Weird knocking/grinding sound when I first shift into drive?

transmissions

#1

My car is a 2008 Nissan Altima 3.5L. It has an automatic cvt transmission. Here’s the scenario: I turn my car on and shift into drive. I’ll drive for maybe 10 feet and I will hear this strange sound that can only be described as a dull knocking followed by a dull scraping sound. The dull scraping sound will last for about 5 seconds. The sound appears to originate from behind the gas pedal, and I’m think I can feel the gas pedal vibrating very slightly as it is happening.
The only condition that makes this sound happen is when I shift from park or reverse into drive. If I start my car and put it in drive it happens. If I’m at a red light go to park then drive, it happens. If I turn my car on, go in reverse, then drive, it happens. However it doesn’t happen if I just stop and don’t change the gear selector. It’s been happening since I bought the car at 56k miles, I’m at 69k now. I haven’t seen any decrease in performance, the car runs like a champ. I will answer any questions I can, any suggestions?


#2

@Muffins4All
Does This Car Have ABS (Anti-Lock Braking System) ?

ABS systems run a “self check” when the vehicle first starts to move.

Nissan put out a Technical Service Bulletin #NTB10-077 (CLICKING, KNOCKING, CLUNKING, BUZZING noise coming from engine compartment) to address customer complaints of this sound. The bulletin refers owners to their Owners Manual, section 5, Starting And Driving, Brake System, for more information.

There is probably nothing wrong, but rather the car is making sure everything’s OK.

CSA


#3

@Muffins4All
"If I’m at a red light go to park then drive, it happens."

Are you positive about that? Please try it again, but not at a traffic light. I hope you don’t ordinarily put the car in PARK at stop lights. I advise against it.

Anyhow, I found a little newer amended version of the TSB, NTB10-077A that includes newer models that may have 30MPH self check logic, rather to earlier lower speed checking systems . Please read the whole bulletin.
Link: http://www.alldatadiy.com/alldatadiy/DIY~G~C45827~R0~OD1~N/0/138181779/138629620/138629625/138629627/34853741/34850750/42063452/173755221
CSA


#4

Thanks for the response! I got in my car last night and did some more troubleshooting. Here’s an update: my previous statements are a little wrong. The sound only occurs when I go into drive after the car is turned off then on again. So, I get in the car turn in on, go into drive, it happens. The car is on, I turn it off then on again, go into drive and it happens. Going from drive to park to drive doesn’t make it happen like I previously said. And no I don’t make a habit of going into park at a stop sign, that was just for the purposes of this little test. I read the bulletin and it describes exactly what is happening, the car does have abs as well. This is a huge relief. Thanks for your help!


#5

@Muffins4All
"I read the bulletin and it describes exactly what is happening, the car does have abs as well. This is a huge relief. Thanks for your help!"

You’re welcome, glad I could help.

I have 5 cars with ABS (4 GM & 1 Chrysler) and the only one that makes any ABS self check noise (crunching sound) is the Dodge Caravan. The GM cars are silent.

If your Altima ever flunks its test then an ABS light should illuminate on the instrument panel to let you know about it.

Now, about the muffins… I’m into kind of healthful eating… have you got any with whole grains that have little or no saturated fat? Poly or mono fat is OK. :smile:
CSA


#6

Banana Nut Muffins only good sir, free of charge this time around. Have a wonderful day!


#7

Muffins4All
"Banana Nut Muffins only good sir, free of charge this time around.
Have a wonderful day!"

Thanks, they’re delicious! You have a good one as well!
CSA