Couple simple tranny questions - 69 Coronet

[beanhead]

Thanks, guys. I just now had a minute to look at the rear end. No bolt on differential cover. It looks welded on from the factory. There is a big serial number on the driver side of the yoke cover ? Can’t quite read it until I raise the car.

8-3/4. You're seeing the casting #. Last digits will be 741, indicating the smaller pinion and u-joint series(7260). If by some chance it ends with 489 or 742 you've scored and it's the large pinion and u-joint(7290). Either way you can verify the gear ratio by jacking up the rear, putting it in neutral and counting how many times the pinion yoke/driveshaft turns during one complete turn of the rear wheel. 2 and about 3/4 of turn of the yoke is a 2.76 ratio, 3 and about one quarter is a 3.23 and so on.

 

[Fran Blacker]

742's came with a 1330 large yoke for a few years.

 

[pearljam724]

Thanks guys, immensely. I ll check it out. I don’t know at this point what it means that I saw. But, one thing I definitely noticed and stuck out. Was how big the yoke, drive shaft and u joint appeared to me. My first thought, “ wow that’s a big diameter drive shaft and u-joint. My car sits lower than I’d like because it needs rear springs and it has 14” magnums. I was on the driver side of differential and couldnt find a filler hole either ? But, I didn’t look on passenger side because I was in my back and it started to rain a little.

 

[beanhead]

The filler hole is on the passenger side, you'll see the plug next time you get under there. Good luck!