Knock/rattle from flywheel area

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

jux

Full Access Member
Joined
Sep 14, 2013
Posts
136
Reaction score
0
Location
PA
First Name
Z
Truck Year
86
Truck Model
c10
Engine Size
350
I'm getting a rhythmic knocking sound that seems to be coming from the flywheel area of my '86 c10 350 3 on the tree. I don't know how long it has been going on, I don't hear it over my exhaust unless I'm under the truck.

When I assembled everything around april/june, I used locktight and torqued everything to specs. I don't have time today to check the flywheel for cracks, but other than that, what else could it be?

Does anyone else have or had a tap or knock coming from that area?

Thanks
 

MrMarty51

Full Access Member
Joined
Oct 25, 2012
Posts
7,525
Reaction score
9,383
Location
Eastern Montana
First Name
Martin
Truck Year
1978
Truck Model
K20
Engine Size
400
Cracked flex plate or the T-convertor nuts is coming loose.
If starter is doing weird things, it could be the starter drive is`nt retracting.
 

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
133
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
Three on the tree is a manual trans. But yeah, cracked flexplate or Tq coverter bolts. If you do have the 3 speed Saginaw trans, Have someone press the clutch slightly to see if the noise dissapears. if it does, your throwout bearing may be toast. And at that point, just do a clutch job.
 
Last edited:

jux

Full Access Member
Joined
Sep 14, 2013
Posts
136
Reaction score
0
Location
PA
First Name
Z
Truck Year
86
Truck Model
c10
Engine Size
350
Maybe I'm going crazy, but when I was trying to do what Jim suggested, I could no longer hear the noise at all.

I was hearing it this morning after I changed my oil and happened to go back under the truck while it was running. Then I tried to listen to the sound tonight, but when I got under the truck I couldn't hear it again.
 

zieg85

Full Access Member
Joined
Oct 28, 2012
Posts
175
Reaction score
9
Location
Brighton, IL
First Name
Carl
Truck Year
1985
Truck Model
C20
Engine Size
7.4L
Sounds to me a throw out bearing starting to go
 

jux

Full Access Member
Joined
Sep 14, 2013
Posts
136
Reaction score
0
Location
PA
First Name
Z
Truck Year
86
Truck Model
c10
Engine Size
350
I'll keep listening. Possibly related, but when taking off in 1st, I have been getting clutch chatter that shakes the truck.
 

Jims86

Full Access Member
Joined
Aug 3, 2010
Posts
5,492
Reaction score
133
Location
Patterson,Ca
First Name
Jim
Truck Year
1986
Truck Model
K10 Suburban Silverado
Engine Size
5.7 TBI
I'll keep listening. Possibly related, but when taking off in 1st, I have been getting clutch chatter that shakes the truck.

Tell the clutch to shut the **** up, and get back to work.
 

austinado16

Full Access Member
Joined
May 25, 2012
Posts
611
Reaction score
221
Location
Central Coast, CA
First Name
Todd
Truck Year
1990 w/307k miles on the clock
Truck Model
GMC V1500 Suburban SLE
Engine Size
5.7L TBI/4L60/3.42's
Have a friend step on the clutch pedal with the engine running, while you watch to see if the crank pulley is being shoved forward. If you see the pulley move outward, and then back inward when the clutch is released, you know you've got way too much crankshaft end play, and the crank is knocking back and forth.
 

jux

Full Access Member
Joined
Sep 14, 2013
Posts
136
Reaction score
0
Location
PA
First Name
Z
Truck Year
86
Truck Model
c10
Engine Size
350
Tell the clutch to shut the **** up, and get back to work.

It did just that, thanks for the tip.

Seriously, the chatter went away, hopefully for good. Will post if it re-occurs.

Austinado: I will try this when I get a chance, thanks.
 

Forum statistics

Threads
42,338
Posts
913,930
Members
33,840
Latest member
joseph916
Top