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Author Topic: Flexplate possibly cracked?  (Read 4764 times)

Offline blueboy86

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Flexplate possibly cracked?
« on: June 24, 2015, 07:45:25 PM »
1986 305/700r4. Sometimes the truck will crank right up, other times I get really bad grinds. So I don't think this is a shimming problem. My guess is I need to replace the flexplate. Isn't their a dust cover I can remove and check the flexplate? Thanks.
« Last Edit: June 24, 2015, 07:59:27 PM by blueboy86 »
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Offline Irish_Alley

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Re: Flexplate possibly cracked?
« Reply #1 on: June 24, 2015, 09:56:10 PM »
there should be a cover from the factory but who knows if its there. the problem could be a worn spot on the flywheel
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Offline blueboy86

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Re: Flexplate possibly cracked?
« Reply #2 on: June 24, 2015, 10:05:35 PM »
Yeah thats what I'm thinking. So there is a cover? Can you check the starter gap from the cover or just the flexplate teeth?
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Offline Irish_Alley

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Re: Flexplate possibly cracked?
« Reply #3 on: June 24, 2015, 10:10:55 PM »
the cover does also cover up the starter. once you remove it you can pretty much see everything. with the cover in place you cant see the flex plate
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Offline blueboy86

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Re: Flexplate possibly cracked?
« Reply #4 on: June 24, 2015, 10:20:13 PM »
Ok cool thanks.
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Offline Jakethesnake73

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Re: Flexplate possibly cracked?
« Reply #5 on: June 24, 2015, 10:37:03 PM »
I had this issue and replaced my starter and it has only grinded once when i cranked it while the starter was still spinning


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Offline BBM3

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Re: Flexplate possibly cracked?
« Reply #6 on: June 24, 2015, 11:00:52 PM »
After you remove the inspection plate turn the engine over by hand and inspect all the teeth on the flywheel.
If all the teeth are in place and not worn I guess the starter solenoid / Bendix is on it's last leg and not fully extending on every start.
Very common problem with the symptom you described. Cheap and easy to replace.

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Offline scorpion

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Re: Flexplate possibly cracked?
« Reply #7 on: June 24, 2015, 11:01:05 PM »
If you rev it do you hear one or more ticks that sounds kinda like a momentary exhaust or lifter tick comming from the undercarriage?  When I had a cracked flex plate it was cracked around the crank bolts.  Couldn't see it on inspection but it was damaged enough that occasionally the plate would grind when the torque of the starter actually caused it to twist and misalign.  Had the same weirdness you're talking about - many times it started fine it just depended on how the flex plate was lined up when I shoot it down.
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Offline blueboy86

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Re: Flexplate possibly cracked?
« Reply #8 on: June 24, 2015, 11:28:24 PM »
Am I gonna need a special tool to turn the motor over or just an adjustable wrench?  I'm almost certain I'm gonna need a new flex plate though.
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Offline scorpion

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Flexplate possibly cracked?
« Reply #9 on: June 24, 2015, 11:52:50 PM »
Quote from: blueboy86 on June 24, 2015, 11:28:24 PM
Am I gonna need a special tool to turn the motor over or just an adjustable wrench?  I'm almost certain I'm gonna need a new flex plate though.

They make a flexplate tool so you can rotate it while below it. 



If your inspection plate doesn't allow the tool the easiest way is to turn the motor over using a breaker bar on the crank boot inside the crank pully.
« Last Edit: June 24, 2015, 11:54:25 PM by scorpion »
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Offline BBM3

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Re: Flexplate possibly cracked?
« Reply #10 on: June 25, 2015, 05:53:20 PM »
Quote from: blueboy86 on June 24, 2015, 11:28:24 PM
Am I gonna need a special tool to turn the motor over or just an adjustable wrench?

As Scorion said just use a breaker bar or 1/2 ratchet on the crank pulley bolt.
Don't forget to disconnect the battery especially if you remove the starter.

Quote
  I'm almost certain I'm gonna need a new flex plate though.

I'm almost certain you're gonna need a starter solenoid. I hope I'm right for your wallet and time sake.
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Offline blueboy86

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Re: Flexplate possibly cracked?
« Reply #11 on: June 25, 2015, 10:34:06 PM »
Ha-ha right on. Flexplate was in surprising good condition. The bolts for the starter had five washes( shims) removed one from each and started perfectly about 6 times in a row. I feel stupid that it was just a shim but whatever I'm happy. Thanks for the help 
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Offline BBM3

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Re: Flexplate possibly cracked?
« Reply #12 on: June 25, 2015, 11:42:49 PM »
Glad you got it and cheers to you for following up with your solution.
Someday this thread will help someone else.
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