Knocking In the Motor

B

B-NUTS

Member
Location
Pasadena, TX
When my FX is in drive or reverse, the motor has a small knocking noise. I started noticing it about 3 months after I got the car. Anyone have any ideas what it might be?
 
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:err::tears::ehh:
 
Can you describe the noise a little further? Is it a hardcore knock or is it more of a constant tick? There's drastic difference between valve knock and engine knock, and simple description of the sound can differentiate between the two. Also, it's definitely coming from the front end under the hood somewhere? Not underneath the cabin or under the steering-wheel area?

There's quite a few things it can be... I had a baaaad problem with my front left axle, the bolts sheered right off and it swung around. It happened in drive and reverse, but it wasn't a *knock* it was a *THHUUUD, THUUD, THUD THUD*

Needless to say the FX didn't go more than 15 feet after that without a new axle.

Oh and like they said, Infiniti :embarrassed:
 
well frank mine is when ever you change gears for instant P to R i will here a KNOCK like a hammer hittin metal and then R to N would do the same N to D would do it also

does any of you guys do taht?
 
mine is whenever I change from P to R, P to D or R to D and my car starts moving for 3 seconds or so, I can hear the 'knock' sound. My mechanic said the sound is from the rear axles which is common to FX and 350z when the axles became old.....
 
Mine also makes a knock when changing gears(not always), has been doing it for years.
 
i am sorry i had to bring this thread out of the dead but my car is also making this loud loud sound now a days and then the VDC and SLIP lights come on almost instantly.
what surprises me is that it makes the "THUD" sound only from P to R and only when the car is parked on an incline. the lights go off once i restart the car in neutral.
it doesn't matter where it's facing on the incline or if its a cold start or a warm start, every time i shift to reverse gear, THUD and the lights.
the noise comes from right under my seat.
i have checked the tranny fluid a gazillion times and the level is good on the charging stick.
it's loud, that's what worries me, Is it really not a serious problem?
 
hmm, could there be a leak in your differential box and running dry??

---------- Post added at 02:48 PM ---------- Previous post was at 02:48 PM ----------

try cracking open the rear diff and see if any fluid comes out.....if not then UH OH
 
puhahacj said:
hmm, could there be a leak in your differential box and running dry??

---------- Post added at 02:48 PM ---------- Previous post was at 02:48 PM ----------

try cracking open the rear diff and see if any fluid comes out.....if not then UH OH
Click to expand...

i changed my diff. fluid 3 weeks ago, this problem has been there long before that.
on an incline with brakes pressed, shifting is very tight and when i do get it to move it sounds like you dropped a brick on the wooden floor.
 
I think you're going to have to bite the bullet and take it in to the stealer, especially if it's getting noticeably worse over such a short period of time. If nothing else, pay them to diagnose it for you and then decide how to proceed.
 
bleedingsujit said:
i am sorry i had to bring this thread out of the dead but my car is also making this loud loud sound now a days and then the VDC and SLIP lights come on almost instantly.
what surprises me is that it makes the "THUD" sound only from P to R and only when the car is parked on an incline. the lights go off once i restart the car in neutral.
it doesn't matter where it's facing on the incline or if its a cold start or a warm start, every time i shift to reverse gear, THUD and the lights.
the noise comes from right under my seat.
i have checked the tranny fluid a gazillion times and the level is good on the charging stick.
it's loud, that's what worries me, Is it really not a serious problem?
Click to expand...

I used to have that loud knock when I shift from P to R on an incline. I was told by my friend that whenever you park your car on a incline or decline, first engage your E-brake hard and shift to N make sure your car at not moving at all after you release your brake paddle. Then shift it to P. It will be better for the tranny in the long run. That applies to most of the manual car as well. I have been doing that and found no more loud knock when I shift from P to R or P to D on either incline or decline. I am sure that will give the tranny less stress in the long run as well.

But I would definitely suggest you go get a ODBII scan to find out the error code of that VDC and Slip lights. That does not sound right.
 
White_Hair said:
I used to have that loud knock when I shift from P to R on an incline. I was told by my friend that whenever you park your car on a incline or decline, first engage your E-brake hard and shift to N make sure your car at not moving at all after you release your brake paddle. Then shift it to P. It will be better for the tranny in the long run. That applies to most of the manual car as well. I have been doing that and found no more loud knock when I shift from P to R or P to D on either incline or decline. I am sure that will give the tranny less stress in the long run as well.

But I would definitely suggest you go get a ODBII scan to find out the error code of that VDC and Slip lights. That does not sound right.
Click to expand...

this idea sounds new to me, will definitely give it a try.
i called austin infiniti to ask them about it but he was just stuck on
"we can't confirm anything in particular unless we inspect the vehicle and try to
replicate the problem again" which i understand and i will be visiting them shortly
for the VDC lights.
this is the only problem i have, my car is otherwise perfect.
 
Make you have your brake pressed when shift to N and engage E-brake and slowly release your brake and make sure your car does not move after full brake release. Then you shift it to P. I don't have those "Thud" noise anymore with my tranny when park on incline or decline.
 
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