904 help

[chargd72]

I have zero knowledge on transmissions but I'm at the point that I need to learn.  I was under my car the other day and noticed a big open hole (Big red circle) with a loose retaining clip (small red circle).  What is this and what is supposed to go in there???

Thanks for any help.

[jlatessa]

Speedometer cable

[chargd72]

Thanks!  I thought the Green Circle was the for the speedo.  Any idea what that sensor might be for?

[John_Kunkel]

The part circled in green is the Neutral Safety Switch (on '69 and later it also acts as the backup light switch). The part circled in red is pictured below.

[chargd72]

Thanks John   
Can you give me the names of those pieces so I know what to start searching for?

[chargd72]

Weirdest thing.  I was looking in a random box for my bypass hose and look what was in there.  Previous owner must have given it to me in one of his misc parts boxes.  Thanks again for posting that picture.  Would have looked right past it if you didn't.     

[Troy]

The speedometer gear (pinion) is interchangeable to match whatever rear end gear you have (the housing is the same). That one looks pretty small so if you have changed gears you'll need to buy another so you're speedometer isn't way off. They are generally listed by color or teeth on eBay but most of the part numbers are still good at the dealer.

Troy

[chargd72]

The speedometer gear (pinion) is interchangeable to match whatever rear end gear you have (the housing is the same). That one looks pretty small so if you have changed gears you'll need to buy another so you're speedometer isn't way off. They are generally listed by color or teeth on eBay but most of the part numbers are still good at the dealer.

Troy

Good info, thanks!  I have yet to do the tire test but I think it has the stock 2.76 gears in now.  I'll make sure they match before I proceed.