Downshifting Automatic Transmission

hyundai
sonata

#1

I like to use the “manual shifting” option on my 2006 Hyundai Sonata. That means I move the gear shift lever to the right, then pull it backwards in the slot to downshift when approaching a red light or stop sign.

My wife remembers the advice from several years ago that brakes cost less than a transmission.

Who’s right?


#2

Your wife is correct.
While it may be enjoyable to occasionally use the manual shift feature on your transmission, constantly using it to slow down for traffic lights is putting excess wear and tear on your very expensive transmission.

Just out of curiosity, do you have the fluid and filter of that transmission changed (not flushed !) every 3 years/30k miles? If not, you can look forward to transmission failure any time after ~90k miles. Whether Hyundai specifies this service or not, it is necessary to keep the transmission working properly during the car’s lifespan.


#3

Your wife is right! Stop fooling with the transmission downshift in traffic; there are 2 situations where you do this; (1) when going down a steep mountain road to save the brakes from overheating, and (2) going up a steep mountain road to give the engine more power.


#4

As usual, your wife is correct and you are wrong. How do I know this is “as usual?” I know this because this is a boneheaded thing to do and you seem to have a very smart wife. Your car was designed to be put in drive and left there until it is time to put into park or reverse.

Each time you take the car in and out of drive, the drivetrain components, like CV joints and transmission linkage, takes a jolt. Those jolts might not lead to failure today or tomorrow, but they will hasten the demise of your drivetrain components. Even when you are waiting in line at a drive thru, leave it in gear.


#5

Each time you take the car in and out of drive, the drivetrain components, like CV joints and transmission linkage, takes a jolt. Those jolts might not lead to failure today or tomorrow, but they will hasten the demise of your drivetrain components.

I agree that every time you take it in and out of drive, the clutches and bands get worn a little bit. Better to wait with the parking brake firmly set instead of shifting to park.

But how is it bad for the drivetrain components to “take a jolt”? Every time I start from a stop, I’m effectively putting the car from neutral to drive, as I let the clutch out. I’d bet my car does this thousands of times more than an automatic would and it is doing just fine.

As for downshifting an automatic, I guess it is fine as long as the engine computer is programed to rev match. If not, the transmission’s bands and clutches are flinging the engine up to speed when you downshift and they’ll wear out much faster.