92PF4X4

All, I just started noticing the following noise which really worries me. As I coast at some crusing speed, I hear a noise that sounds like someone is letting the air out of a balloon, like something flapping air or some loose object. Given that I noticed this while coming home from a 200 mi trip, I've had plenty of chance to experiment. Here is the behavior:

- If I accelerate significantly (push on gas pedal), the noise goes away.
- If I decelerate (let the foot off the pedal) the noise goes away.
- If I repeat the small acceleration/speed maintenance exercise while going downhill, there is no noise.
- As I Accelerate/decelerate the noise appears briefly as the throttle goes through the position of 'same speed'.
- This happens at crusing speed, when the transmission is in "D"rive. When I'm speeding up from a trafic light, or the tranny is in 1 or 2 gear (even in the D position at low speeds) there is no noise.
- If I stay at cruising speed with the pedal at coasting position (or use the cruise control), the noise is constant AND I hear some kind of sqeal (low pitch, unlike that of sqealing belts, but maybe trannny belts??).
- the noise does not appear to be related to speed (same behavior at 50 MPH or 70 MPH) or RPMs.

I fear this might be something with the transmission, where when there is little tension something is loose and flaps around. If I then apply more torque (or fully release it from torque), the noise goes away. Or maybe something with the differential(s).

Does anyone have any idea?? Tranny, differrential, vacuum system....??? I'm really concerned this could torun into something very expensive if not welldiagnosed promptly!!

The truck has 120k mi, and the tranny was replaced at about 95k. One piece of info that might provide a clue is that I tried to shift off from 4x4 4H mode about 10 days ago as I went through some rough weather (city driving, but flooded street), and the car made a lot of noise. I stopped after about 1/8 mi, read the manual, and learned that a short drive in reverse would unlock the differential, and it did. Could this have caused some damage??

I'll be happy to provide more info and answer specific questions.

Thanks in advance!

bhansen1

I am having the exact same problem with my Nissan Maxima.
What was your conclusion and how did you fix it.
I have a mechanic that wants to retool my fron brake rotors,
but I don't think that is it.

What was the cause of this problem for you?

Thanks!!

Bob HAnsen

Xeno

That message is 21 months old. He only has 10 post in 2 year. So I doubt you will get an answer (from him). You not talking about the one window down and all others up?

X

bhansen1

I did notice that the message wa very old. But I thought I'd give it a shot.
What do you mean by "the one window down and all others up"?

Thanks, Bob

mightymouse

If you have one window rolled all the way down and the others are all up, while cruising at a steady speed, the air turbulance caused by the one window open wil make a "flapping" sound that is loud and annoying as hell. Next time you have that problem, open another window and see if it goes away.

__________________
The only way to achieve the limits of the possible is to go beyond them into the impossible - unknown

Xeno

Bingo...



an easy fixer.

X

1997XETruck

Wow.... that's great internet diagnostics there mightymouse! I would have never gotten that out of the question!

Heath

__________________
1997 Nissan XE Truck - 133,000 Miles
1990 Infiniti Q45 - 91,000 Miles
2005 Infiniti G35 Sedan - 34,000 Miles

bhansen1

Thanks!, but it happens regardless of the windows.
When decelerating (i.e. coasting) above 30 or 40 mph there is
this choppy clunking noise and vibration.
(Very consistent) I don't know what it is yet.
I may head over to a Nissan Dealer.

Thanks, Bob

jerryp58

I wonder if you have a broken motor mount.

__________________

Jerry
2004 Frontier, King Cab, XE, 4x1, 4-cyl, 5-spd

makaveli

that happes to me... does this mean the chasis is out of alignment?

Xeno

No just an air pressure equalization thing.

makaveli

so it could be struts are shot?

bhansen1

Well the strange noise went away on it's own.
a Mechanic tooled the front rotors and replaces the struts and
the sound was still there when over 40 mph and coasting.
The mechanic replaced the original struts.

All of a sudden I didn't notice the noise anymore..
I'm not sure why!!

ANy ideas on what may be happening?

THANKS!!

Bob Hansen

92PF4X4

Bob,

sorry I indeed have not been checking this board for a while.
In my case, I think the problem was that I was running on hte spare tire, which is different from the other tires, causing the differential to work harder.

I replaced the original tired (fixed) and changed the tranny and diff fluids (it was due anyway) and the problem did not show up.

I'm glad my description was at least useful so that you did not have to type i again!!!

92PF