your brakes. Lexus actually recommends engine braking (at reasonable speeds). I always engine brake going down hill or if i'm coming to a stop light or sign.

voeltz

forgot one thing though, you will obviously loose fuel efficiency when driving at higher RPM's, and driving at excessive high RPM's does promote unneeded engine wear. SO if you're just cruising along, drive w/ OD on. If slowing down for a stop or if slowing your speed down, go ahead and engine brake.

joeyc2

iTrader: (1)

you know, on some days my car seems to run alot better when OD is off, but some days it drives better with it on and on some days it just drives like ****. why is that?

SC300Es

I don't if it is only for transmissions but a lot of times most cars I owned run different on different days. Sometimes they feel smooth sometimes very rough. I think it depends on the temperatures outside. If it is too hot or too cold they don't seem right.