Mystery knocking sound... - Ford Powerstroke Diesel Forum
Powerstroke.org is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 11-17-2010, 08:01 PM
Compression Ignition Addict
 

Join Date: Jan 2010
Posts: 189
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Mystery knocking sound...

Ok guys, I have a real head scratcher here!

Symptoms:
  • Loud knocking noise coming from engine compartment ONLY when accelerating
  • No knocking sound when revving the engine in neutral
  • No knocking sound when traveling at any speed while in neutral or clutch engaged

So basically, the only time it'll knock is when I'm accelerating in gear, whether it's a 5mph, or 30mph. But as soon as I let off the accelerator it goes quiet.

Possible cause:
  • Bent / bad pushrod - but it rev's and idles just fine at all times as long as I'm not moving
  • Bad injector - possible, but doesn't really seem to fit
  • Bad U-joint - My steering was acting VERY weird earlier in the evening prior to the knocking - but still doesn't make sense that I can go down the road at 30mph and it'll ONLY knock if I'm accelerating. Lay off the gas and the knocking stops.
  • Tranny - shifts smooth as ever with no noticeable decline in performance

Any ideas? These symptoms just don't make any sense to me, but something is definitely very wrong under the hood!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 11-17-2010, 09:57 PM
Rangers Lead The Way!
 

Join Date: Nov 2009
Posts: 11,484
Thanks: 0
Thanked 11 Times in 9 Posts
Feedback Score: 2 reviews
just cause your trans is shifting ok doesnt mean your TC isnt on its way out
Reply With Quote Quick reply to this message
  #3  
Old 11-18-2010, 12:08 PM
Electrical Ogre
 

Join Date: Aug 2007
Location: Calgary, Alberta
Posts: 11,491
Thanks: 29
Thanked 47 Times in 44 Posts
Feedback Score: 1 reviews
Stick or auto? You mention clutch, Joe say torque converter.
What is the frequency of the knock? Does it match the RPMs?
Does it sound mechanical like a rod bearing knock, or something in the body like the downpipe hitting the firewall or engine rocking on loose/broken mounts and bumping things?
Reply With Quote Quick reply to this message
  #4  
Old 11-18-2010, 12:10 PM
Rangers Lead The Way!
 

Join Date: Nov 2009
Posts: 11,484
Thanks: 0
Thanked 11 Times in 9 Posts
Feedback Score: 2 reviews
didnt even catch he said clutch, good eye.
Reply With Quote Quick reply to this message
  #5  
Old 11-20-2010, 06:56 PM
Compression Ignition Addict
 

Join Date: Jan 2010
Posts: 189
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Well I figured it out, had someone listen to it from the outside and he thought it was coming from the rear end. Popped the cover off the rear differential and all the grease pour out filled with a bunch of busted teeth off the ring and pinion. Fun times. Trailered it off to the shop yesterday as this is beyond my capabilities.
Reply With Quote Quick reply to this message
  #6  
Old 11-20-2010, 07:48 PM
Rangers Lead The Way!
 

Join Date: Nov 2009
Posts: 11,484
Thanks: 0
Thanked 11 Times in 9 Posts
Feedback Score: 2 reviews
Ah well that isnt cool. Sorry to hear about that. Coulda been worse
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Powerstroke Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
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
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 10:25 PM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.1
Garage Plus, Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

vB.Sponsors