1SlowHoe

iTrader: (28)

Got a video of the sound. Anybody got an idea? The times you hear the knocking go way are when I go to Neutral when moving from R to D. It still knocks in Neutral sometimes and in P but not as loud as when it's in gear.
Ideas so far are:
1. Flex plate cracked
2. Converter bolts backing out and scraping flex plate.
(checked already didn't see any that were backed out)
3. Lifter (Dont think so)
4. Internals of the converter coming undone

Truck still drives fine, just an annoying tapping sound, and it's getting louder everyday

ChevyTruck

iTrader: (39)

I would guess #4. If it was the bolts backing out it would of sheered one off by now, had that happen to me a few months back.

Good luck on trying to figure it out what it could be.

Spoolin

iTrader: (8)

Get a hold or PM turboescalade. He had the problem with the flexplate and he might know if that sound is familiar.

turboescalade

iTrader: (10)

that honestly sounds like what was wrong with mine. All my flexplate bolts backed out and it was really sloppy. The shop told me that I actually broke the flexplate. But if you say that yours still drives then I think your bolts backed out. I wouldnt drive it. Take the bolts out. spray brake clean in the holes and on the bolts to clean them off. hit them with the air compressor and put some blue loctite on the bolts.

1SlowHoe

iTrader: (28)

Think I found the rattling sound. I THINK my flywheel might be slightly damaged...You have any idea how hard it is to get a picture of something like this?

GMCtrk

iTrader: (27)

Welp, glad you found your problem! That's one of the sweet things about the 80e...just get up under there and you have a gaping view of everything. No peeping thru a 1" hole like the 60e.

Is that a 4l60 or 4l80 flexplate?

1SlowHoe

iTrader: (28)

At least 3 fingers are cracked, 2 look like they are almost all the way through.

Oh and the mystery trans plug...it was the fuel composition sensor. lol
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1SlowHoe

iTrader: (28)

Thats what I'm trying to remember...I have an 80E felxplate on the way already. Will either work? The truck came with a 60E but I cant remember if I swapped plates when I did the 80E transplant.

GMCtrk

iTrader: (27)

Just based off your pics i believe its a 60e flexplate based on the dish. 80 plates are flat.

1SlowHoe

iTrader: (28)

I think I did re-use my factory 60E plate. Will an 80E plate work? I already have one on the way. I seem to remember something about spacers and bolt patterns being an issue. I'm not above ordering an after market plate...anything good out there besides the Mezarie or whatever that $400 plate is?