Sometimes i will gear down to cause less stress on brakes, like 3rd.. then 2nd.. and then sometimes to 1st just before car comes to stop. is this not good for the tranny? or down hills i'll gear down. whats considered a "don't do" for the tranny more less?

 

the brakes are designed to stop or slow down the car.
the 2nd gen TL's tranny is known to be made out of glass....why would you put more strain on it!?

 

I see your point. A good one at that.

 

I only use in to shift up never down.

 

I Always use the trans to Brake when Going down Hills or Highway emergency braking...

But in City? I leave it to the brakes to do the job....

 

you should be ok if you don't downshift to 1. never downshift to 1 even with a manual. when i used to drive manual i used the brakes in the city -> i always held the gear or dropped into neutral depending on situation then at full stop shifted into 1st. i only used engine braking in twisty roads and downhills, usually 3rd gear. however that's not to say its entirely ok to downshift in other gears. if you have already done 2-1 downshifts then you have already shortened your transmission's life significantly, specially for a 2g TL.

i think 1 reason why im still on my original 5at is avoiding 2-1 downshifts as much as possible and shifting early from 1-2 (easy on throttle off the line). another thing, never go WOT while holding top gear, that puts too much strain on transmission as well ie. full throttle at 2500rpm while holding 4th gear.

 

Your tranny already does that automatically. Thus, it is an automatic tranny.

The car will downshift when it needs to. Other than that, don't downshift to save brakes. Brakes are cheaper than tranny.

 

That has nothing to do with it. The problem child in our trans is 3rd. in and out of 3rd is where it adds the most wear to the trans.

 

I ALWAYS use my lower gears to assist in slowing the car down. It's not "bad" forthe transmission per se, but it not good either. Because the motor is not using the friction to reduce vehicle speeds as well as taking on the momentum of the vehicles weight on the opposite sides of every gear within the case, it causes unnecessary wear on parts inside of it. So like I said, it's not bad, it's just another stress factor on the components. I will tell you that a very prestigious transmission builder I work with on occasion did tell me once that because it wears the opposite sides of the all the teeth in the gears, it will mis-shape them and potentially cause damage depending on the amount of wear on both sides of the teeth. I agree with the worse case scenario of his explanation but not for most typical cars and their drivers.

 

Brakes are for stopping. Trans is for going. Simple. Engine braking is for big rigs. We have nowhere near the weight so there's really no need. 4 wheel disc brakes are just fine. I worry more about my tranny dying then my brakes wearing. Set of pads is cheap, replacing the trans, not so much.