Noticed mine is broken. Went to the junkyard and everytime I tried to get one the plastic broke due to it gets fragile over time. Does anyone know a part number or can I use one from an older rear - say the 8 1/2 rear - or any tricks to help with this? Thank you very much.

Do you have the 10 bolt or 9 bolt? The 9 bolt uses the same vent as the Mustang 8.8. The 10 bolt uses a plastic press in vent that can usually be easily removed by holding it at the base with pliers and turning it while pulling up. I have some new ones in the shop, but I can't remember the part number.

Big Gear - thanks for the reply. It is a 10 bolt. I tried the pliers at the bone yard but they break due to the plastic gets hard and brittle.
If you have some at your shop, do most shops? Or would you be willing to sell one of yours?
I see some advertised in the Classic Ind catalog, but they are for either 7/16 or 3/8 (both press in) and are for the older style rears so didnt know if one of these could be used.

I keep them because I build rear ends. That's about all that I do (and a few manual transmissions). I have the old 3/8 and the 7/16 vents, and I will sell you one. Check yours and see what size it is. I think I sell them at about 1/2 the price of the resto parts places.

Big Gear. I measured and believe it is a 7/16. How much would one be?

I'll try to remember to check the price tomorrow. I think it's about $4 or $5. Takes about $4 to ship.

Thanks, just let me know.

It's $3.60.