diff gear change

[63SplitWindow]

I have an 8.75 rear diff (742) that has 4:56 gears with a spool. I want to change the gears to a 3:23 and keep the spool. Can I re-use the spool setup with a new gear set?
Any recommendations as to what manufacturer gear set to use? This diff will be abused

 

[JARRETT LYNCH]

Yes, you can, but you will have to replace the pinion and ring gear which means you will have to set up pinion depth and backlash and pre load. Its not super hard but you have to know what you're doing. I would go with tried and true Richmond gears.

 

[496 polara]

Mopar 8 3/4" (8.75) Ring and Pinion for 741, 742, or 489 case

Richmond were always noisy to me. Strange/US Gear or Dr Diff would be where I looked.

 

[j-c-c-62]

A 3.23 is a nice street gear. A 4.56 with a spool is a bad *** strip gear combo.
A spool on the street does not have the best street manners, why are you keeping it with a street gear, vs any other solutions available?
How does one abuse a 3.23 that replaced a 4.56? Its commonly thought a larger/higher pinion tooth count makes a R&P ratio stronger

 

[Rishi]

If you ever think you want to swap the 4.56 back in, for a track event or whatever, it is simpler to swap out the whole 3rd member assembly. it is what the 8.75 seems designed for. the cost of 3.23 sure-grip/spool is not that high, compared to other changes and time spent swapping.

 

[john-9]

first off ,, Richmond Gear exists in name only since they were bought out by Motive Gear about 10 or more years ago ,, you can still get a Richmond box but it will have a Motive Gear in it ,, Motive Gear dropped 3.23 gear sets from their product line ,, US Gear does not exist anymore since covid again bought out by someone ,, only 3.23 gears sets out there now are Yukon Gear (made in China ) and Doctor Diff may have a 3.23 gear sets ( made offshore as well ) and some off brands such as Nitro etc. from parts unknown.

 

[JARRETT LYNCH]

The real question is why would anyone want to drive on the street with a spool? You're gonna tear stuff up. Just buy a good used third member with an open diff or posi. Then if you want to go racing just swap it out. Thats what I'd do.