5AT grind/rattle when accelerating violently
 

Hello,

Been trying to get this sorted out in the maintenance forum, but no luck.

I'm having a problem with the noise in my 5AT 2005.

I hear a very harsh grinding noise at the top (5700-6600 RPM) of 1st 2nd and 3rd gear when accelerating with 100% throttle. As soon as I tip the sport shifter it stops and continues with the next gear until I hit the above engine speed again.

It does not happen:
At the top of 1st, half throttle or when maintaining speed.

It DOES happen:
At the top of 1st at WOT
At the top of 2nd and 3rd, half throttle or WOT

Believe it or not I have never hit the top of 4th WOT :S

I've ruled out the differential, the engine, loose objects, suspension so far.

I just changed the fluid to the recommended nissan atf. However this has been happening before the fluid change, as it was a remedial measure.

If I were to say which location the noise is coming from inside the cabin, it would be right below the rear tower bar in the trunk, but that could be due to the extensive sound deadening along the transmission's centerline. I have also taken out my rear spare tire to make sure it wouldn't be worsened and it made no change. (didn't fit over my brakes anymore anyways, lol).

Any help?

:suicide:

A vid with sound might help

I'll work on that this week.

I'll have to bump this post.

Still having this issue.

Although maybe my hearing has improved/worsened I perceive the noise coming from the engine (which worries me even more)

I tried accelerating the car in manual mode at half throttle all the way through first NO NOISE

SHIFT AT 6800

I tried accelerating the car in manual mode at half throttle all the way through second NO NOISE

SHIFT AT 6800

I tried accelerating the car in manual mode at half throttle all the way through third until I got paranoid looking for cops NO NOISE

So, this only happens under full throttle acceleration.

Sound like a blender turns on from 5000 RPM - Shift.

What could be my issue?

clutch packs are probably going out. since its only under a load. Is the trans stock ? also how many miles are on it? Also have you checked your fluid ? I know that sounds dumb but you never know. Your tq converter might be running dry.

My stock automatic has 98k on it. I checked the fluid level indicator and it is right above full.

How would I make sure this is the problem without dropping it on a long weekend?

Any luck diagnosing this? I have an 05 G35 sedan 6MT with the same issue. It's driving me crazy.