10 bolt upgrades ("big" 8.5", 30 spline, w/big axle shafts and big wheel bearings)

[shovelbill]

Don't know what part of CT you're in, but check out these yards. DeMilo's (HTFD), A&B (E.HTFD), and Tom's (Bristol). Each yard has a 9.5" 3:42 gear rear. I'm in Manchester btw

A few years back, when I was going to do my upgrades, almost all the 9.5s I had found were G80 3.42s as well. I speculate they were F44 diesel rears. They sure weren't expensive as I recall, and I also have 3.42s.

 

[caw_86]

Yep. I waited over a year with my truck broken waiting to find a 14bsf but no dice. Only came across a few 14b ff that needed completely rebuilt which would have cost more after it was all said and done. Shops around here (Spokane, Wa) charge a minimum per job and not the actual time spent, unless it goes over the quoted "job time". I was quoted 6 hrs to replace 4 glow plugs in my box truck and I was told I would pay for 6 hrs even if they got them done in 45 minutes. I changed them myself in THREE MINUTES.

Things in the real world are spendy. I wish I could get things done for what other online say they can. Even if I do the work myself, the parts are usually just as spendy as what a whole project cost other people.

yeah its gets real expensive real quick, my shopping cart is getting out of control

front and rear 4.88 ring and pinion $636
front and rear beaing kits $250
rear carrier yukon LSD $358
14 bolt SF axle assembly $75, came with no carrier or shafts
axle seals $120
rear axle shafts $250
air compressor and media blaster $600
paint $200
NBS rear disk brakes $670
thank god autozone has a rent a tool program, special tools are crazy expensive, looking like ill need a get 100 tool for the front diff though

 

[Supercharged111]

A few years back, when I was going to do my upgrades, almost all the 9.5s I had found were G80 3.42s as well. I speculate they were F44 diesel rears. They sure weren't expensive as I recall, and I also have 3.42s.

I dunno, my dad had a 6.5 and it was a 4.10 (but also 8 lug). Not sure they targeted fuel economy with those motors? I realize a sample size of 1 is a bit small to base GM's mindset off of, but I'm also thinking along the lines of how they rated these trucks for towing in the owner's manual too. Could be wrong.

 

[shovelbill]

I dunno, my dad had a 6.5 and it was a 4.10 (but also 8 lug). Not sure they targeted fuel economy with those motors? I realize a sample size of 1 is a bit small to base GM's mindset off of, but I'm also thinking along the lines of how they rated these trucks for towing in the owner's manual too. Could be wrong.

I met a guy recently who ordered his 1500 diesel and ordered it with 3.42s to keep the cruise rpms down, where the diesel wanted to live most of its life. I agree on the lower ratios for towing, of course.

 

[RichLo]

yeah its gets real expensive real quick, my shopping cart is getting out of control

front and rear 4.88 ring and pinion $636
front and rear beaing kits $250
rear carrier yukon LSD $358
14 bolt SF axle assembly $75, came with no carrier or shafts
axle seals $120
rear axle shafts $250
air compressor and media blaster $600
paint $200
NBS rear disk brakes $670
thank god autozone has a rent a tool program, special tools are crazy expensive, looking like ill need a get 100 tool for the front diff though

Air compressor and blaster $600 ??
Paint $200 ??

Planning on full automotive primer/base/clear and wet sanding out the orange peel on that axle?

 

[caw_86]

Air compressor and blaster $600 ??
Paint $200 ??

Planning on full automotive primer/base/clear and wet sanding out the orange peel on that axle?

its a junkyard axle, needs good cleaning and de rusting

 

[shovelbill]

its a junkyard axle, needs good cleaning and de rusting

I have found, with my projects that are mostly Harley related, not that it matters, that a good session with a wire wheel and a quality rust converter works well prior to the proper paint for the application. I wish I could do that to my frame.

 

[shovelbill]

I dunno, my dad had a 6.5 and it was a 4.10 (but also 8 lug). Not sure they targeted fuel economy with those motors? I realize a sample size of 1 is a bit small to base GM's mindset off of, but I'm also thinking along the lines of how they rated these trucks for towing in the owner's manual too. Could be wrong.

Also. 3.42, 4L70, 265/17s...I had around 800 pounds in the bed, the trailer full, and it was probably 4,500 pounds extra weight in total. My 383 barely knew there was anything out back, and I never had to shift to third. Over 275 miles, including the two hours to get out of NYC, she averaged 11.5ish mpg as well. I know it's not a lot of weight.

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For where I live and how I would use this truck, I would do 3.73s if I go to a 33" tire. I know the engine makes quite the difference.

 

[Horntoad]

Don't know what part of CT you're in, but check out these yards. DeMilo's (HTFD), A&B (E.HTFD), and Tom's (Bristol). Each yard has a 9.5" 3:42 gear rear. I'm in Manchester btw

Thanks! I'm in Enfiield.

 

[Horntoad]

So... I believe the 11" drums on the 10 bolt only came with 7200lb GVWR (this is from the service manual and other sources) and that, for Tahoes and Yukons, that is only 4DR.

If I were going to have to go with a new axle to fit the 11" drums, I also did some more fact finding on weight of the axles. For reference I looked at the Zumbrota RAA435-1652B 10 bolt (it's for a 4DR and thus fits 11" drums; yes it's a 3.73, but bear with me) and at the Zumbrota RAA435-1524B 14 bolt (these open-diff assemblies do not include hubs, backing plates, axle shafts, or brakes). The 10 bolt weighs 260 lbs. The 14 bolt weighs 280 lbs. I looked at this a couple different ways, just to be sure, with 3.42 axles, and the weights, not surprisingly stay the same as I quoted here previously.

Of course the bigger 1.37" axle shafts in the 14 bolt (versus the 1.31 in the 10 bolt) are going to weigh a little more. Let's continue this exercise. For reference I used a Richmond 92-25148 (1.37", 33 spline) and a Richmond 92-25115 (1.31", 30 spline). The weights for these single shafts (with bearings, seals, and lugs) are 25 and 20 lbs, respectively.

Looks like (let me know if I'm missing something) the 14 bolt with axle shafts weighs 330 lbs and the 10 bolt with axle shafts weighs 300 lbs. The brakes weight should be the same for both.

So is the weight difference between the 14 bolt and 10 bolt, each with 11" drums, only 30 lbs! Add in the Detroit True-Trac (913A481, 26 lbs; 914A538, 44 lbs) and that ups the weight difference to only 48 lbs. (I had seen somewhere that the 14 bolt was nearly a couple hundred pounds heavier.)

As always, experience, insight, and constructive comments are appreciated.