Downshifting in an automatic. 4th to 1st

transmissions

#1

So I have an automatic 2007 Honda Accord with ~41,000 miles on it. I live in Lake George, NY, but I’m down in Durham North Carolina for the summer. Last night I was driving one of my friends home. I was driving at around 45 mph and I’m guessing the car was in 4th gear when my friend shifts down to 1st gear. I immediately put on the breaks and after about 2 seconds I shift into drive again. I didn’t hear any pops/bangs and the car appears to drive exactly as it usually does. Should I be worried about my engine?
Thanks,
Chaz


#2

Manual transmissions are pretty tough. I’m sure it’s OK. I would not let your “friend” in the car ever again though!


#3

It was an automatic transmission.


#4

Sorry. It dropped down out of over drive. The torque converter is a viscous coupling and should protect the tranny.


#5

with friends like that…

he would have walked the rest of the way if I was driving.


#6

Most modern transmissions protect themselves from this type of abuse by not doing destructive things to themselves…


#7

At least your “friend” didn’t shift into park.


#8

@sgtrock21‌
Out of curiosity, what would have been the implications of that?

Thank you to everyone else for answering. I’m getting the impression that it wasn’t desirable behavior, but It’s not a BIG issue to vehicular health. Akin to stubbing a toe?

It isn’t really relevant, but for those of you who are curious, she was drunk and upset and wanted me to pull over. She said that she’d find her own way home and I didn’t want to leave her in the middle of nowhere so I kept driving to her house. We were almost there when she decided that she’d downshift.


#9

I understand and I figured she was drunk. Your are a good friend to driver her home. Next time put her in the backseat and buckle her in. That should keep her away from the controls of the car. If she had put it in park it could have killed the tranny and may have caused you to loose control of the car. You both could have been killed by her drunken stupidity.


#10

If she had been able to successfully engage park it would have completely locked the driving wheels which in your case are the front. Your Honda would have went into a skid and being a FWD your steering would have been ineffective. It could have resulted in a very serious crash. If a crash was avoided it could cause transmission and front tire damage. At the very least it would have ruined a pair of underwear!


#11

@sgtrock21‌ On most (if not all) electronically controlled transmissions made in the last 20 years or so. Shifting in Part at high speeds would’ve resulted in nothing happening. Modern automatics have fail safes built in to prevent damage from such incidents. Likes going from drive to 1st, will only result in the transmission downshifting into the lowest gear that won’t result in the engine speed redlining.

The idea of shifting into park at speed and having the wheels lock up went out in the late 80’s and early 90’s when hydraulically controlled automatics were phased out.

No damage was done to the OP’s car.


#12

FoDaddy Thanks. I was thinking that was the case with modern vehicles. That is why I used “If she had been able to…” I’m just not up to speed on these features as my mechanic training ended in the mid 1970’s. As much as I like these idiot resistant features I know that computers can fail. I’m also pretty sure I could mechanically over-rev my 2010 Kia with a 6 speed manual by shifting into 1st gear at highway speed. Not that I ever would.


#13

you did your good deed. in that case, I would not have made her walk. I too have helped drunks get home and suffered for my efforts.


#14

wesw The suffering usually involves dealing with urine and/or vomit.


#15

knfenimore sez “next time put her in the back seat and buckle her in” I say put her in the trunk.


#16

The gear shift is not connected to the transmission. If you pull the center console off, you will see that it is connected to a bunch of switches that go to the PCM. The PCM sends signals to the transmission for the actual shifting. The PCM is smarter than your passenger (at least smarter than the passenger when drunk) and would not allow the transmission to be damaged.


#17

keith So that’s how the magic works.


#18
"The idea of shifting into park at speed and having the wheels lock up went out in the late 80's and early 90's when hydraulically controlled automatics were phased out. "

With some makes, it went out even earlier.
I can recall being a passenger in a friend’s mid-80s Corolla when it stalled out at high speed, as a result of the famed Toyota igniter problem. When he attempted to restart it, instead of shifting to neutral, he threw it into Park–at ~55 mph–while I screamed NO!!!.

However, my panicked reaction turned out to be unnecessary, as you could clearly hear the pawl ratcheting, rather than engaging. When he got the car back after replacement of the igniter, I tested the transmission, and the Park function operated flawlessly, so it was possible to shift a non-electronic trans into Park without causing damage–as long as it was a Toyota.


#19

Your friend did not shift into 1st. Your friend only moved the shift lever into the first gear position. The tranny is actually shifted by a Transmission Control Unit (a computer), and would not allow the tranny itself to shift until it could do so nondestructively.

You’re fine. No damage. Except that your friend will have to walk home from now on… or at least he would if he were MY friend!


#20

“The gear shift is not connected to the transmission.”

Does NOT apply to 2007 Civic or 2010 Insight (don’t have shop manual for Accord).