Transmission bellhousing mystery hole

Maintenance advice to keep your Spider in shape.
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Spider951
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Your car is a: 1981 Spider 2000
Location: Tuscaloosa, AL

Transmission bellhousing mystery hole

Post by Spider951 »

What is the purpose of the threaded (M8 x 1.25) hole in the bottom of the transmission bell housing (it is threaded completely through the housing)? Thanks

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18Fiatsandcounting
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Your car is a: 1969 and 1971 124 spiders
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Re: Transmission bellhousing mystery hole

Post by 18Fiatsandcounting »

I don't recall seeing that before. My guess is that someone drilled a hole and tapped some threads in it, perhaps to attach a bracket to the outside of the bellhousing. Maybe a bracket to hold the exhaust downpipe from rattling? That's what the bolt you see to the left of your threaded hole is for: an exhaust mounting bracket for certain model years.

-Bryan
Spider951
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Re: Transmission bellhousing mystery hole

Post by Spider951 »

That makes sense. I don't recall seeing anything attached there, but the hole appears to have no purpose for operation of clutch or transmission that I can tell. I only recently noticed that it is threaded. I wondered about a ground strap perhaps, but at the bottom of the bellhousing ???
18Fiatsandcounting
Posts: 3799
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Transmission bellhousing mystery hole

Post by 18Fiatsandcounting »

That new bolt hole is not stock as far as I know. Someone added it.

Actually, now that you mention it, it could be where the ground strap attached from the body to the bellhousing. Normally this ground strap is attached to one of the larger bolts that attach the flywheel inspection plate (cover). There are 4 bolts, two M8x1.25 and two M6x1.0. It's pretty common to strip the threads on these since the bellhousing is aluminum, so maybe a previous owner just drilled a new hole rather than fix the stripped threads?

-Bryan
Spider951
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Re: Transmission bellhousing mystery hole

Post by Spider951 »

Thanks for the reply and info. In answering the original question you also provided an answer to another question I have had, i.e. the purpose of the "bolt to nowhere" - the one to the left of the threaded hole in the photo.
BEEK
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Your car is a: 1975 Spider
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Re: Transmission bellhousing mystery hole

Post by BEEK »

the" square headed bolt to nowhere" and the threaded hole are for the fitting of an exhaust bracket from the underside on the 79 up spiders
Automotive Service Technology Instructor (34 year Fiat mechanic)
75 spider
, 6 Lancia Scorpions, 2018 Abarth Spider, 500X wifes, 500L 3 82 Zagatos. 82 spider 34k original miles, 83 pininfarina, 8 fiat spider parts cars
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