To my 99 TL owners, what's the major difference between D3 & D4? It seems like when I use D3, I accelerate quicker but I hear the engine revving up more, when I use D4 the acceleration is somewhat slower but I feel a smoother pickup w/o the engine revving so loudly. What's the difference & which one should be used in what driving situations?

 

The D3 will disable the OD, which is the 4th gear.

It is mainly used when you drive in the city, you don't jump back between 3rd and 4th. But I personally think that there ain't too much of a point to use the D3 unless

1. you are under heavy load, so that your engine will be more responsive and allow you to use more engine brake.

2. when you go on a ramp, but don't wanna use the SS.

 

I use D4 and SS only.

 

I use D4 in city and D5 on Hwy. SS when passing another car...

 

D4 for regular driving and SS for racing. You can hold out your gears longer using SS.

 

Strictly speaking, D3 allows your auto tranny to select from any of the 3 forward gears. D4 allows your tranny to use any of the 4 forward gears. D3 also increases the amount of engine braking that you would experience, helping your car slow down when going down a steep hill for example.

In practical usage, you can leave it in D4 all the time and forget about it. You can use D3 to make driving a little more fun, but under those circumstances, the SS is an option too.

-Beb

 

basically -- if you are just driving around normally -- use
D4 (or D5 if newer)... its the best to do for wear and tear, mpg, etc....