bl1nk

No, this isnt the typical question we get about gears "Which ones should I get... I have a -blank-" .. little more technical but possibly easy to answer.

Ok so I know gears allow you to accelerate faster by turning the wheels more revolutions per turn of the driveshaft.. but my question is.. wouldnt this also cause you to slow down faster when decelerating? For example... if youre crusing in 3rd and you let off youll start to slow down, but if you drop it into 2nd youll slow down even faster. So if I go from 3.31s to 3.90s, I know Ill get a big difference in acceleration but what about decerlation? Also could this be harmful to the engine or drivetrain? I know alot of people that drive manuals engine brake alot but Ive never heard of whether its bad for an auto or not.. I like to manually shift my auto and sometimes I use it to slow down, is that bad for it? Thanks.

MBDiagMan

Yes indeed, lower gears (higher numerically) will result in more engine braking. Engine braking is a BAD practice for street driving. I can GUARANTEE you that you can slow your car down cheaper with brakes than you can with the engine, ESPECIALLY if this engine braking is taking place at higher RPM.

Engine braking is a necessary metod of slowing the car on a race track in order to be competitive. It is EXPENSIVE behavior on the street.

BTW, it's not the healthiest thing in the world for an automatic transmission either. It is just that much more heat buildup that the transmission must deal with. If you drive this way consistently with an automatic transmission, that is, engine braking by locking into a lower gear, you need to be changing your transmission fluid OFTEN, and I mean REALLY OFTEN.

Good luck,

CrazyAl

+1

Damn good post!

Archion

+1 I agree with most of that for the average driver, but in my case, if you travel through in the mountains alot, you have to use engine braking unless you want to risk losing your brakes and using one of those lovely p-gravel runoffs to stop... Even disc brakes have their limitations. Now when I am using engine braking I am not rowing the gears, I just pop her out of o/d and do minor braking, the engine does the rest.

Ford_Dude

ok actually the 4.1 means the driveshaft turns 4.1 times to make the wheels turn once (you can verify this by jacking it up and put it in neutral then turn the drivers side wheel 1 revolution)

the gain is from more torque from the simple machine idea of the longer side of the lever is easier to push down but goes a longer distance and applied more force to the other side

bl1nk

O ok, thanks, my mistake.

Thanks for the info guys, and yeah I use it to slow down but its not like.. excessive to where it over revs and stuff.. Ill definately not do it much/if at all anymore. Thanks!

06GT4RAD

One thing i was pleased with as far as the Auto tranny in the Mustang is how it does seem to drop down into a lower gear when you let off the gas ie engine braking. Most cars do not do this and I personally like it. So yes by going the the 3.73 the car will be engine braking but it will do it the way it already does. As for dropping the auto trans down into a lower gear manually it is not going to harm the car and it even says in the owners manual that this type of thing may be needed in certain driving conditions. Go to page 151-155 and read it lots of good info.

Richard

MarioP3_XR4Ti

Of course, if you also drive a diesel truck to tow your toys to and fro, having an exhaust brake to use the engine to slow the rig down is really a good idea. And it seems that most automatic transmissions that are in OD simply freewheel (or feel close to it) when using engine braking. And in lower gears if you want engine braking you need a way to lock the torque converter if you want efficient braking, which really is only programmed into diesel trucks with automatics and exhaust brakes. Of course, with a manual transmission then there is no issue (gas or diesel). I don't understand why you feel it is bad for the engine to use it to compression brake, I'm not saying you're wrong mind you, but I don't understand why. On any car I drive I use compression braking to slow down most all times, though I don't ever over speed the engine. Of course my driving might be more conservative than some.