Knocking Noise-Possible Flexplate - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > WJ Grand Cherokee Forum > Knocking Noise-Possible Flexplate

ROCK BOTTOM prices on LIFT KITS at Rockridge4wd!! WANT TO Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineSavvy Billet LED Tail Lights

Reply
Unread 05-01-2014, 11:00 AM   #1
skisprinkle686
Registered User
1999 WJ 
 
Join Date: Dec 2005
Location: Hickory, NC
Posts: 203
Knocking Noise-Possible Flexplate

So I have a horrible knocking noise coming from the driver's side of my 99 4.0. Thought it might the pistons or crank but I called my local mechanic who happens to be a big Jeep guy and he says he will almost bet its the flywheel or flexplate (not sure which is the correct name).

He said if the noise gets quieter as you step on the gas then that is a dead give away. Mine does that exact same thing. I am going to try and upload a video of it tonight or tomorrow to get everyone's feedback. Is this something common and what are your thoughts on that being the problem?

Thanks guys!

__________________
1999 WJ 4.0L V6 Limited
Rusty's 2.0" Lift
Flowmaster 40
Surco Roof Rack
skisprinkle686 is offline   Reply With Quote Quick reply to this message
Unread 05-01-2014, 01:58 PM   #2
harkinsc
Registered User
2004 WJ 
 
Join Date: Apr 2010
Location: Atlanta
Posts: 69
I just replaced my flexplate, torque converter, and bolts on my 4.7L. The rattle / knock was audible from idle to 2500 rpm just as you describe. 3 out of 4 of my flexplate-torque converter bolts had backed out of the torque converter and were rubbing on the back of the block and dust shield. If this is indeed your problem don't just try to tighten the bolts back in as they could be stripped. Just replacing the bolts may not be the best idea either. Carefully inspect the flexplate and torque converter for damage. My issue had gone on long enough to cause some serious wear and deformation on the flexplate and torque converter. See my thread: http://www.jeepforum.com/forum/f310/...knock-2164393/
harkinsc is offline   Reply With Quote Quick reply to this message
Unread 05-01-2014, 02:36 PM   #3
skisprinkle686
Registered User
1999 WJ 
 
Join Date: Dec 2005
Location: Hickory, NC
Posts: 203
I'm for sure going to just replace the flexplate I am just wondering if I should mess with the crank, bearings or pistons while I'm at it? Or if I should just replace that first and see what happens.
__________________
1999 WJ 4.0L V6 Limited
Rusty's 2.0" Lift
Flowmaster 40
Surco Roof Rack
skisprinkle686 is offline   Reply With Quote Quick reply to this message
Unread 05-01-2014, 04:20 PM   #4
Fellows45
Member
1989 YJ Wrangler 
 
Join Date: Mar 2013
Location: Bowling Green, Kentucky
Posts: 222
Quote:
Originally Posted by skisprinkle686
So I have a horrible knocking noise coming from the driver's side of my 99 4.0. Thought it might the pistons or crank but I called my local mechanic who happens to be a big Jeep guy and he says he will almost bet its the flywheel or flexplate (not sure which is the correct name). He said if the noise gets quieter as you step on the gas then that is a dead give away. Mine does that exact same thing. I am going to try and upload a video of it tonight or tomorrow to get everyone's feedback. Is this something common and what are your thoughts on that being the problem? Thanks guys!
I have this same problem I believe! If I give it some gas at idle it seems to go away! Can you upload a video still! This would help me diagnose my problem. How much could something like this run to fix? Is it a DIY? Thanks I'll take all the info I can get!
__________________
2002 Jeep WJ, 4.7, EBC Stage 4 brakes, Bilstein shocks (Still In progress)

1989 Wrangler YJ 2.5, 2 inch body lift, 33 inch tires
Fellows45 is offline   Reply With Quote Quick reply to this message
Unread 05-02-2014, 09:46 AM   #5
skisprinkle686
Registered User
1999 WJ 
 
Join Date: Dec 2005
Location: Hickory, NC
Posts: 203
So I was able to get two videos this morning during warm up. The first video is from the top. The second is from just beside the drivers side shock. I still think it's more than a flexplate. Any ideas?

https://www.youtube.com/watch?v=6SXsEXRP-Ls

https://www.youtube.com/watch?v=RMHEWKxpxZQ
__________________
1999 WJ 4.0L V6 Limited
Rusty's 2.0" Lift
Flowmaster 40
Surco Roof Rack
skisprinkle686 is offline   Reply With Quote Quick reply to this message
Unread 05-02-2014, 12:32 PM   #6
harkinsc
Registered User
2004 WJ 
 
Join Date: Apr 2010
Location: Atlanta
Posts: 69
Quote:
Originally Posted by skisprinkle686 View Post
So I was able to get two videos this morning during warm up. The first video is from the top. The second is from just beside the drivers side shock. I still think it's more than a flexplate. Any ideas?

https://www.youtube.com/watch?v=6SXsEXRP-Ls

https://www.youtube.com/watch?v=RMHEWKxpxZQ
Your videos are listed as 'Private' and we can not watch them.
harkinsc is offline   Reply With Quote Quick reply to this message
Unread 05-02-2014, 12:40 PM   #7
skisprinkle686
Registered User
1999 WJ 
 
Join Date: Dec 2005
Location: Hickory, NC
Posts: 203
Sorry about that. Now you should be able to view them!
__________________
1999 WJ 4.0L V6 Limited
Rusty's 2.0" Lift
Flowmaster 40
Surco Roof Rack
skisprinkle686 is offline   Reply With Quote Quick reply to this message
Unread 05-02-2014, 12:45 PM   #8
harkinsc
Registered User
2004 WJ 
 
Join Date: Apr 2010
Location: Atlanta
Posts: 69
Quote:
Originally Posted by skisprinkle686 View Post
So I was able to get two videos this morning during warm up. The first video is from the top. The second is from just beside the drivers side shock. I still think it's more than a flexplate. Any ideas?

https://www.youtube.com/watch?v=6SXsEXRP-Ls

https://www.youtube.com/watch?v=RMHEWKxpxZQ
It definitely does not sound like a rod or piston. I'd start by having a look at the flexplate. It should be a pretty simple task on the 4.0L.
harkinsc is offline   Reply With Quote Quick reply to this message
Unread 05-02-2014, 02:10 PM   #9
skisprinkle686
Registered User
1999 WJ 
 
Join Date: Dec 2005
Location: Hickory, NC
Posts: 203
Quote:
Originally Posted by harkinsc View Post
It definitely does not sound like a rod or piston. I'd start by having a look at the flexplate. It should be a pretty simple task on the 4.0L.
What signs would you be looking for in a rod or piston?
__________________
1999 WJ 4.0L V6 Limited
Rusty's 2.0" Lift
Flowmaster 40
Surco Roof Rack
skisprinkle686 is offline   Reply With Quote Quick reply to this message
Unread 05-02-2014, 02:53 PM   #10
harkinsc
Registered User
2004 WJ 
 
Join Date: Apr 2010
Location: Atlanta
Posts: 69
Quote:
Originally Posted by skisprinkle686 View Post
What signs would you be looking for in a rod or piston?
For the rod knock, I'd be looking for bearing material and/or metal shavings in the oil. For the piston skirt, I'd be looking for large chunks of piston skirt in the oil. Dip stick is an okay way to check for shavings or bearing material. Dropping the oil pan and visually and physically inspecting the connection rods is your best bet for determining rod knock.

The first thing I would do is take off the torque converter cover plate and bellhousing brace to inspect your flexplate and associated bolts to the torque converter. If that looks okay I would do a compression test on all the cylinders. If that checks out okay I would drop the oil pan and inspect the connecting rods, cylinder walls, and underside of the pistons.
harkinsc is offline   Reply With Quote Quick reply to this message
Unread 06-06-2014, 08:21 AM   #11
skisprinkle686
Registered User
1999 WJ 
 
Join Date: Dec 2005
Location: Hickory, NC
Posts: 203
So now I have a new issue Jeep started making a ticking noise that would get louder as I accelerated. Then yesterday it also started doing it while idling. Was driving it home and heard a loud pop then the engine died. Had to have it towed to my local mechanic who is checking out today.

What do you guys think? Crankshaft? Piston? Timing chain?
__________________
1999 WJ 4.0L V6 Limited
Rusty's 2.0" Lift
Flowmaster 40
Surco Roof Rack
skisprinkle686 is offline   Reply With Quote Quick reply to this message
Unread 06-06-2014, 07:18 PM   #12
KayCeeJeep
Registered User
2004 WJ 
 
Join Date: Apr 2011
Location: Kansas City, Missouri
Posts: 1,145
Quote:
Originally Posted by skisprinkle686 View Post
So now I have a new issue Jeep started making a ticking noise that would get louder as I accelerated. Then yesterday it also started doing it while idling. Was driving it home and heard a loud pop then the engine died. Had to have it towed to my local mechanic who is checking out today.

What do you guys think? Crankshaft? Piston? Timing chain?
Ugh I'd guess piston skirt.
__________________
STOCK WJ WARRIOR
2004 4.0 Laredo Selec-Trac at 123k
General Grabber AT2's
KayCeeJeep is offline   Reply With Quote Quick reply to this message
Unread 06-10-2014, 08:05 AM   #13
skisprinkle686
Registered User
1999 WJ 
 
Join Date: Dec 2005
Location: Hickory, NC
Posts: 203
Turns out there is no compression on cylinders 4-6. Was told the connecting rod on cylinder 5 is broke. Looks like it might be time to cut my losses....
__________________
1999 WJ 4.0L V6 Limited
Rusty's 2.0" Lift
Flowmaster 40
Surco Roof Rack
skisprinkle686 is offline   Reply With Quote Quick reply to this message
Unread 12-14-2014, 11:05 AM   #14
nyks02wj
Registered User
2002 WJ 
 
Join Date: Jul 2014
Location: hopedale, ma
Posts: 23
not to beat up a dead thread, but i have a 4.7 making a noise from the bell housing.. or about 2 weeks now after 2500rpm it goes away.. loudest at 2k.. question is if flexplate bolts backed off can i just retighten them or get new bolts.. also anyone know if i have eto drop the exhaust... i just put the engine into the jeep about 1 month ago.. issue just started arising last week or so.. an help out be greatly appreciated...
nyks02wj is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.