Need help! Think I've done some kind of damage - VIDEO of noise

[mod66]

OK so tranny is out! Second time round only took 1 hour unlike a month first go.

Anyway below picture is exactly what I found when I lowered away tranny. As you can see one bolt is all the way out. What you cant see is the 5 others were all finger tight. Note the oil striations that you can see starbursting out of the loose bolts from the crankcase.



This is the damage it did to the $1300 torque converter. Luckily its just a rub mark - no doubt this was the noise. 



Front pump and input shaft look like they survived unscathed



Flexplate is a brand new SCAT - check out this bolt hole - no doubt damaged by the vibration. Even though its a small nick I'm going to go with another new flexplate. $100 loss but I'm not dropping this tranny again. You will also note there is no reinforcement plate installed (I bought one today for $20).





Now these bolts were ARP - I measured the under head length (UHL) as .680 inches. The ARP part number is 200-2902 which most websites such as Summit list for both Chev and Ford small block. Now when I measure the actual hole in the crank it is .823" long. You then need to add thickness of flexplate and reinforcement plate which means you need an actual UHL of 1.077" (lets call it 1"). Fortunately ARP make this and it is part 200-2802

So I think the failure was a mix of no threadlocker, inadequate torque and insufficient bolt length.

Incidentally bottom end looks good to me.

[shaunp]

On most cranks the bolts go into the engine  all the way through the crank I glue them in to stop any oil leaking past them.

[shaunp]

Also the slot in 1 bolt hole is normal that's how they are

[lukep6470]

You need to use at least mid strength threadlocker (Blue) and I think it is 80ft/lb.  Which means you will need someone on the front crank bolt to hold the engine still while you torque it up. 

Don't just use a rattle gun which I've seen some workshops do.

[barnett468]

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You should have at least 8 mm from the end of a bolt to the bottom of a blind threaded hole.