Auto Transmission 7AT Rattle at low Rpm's
 

A week ago, my car started having this weird sound coming from the bottom, it would make this rattling noise at around 1.2-1.5k RPM (every time i would stop and go, and when the trans shifts) from 1.5k rpm's up it would go away, at the beginning, thought my FI exhaust may had become loose from one of the hangers, so today I took it to the exhaust shop and noticed everything was ok with the exhaust, checked all bolts, all hangers, everything.

As we studied the sound, found out it was coming from inside the transmission, right where it meets with the engine, its a rattle between 1.2-1.5k RPM's, after that it would go away, you can replicate it by bumping the revs in the low range and also if you hit the brakes and gas at the same time you can replicate the sound continuously. Seems exactly like what the MT guys refer to as clutch chatter.

Transmission shifts perfectly find, everything works as it's supposed to, manual and auto mode, except for the rattling which is very annoying while cruising because the engine speed is around 1.3-1.5RPM's, every time you'd stop and go and when it shifts in the low rpm's. Have any ideas??

Flex plate?

I would get it looked at before in some cases the flex-plate is at fault like member depointfive0/Andrew has pointed out.

flex plate is cracked.

My car is out of warranty, so I want to go ahead an order the part before taking off the transmission, i was looking on courtesypartsnissan, but still not sure.

Which if these two is the one I need?

#1 -PLATE ASSY-DRIVE & GEAR (PLATE ASSY-DRIVE & GEAR - 370Z (Z34) 2009+ :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com)
#2 -PLATE-CRANKSHAFT TO CONVERTER (PLATE-CRANKSHAFT TO CONVERTER - 370Z (Z34) 2009+ 3 7L V6 7-Spd A/T |WITH :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com)

http://i45.tinypic.com/2dguh6a.png

you will also need the 7AT sleeve 12330 if its needed

I know the 6MT guys has to change their bushing but im not sure with the metal sleeve for the 7AT


You shouldnt need #2 but only #1 from that picture you put on.

all you need is the flex plate,, 5 year powertrain warenty ?

Thanks for the help guys!! Just ordered the Flex Plate Part #1

:vuvuzela:
Heyo! Got the answer right on the first guess!

Why can't my flex plate break?!?!?! I want the dealershít to replace parts for free!!!


OP, when you get it out, can you snap some pics?

Here are the pics of the broken plate, my mechanic was even surprised I could've gotten there driving

http://i50.tinypic.com/2ept3iw.jpg

http://i47.tinypic.com/8vna02.jpg

holy %#@ !!!!!
and I thought my first flex-wheel was bad !

Its gonna be expensive for the 7AT owner once the car is out of warranty !
they seem to break way way too easily.

Who did the work?

sometimes I could hear rattling noise at 1st gear (low rpm)... could it be the same (flex plate) issue? I have an MT

You don't have a flex plate

A flex plate is the AT's "flywheel"

Thanks! :tiphat: