Differential rebuild; any "while you're at it..." useful suggestions?

[RC92234]

Grinding and a leak = rear end rebuild.  Thought I'd ask if there are any "While you're at it, it would be good to do..." suggestions.  Already have checking the u-joints once the diff is opened up and axle seals.  What else?

Also, currently have 3.25 gears (351C-4V, C6) which means about 2600 rpm at 55 mph; my guy says won't even feel 3.00 gears but will reduce rpm and improve mileage.  Your thoughts?

 

[71mach351]

I replaced my 3.25 open with a 3.50 trac loc.  I felt the 351 4v with c6 and stock converter was a dog off the line.  3.50s did liven it up a bit. Definitely replace u joints while the drive shaft is out.  New axle bearings, too.

 

[Sheriff41]

Virtually no benefit to gas mileage going with a 0.25 higher gear.  I'd stick with the 3.25s if you are happy with the current performance.  I second Rick's comments on the other bits.

 

[Bentworker]

I’d do axle bearings while you are at it.  Maybe the brakes?  Send the driveshaft out to have the balance checked post u-joint replacement?  If you pull the housing use new u-bolts.
 

Chromoly axles?  31 spline axles and carrier?  Save some weight with an aluminum 3rd member?  Nodular iron 3rd member for strength?  Maybe a torque biasing or limited slip differential?  If you hate yourself how about a Detroit locker?  Maybe upgrade to 1350 size yoke?  How about a new driveshaft to pair with that larger yoke, maybe carbon fiber or aluminum?  How are your rear springs / shocks?  Maybe some sort of traction bar?  Coilover system?

 

[Tnfastbk]

https://spicerparts.com/calculators/engine-rpm-calculator

This will allow you to see the rpm change with each ratio change. 

 

[Duncan Mach72]

31 spline axles and carrier? Maybe a torque biasing or limited slip differential?

That's what I did to mine & I'm very happy with the torque biasing diff, much better on the road than a traction-loc (limited slip) or open diff.
I'm not convinced the 31 splines are necessary for the road but I wanted to take mine on the strip with a 429 & Quick Times.

 

[InjectedMach]

Eaton True Track torque biasing diff as already suggested.