Flywheel area knocking mystery….

[Domterry12]

Ok fellas and felletes, here’s the mystery. I’ll start from the beginning….

I bought this m1009 roughly 2 years ago. I bought it and pretty much immediately lifted it and put 35” tires on it. (I know, blasphemy). Before lifting I had test driven, driven around block a couple times, and everything was fine. Right after lifting, backing out of the garage. I had a knock in reverse. I panicked lol. But soon realized something was knocking the flywheel inspection cover because removed cover and noise was gone. I put it back on spaced with washers And was good. Chalked it up to something with angle of lift or something. Few months later came back, spaced with 3 washers each hole. Went away again. Came back removed cover completely.
Well now it’s back again, even with no cover. I changed the harmonic balancer cuz j had a slight wobble on crank pulley and also seems slight wobble at flywheel/converter.
I was inspecting today and it seems the weight (brake pad looking thing) on flywheel has scrapes and it could be contacting there. I sprayed some paint on it this morning to see if it scrapes off but haven’t had a chance to drive the truck.

Is the weight on the flywheel supposed to face the front side of the truck? I read in another thread it’s supposed to face the rear, that can be my problem if it’s true.

starter looks original and untouched, but I’ve read a lot about it being shimmed and maybe it’s not shunned far enough away?

Im lost, truck runs perfect, has great power, I can’t see it having a broken crank running so smooth. And the knock is not coming from oil pan area i listened with a stethoscope. My ideas are unbolt converter, push it in and run, see if change. Hard to remove starter or fly wheel and then run it LOL,

can the cucv gods please help? @cucvrus @Warthog234 I know you guys know your stuff.

 

[87cr250r]

Take a prybar and bump the converter/flexplate fore and aft. It should move 0.004-0.008".

 

[cucvrus]

The weights on the flex plate face forward. Are you sure that all 6 bolts fastening the flex plate to the torque converter are tight. Are you sure they are M10 if the need to be M10 and or 3/8" if they need to be 3/8" bolts. I have seen them both ways and have determined that the ones I seen with the 3/8" bolts were not OEM transmissions or torque converters. Make sure you check all 6 of them bolts. 3/8" bolts will appear tight in the M10 holes but they are not. I seen the same on several starter bolts. Check back and share your test findings. Thank you and Good Luck.

 

[Domterry12]

The weights on the flex plate face forward. Are you sure that all 6 bolts fastening the flex plate to the torque converter are tight. Are you sure they are M10 if the need to be M10 and or 3/8" if they need to be 3/8" bolts. I have seen them both ways and have determined that the ones I seen with the 3/8" bolts were not OEM transmissions or torque converters. Make sure you check all 6 of them bolts. 3/8" bolts will appear tight in the M10 holes but they are not. I seen the same on several starter bolts. Check back and share your test findings. Thank you and Good Luck.

ok I will pull a bolt and check the thread size in my thread checker. But how do I know which thread my torque converter is supposed to be? I guess i can get my thread checker in there too.but It’s original, everything in this truck is OEM. So you’re saying that oem is supposed to be m10 and aftermarket is 3/8

I kinda have it in my head to just slide trans back and change flex plate cuz every thread I have found on here about noise in this area was cracked flywheel around mounting bolts that u can’t see while it’s in place. My local Autozone has a pioneer FRA-142 in stock. I searched it for an 86 k30, says fits the thm400, 139 teeth, 14.14 Od, and converter hole spread 11.5. Is this the correct flex plate?

 

[gringeltaube]

My local Autozone has a pioneer FRA-142 in stock. I searched it for an 86 k30, says fits the thm400, 139 teeth, 14.14 Od, and converter hole spread 11.5. Is this the correct flex plate?

Yes, that's the correct part.

 

[Domterry12]

Well, I think this could be it…
.

oh and btw didn’t remove starter to get out. Left it in didn’t wanna deal with shimming , and that thing is huge!!!

 

[cucvrus]

Good job

 

[Domterry12]

She’s purring like a kitten!!!

 

[sneekyeye]

LoL, you're lucky you got that flex plate out and didn't ride on it any longer. That thing looks moments away from grenading apart.

 

[nyoffroad]

LoL, you're lucky you got that flex plate out and didn't ride on it any longer. That thing looks moments away from grenading apart.

I wonder what would happen in that case? Things would get chewed up for sure, but do you think the broken pieces could jam up enough to crack the bell housing? Inquiring minds want to know.

 

[cucvrus]

I fixed a few like that. 1 truck needed a new transmission case. Another one has 2 holes thru the upper bell and the owners were willing to take the risk. It all worked out. They ran the trucks several years before upgrading. The plow tuck split the bell housing and lower cover. Happy Holidays.