Rear axle swap/upgrade - 6 lug

[muddybuddy]

Not being able to go back to 15’s isnt a deal breaker, i was just hoping it would still be doable. I’d rather have bigger and better brake setup and stick to 17’s.

As for gearing, ultimate plan for the truck is a more modern trans, currently undecided between a manual or 6-10spd auto.

Appreciate everyones input thus far

 

[AJMBLAZER]

Do any parts swap between the GM 9.5" (14B s/f) and the '14+ 9.5" (which I assume is AAM)? You know, axle shafts, gears, lockers, etc. I know there are some parts you can use from the RAM 9.6" front diff and I believe that's all AAM.

Yes, but it’s complicated. If you look in the AAM manuals a lot of things like shafts and bearings are the same. I’ve read where guys have put in 14SF lockers by mixing and matching the diff parts so everything lined up.

This is a good point. New trucks have 10-speed transmissions with super low first and double overdrive, so they tend to have weeny differential gears compared to what we run in old trucks, so gear swap or doubler expected.

Yep. My ‘11 with 3.42’s and my ‘19 with 3.23’s get up and scoot. Gotta love super low first gears and 2-3 OD’s. Hell, the 6L80E doesn’t even have 1:1 gears. Everything has reduction or is OD.

Not being able to go back to 15’s isnt a deal breaker, i was just hoping it would still be doable. I’d rather have bigger and better brake setup and stick to 17’s.

As for gearing, ultimate plan for the truck is a more modern trans, currently undecided between a manual or 6-10spd auto.

Appreciate everyones input thus far

Love my 6 and 8 speeds. Pretty impressed with the wife’s 10 speed so far.

 

[muddybuddy]

So I’ve found a newer 10b w/ factory disc and parking brake and a newer 14sf/9.5” w/ factory disc and parking. Both seem to be 67-69” WMS, which is exactly what I’m wanting. Decision is do I leave my 6 lugs behind and swap to 8 lug? Both are the right gears so thats not an issue and both will require perches and shock mounts. Guessing the 15” rallies wont fit over the disc anyways.

What are the lowest numerical gear set for the newer GM 14sf/9.5”?

Pic of the potential 9.5” 8 lugger. Has 3.73’s and G80

 

[Chevy305]

My '12 Silverado has the factory 6 lug 14bsf with disks and I can assure you that 15" wheels do not fit over the calipers, I've tried.

If you are dead set on keeping your wheels you can find a 6 lug 14bsf from a GMT400 with drums. They do fit 15" wheels without issue.

 

[Blue85]

You can go down to 5:13 on 14b s/f. Most people don't recommend it for 10b due to the small pinion, but you probably don't want to go that deep anyway.

I would go deeper than 3.73, though.

 

[muddybuddy]

My '12 Silverado has the factory 6 lug 14bsf with disks and I can assure you that 15" wheels do not fit over the calipers, I've tried.

If you are dead set on keeping your wheels you can find a 6 lug 14bsf from a GMT400 with drums. They do fit 15" wheels without issue.

Yea i think im past the 15’s. Thought would be cool to keep them and swap them on to feel nostalgic when I want to, but plan to go to 17’s anyways and would rather have better axle and brakes than be able to fit 15’s back on (in reality, may never get swapped back on).

Just a matter of whether to try to stick to 6 lug or convert to 8. Guess I’ll just have to nail down wheel section and go from there

 

[nitro_rat]

What are the lowest numerical gear set for the newer GM 14sf/9.5”?

I’m pretty sure that 3.42-5.38 are available.

 

[Chevy305]

Yea i think im past the 15’s. Thought would be cool to keep them and swap them on to feel nostalgic when I want to, but plan to go to 17’s anyways and would rather have better axle and brakes than be able to fit 15’s back on (in reality, may never get swapped back on).

Just a matter of whether to try to stick to 6 lug or convert to 8. Guess I’ll just have to nail down wheel section and go from there

The real question is, do you ever plan on upgrading the front to a D60? Or going big enough that you'll swap a 14bff in the rear? If you're even thinking about it, just go 8 lug now. If you have no plans on going bigger, I'd get the rear end that makes the most sense money wise and plan out from there.