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Torque Converter Bolts

Daniel3485

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I've got a 97 C3500HD with a 6.5 Turbo Diesel bolted to a 4L80E (HD) I'm told because of the brake on it.
Could anyone tell me why my torque converter bolts are rubbing my dust cover? I've been told that these engines are supposed to have a shim or spacer between the crankshaft and the flexplate. If this is true, could anyone tell me what size spacer or shim(s) that is required?
Thanks for taking the time to read this and I greatly appreciate any incite.
 

Will L.

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No spacer. You’ve been misinformed.

Wrong bolts, maybe someone through washers in there for some silly reason maybe.
Can you post a picture? Thats the best way for us tl see what you have that’s wrong.

A common error when apart is they put the flexplate on backwards, but that is usually a hell of a racket mistaken for rod knock.
Possibly the cover is installed wrong.

If you fill out your signature line with the truck details, we can see exactly what we’re dealing withand ya don’t have to type it out each time. Mine is a poor example, look on your other thread at how the other folks do it.
 

Daniel3485

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Thank you for your immediate response.
No sir, I don't have any pictures yet but as soon as I'm able to shut the rig down long enough to get those pictures, I will. But to give you an idea whats going on, I bought the truck last year around August and it's ran fine the whole time. I go to drive it to Oklahoma out of the flat lands of Northeast Arkansas this August and as I am ascending up a long hill, the truck downshift and as soon as the turbo spools up while on this hill, it starts this God awful noise like when kids used to stick stuff in bicycle tires and go fast. It has a distinct sound and it sounds nothing like a rod knocking. I only know this because as soon as I could pull off the road and be on level ground, I jacked it up, got under it, pulled the crossover and dust cover off. I saw signs of the dust cover having like a halfmoon rubbed into the front of the inside of it. The bolts showed to have a little rub, but not a lot.
It doesn't do it consistently, just when it's first starting or taking off. As it hits 1500 RPM it gets quiet.
 

Husker6.5

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You two took the words right out of my mouth, guys. Under load the crank is "walking" and that indicates the thrust surface on #3 Main bearing is going or gone. For the converter bolt heads to be contacting the access cover, from looking at my 4L80E I have sitting here, either the cover has a pretty good wanking dent in it or you don't have a thrust surface left on #3 Main. I slapped the cover up in place and looked through the starter hole with an inspection mirror and a flashlight and it eyeballs at about ¼" clearance between the converter/faceplate bolt heads and the cover after I threaded a couple of converter bolts into the bottom two lugs and leaving them protruding about the thickness of the flexplate by eyeball.

The next question that raises is what has that walking done to the rod big end faces/crank rod throws for wear and clearances?
 
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Husker6.5

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Holy shit! That's something I've NEVER seen in 45+ years of wrenching on vehicles! Aftermarket flex plate or OEM, either way totally unacceptable! Honestly, the only "right" way to fix that is to replace it with a NEW flex plate, do NOT try to weld that, either! Even if you drop the tranny and remove the flex plate to weld it, DON'T! Attempting to reweld it can cause further (invisible heat stress) damage to the flex plate and/or throw the balance off. Just be safe and buy a new one! Also, when that one is out, inspect that closely and see if it is indeed a lack of penetration, or as it appears from photo, something broke the weld, such as flex plate flexing (which it shouldn't do!) and if it appears the weld broke, determine the cause of the flex (such as the crank "walking") since now is the perfect time with the transmission out to take off the serpentine belt and check the crank end play with a dial micrometer!
 

Daniel3485

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I wasn't even thinking of repairing it. I'm gonna say it's aftermarket. It's a 97 model and it looks as if it's been replaced before. There has to be something causing trouble somewhere, I found 1 sheared bellhousing bolt and 2 had walked out somewhere down the road.
 

WarWagon

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Make sure you get the diesel flexplate as the tooth count is different for gas engines. We have had a few on here kick the starters off the engine over this wrong part problem.

Common for a broken flexplate. Without a better picture of the entire thing, IMO, we will be seing the plate cracked and broken beyond the welds. Maybe your failed in a weird way as they generally just knock. I also suggest inspecting the torque converter or replacing it with a known good rebuilt one. Converters can "baloon" under engine braking and this is why there is a flex plate, but, yours may be swelled up for some reason. With the broken bellhousing bolts there may be a vibration from a bad TC. Don't forget the crankshaft converter clearance (clutch pilot bearing area) the torque converter moves in and out of. Rust etc. can bind that up. A completely broken flexplate can let the TC move forward.

IMO the converter clutch is the weak link on the 4L80E so if you can get a better converter like a triple disc clutch. It will give you longer service life. The OEM clutch in the converter has a hard time with diesel TQ esp. at the WOT trailer pulling setting in the grades.
 

Will L.

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@WarWagon, I keep forgetting your reputation for beating the crap out of things well beyond their design limitations.
It isn’t that he had to mistreat stuff. Just putting that many miles on it does it. In the fleet we had so many pickups break 100,000 miles per year! Talk about stuff wearing out fast...
 

WarWagon

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I can always serve as a bad example. But, yeah, 550 miles a day 5x a week towing a trailer full of heavy tires and parts on some of the longest and steepest grades in The USA let alone AZ... Turbo boost creep of 2PSI while gaining altitude putting the GM3 past the redline choke point I will always remember.

But with all the blood, sweat, and tears... Just couldn't get enough good parts in one place to keep it going. Many people wanted to see it back on the road. I still can't even turn a wrench at the moment doesn't help.
 

MrMarty51

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I can always serve as a bad example. But, yeah, 550 miles a day 5x a week towing a trailer full of heavy tires and parts on some of the longest and steepest grades in The USA let alone AZ... Turbo boost creep of 2PSI while gaining altitude putting the GM3 past the redline choke point I will always remember.

But with all the blood, sweat, and tears... Just couldn't get enough good parts in one place to keep it going. Many people wanted to see it back on the road. I still can't even turn a wrench at the moment doesn't help.
Yeah, that was about the time I believe, that I came into the forum. I remember reading all the way through Your threads, and when it came time to retire and part out what You had worked so hard to keep going, I too was one that was hoping for a resurrection.
I know about that burn out feeling. Wrenching for the DOT, then, havinf a garage/shop situation and two sets of tools kept Me working after hours, usually beyond midnight, then getting up early and repeating the process, day after day, year after year until i could not do it anymore.
Even today, after being retired for about 12 years, it is still difficult to pick up a wrench to work on a vehicle, although, it is getting better and, I am learning to slow down just a little, taking My time instead of thinking hurry hurry hurry. LOL
 

Husker6.5

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Same here when I had my construction business. A decade spent upgrading/remodeling everybody else's houses (I was a working owner, swung a hammer with my crew and had two lead men each with their own crew, before one staph infection in my leg ended it all) and I just don't have "it" in me anymore to do all the things I planned to do 15 years ago to my own house. I wish I had @n8in8or's energy!
 

FellowTraveler

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Same here when I had my construction business. A decade spent upgrading/remodeling everybody else's houses (I was a working owner, swung a hammer with my crew and had two lead men each with their own crew, before one staph infection in my leg ended it all) and I just don't have "it" in me anymore to do all the things I planned to do 15 years ago to my own house. I wish I had @n8in8or's energy!
YEP, we were men who could do anything, but as time passes we get injured become ill at times and that more than anything has slowed us down to a crawl...so now we walk down the mountain instead of running to do just one thing and that walk lets us have the energy to DO many things.;)
 
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