Pinion yoke fit

[zakimodo]

Hi All

I am building a new 489 center section to replace the 741 unit unit that is in my car today. The 489 case I have was empty when I received it. I have rebuilt other differentials (mainly heavy equipment rather than automotive) but never an 8 3/4. Without the luxury of taking one apart, I have a question regarding how tight the pinion yoke should fit on the pinion.

I am test fitting all my parts before final cleanup and assembly and noticed that the pinion yoke fits tight and seems to have a slight taper. I believe this is correct as this taper is what seals oil from leaking around the splines. If this is not the case please let me know.

Also have a question regarding the correct dimensions for the carrier cap bolts. Mine have a little corrosion on them. I haven't found a source for replacement hardware.

 

[john-9]

the pinion yoke is usually a light press fit but have seen plenty that just slip on -- there is no taper to the yoke splines --- a light application of some silicone to the splines .
will prevent any seepage of gear lube.
as far as hardware such as carrier cap bolts any Grade 8 1/2 inch X 13 thread bolt the length of the originals will work --- best place to buy your bearing kit along with any shims , ring gear bolts etc, is from Ratech Manufacturing -- you can probably order direct from them or Summit Racing carries all their kits and parts.