8 3/4 pinion splines

[demonmike70]

So ,I finely got around to disassemble my 741 housing. The new ring and Pinion has 29 spline pinion, as all the parts catalogs show. But mine has a 10 spline pinion .
I measured the Pinion thickness, both old and new are 1 3/8 thick anyone ever run across this before?

 

[Locomotion]

I'm guessing that the coarse spline pinions tend to be aftermarket, which may be cheaper to make. But I've seen it with other housings also. It usually says which spline it is in the sales ad.

 

[demonmike70]

I'm guessing that the coarse spline pinions tend to be aftermarket, which may be cheaper to make. But I've seen it with other housings also. It usually says which spline it is in the sales ad.

All 741 pinion are suppose be 1 3/8 with a 29 spline Pinion according to every parts manufacturer I've found. That's why I can't figure this one out.

 

[crackedback]

The lower pinion in your picture isn't a 741 case pinion.

That's a 742 case pinion.

 

[33IMP]

The lower pinion in your picture isn't a 741 case pinion.

That's a 742 case pinion.

Are you sure? Looks like a 741 with a spacer on it to me.
There are basically four stock Mopar 8 3/4 rearend yokes. Big and small u-joint, and coarse and fine spline.
The yoke needs to match your gears and u-joints.

 

[Locomotion]

Moparts on the Web - Main Index

 

[sabre67]

subscribed

 

[oldkimmer]

741s had coarse splines from the factory till 1970. Then fine spline till 74. Yes almost all aftermarket gears are fine spline. Kim

 

[Oldmanmopar]

742's are 10 spline, 489's are 29 spline, 741's can be both 69 and earlier are 10 spline. 69 and later are 29 spline. split year. You forgot to see what year your rear was before ordering. You will need to buy a later yoke from Dr. Diff

 

[str12-340]

Let's stop guessing

742 - (1964-72) 1 3/4 pinion coarse spline
741 - (1964-69) or 657 - (1957-64) 1/3/8 pinion coarse spline
(1969-72) 1 3/8 fine spline
489 or 488 - (1969-74) 1 7/8 pinion coarse or fine spline

While I'm at it:
Sure-Grip - Dana PowerLok (clutch style) 1958-1969
Borg Warner Spin- Resistant (cone style) 1969-1974

 

[str12-340]

If you get a fine spline yoke be sure you get one for the right U joint