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Old 09-28-2020, 10:56 AM   #1
blazer2007
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88-98 rearend in a 78 1/2 ton ?

I read that a 88 rear is about 1 inch wider than a 78 which would look good pushing the back tires out abit. I sure you would have change spring pads, Just wonder who has done it. Are the 88 style rearends any good?
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Old 09-28-2020, 11:42 AM   #2
kwmech
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Re: 88-98 rearend in a 78 1/2 ton ?

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Originally Posted by blazer2007 View Post


Are the 88 style rearends any good?
Not really, probably going to be a 10 bolt--- with a gov-loc. Any more than stock horsepower and lots of miles on is guaranteed destruction unless the first thing you do is rebuild it. Even at that it is just not a rear axle that belonged in a truck
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Old 09-28-2020, 05:31 PM   #3
SCOTI
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Re: 88-98 rearend in a 78 1/2 ton ?

The 88-98's are a corporate 10-bolt just like it's predecessor; only wider. 10-bolts are not in the realm of 'HD' strong from the factory but can be built for abuse.
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Old 09-28-2020, 08:53 PM   #4
Ziegelsteinfaust
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Re: 88-98 rearend in a 78 1/2 ton ?

Like said above it is a box standard 8.5 10 bolt, but i say it is a good rear-end for a true rated 1/2 ton. My 2018 does fine with the slightly upgraded 8.6 10 bolt. Mind you I only have 28,000 miles, but i have faith. Plus there cheap to rebuild or upgrade.

All semi floaters the outer bearings take a beating if uses hard, and they should be checked. Or atleast the wheels wiggled to see if you can feel to much play.

If I were to replace a 8.5 10 bolt in a 1/2 ton, and if for what ever reason. On a budget it would be a brand F 8.8, and money 💰 no issue it would be a 9 inch. The 12 bolt would only be for some 100 point resto. It cost alot, and offers no advantages at its price point. With my limited skill I could build a epic 8.8 for just over 1/2 what a new 12 bolt costs, or what a used one cost typically.

Either way I would use a main cap support cover like this.
https://www.jegs.com/i/Moser/718/710...IaAre4EALw_wcB

Every rear end I tore up or all 4 of them was be cause the main caps walked under pressure of my ignorance. Every rear end I had with a cover lasted through my stupidity. These were not race vehicles, but me doing what ever for fun.

I do like the wider axle idea because I love flush fitting tires.
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Old 09-28-2020, 08:56 PM   #5
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Re: 88-98 rearend in a 78 1/2 ton ?

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Originally Posted by Ziegelsteinfaust View Post
I do like the wider axle idea because I love flush fitting tires.
Is there any concern with reduced turning radius?

I'm doing something similar, in switching a 9.5 14-bolt for a 2001 10.5 14-bolt. The wheel mounting width will be two inches wider.

I was told that GM intentionally narrowed up the rear wheels to improve low-speed maneuverability. Will I be compromising that by using a wider rear axle?
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Old 09-28-2020, 09:07 PM   #6
blazer2007
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Re: 88-98 rearend in a 78 1/2 ton ?

Thanks ,I thought maybe they had improved the 88 rear from the 81-87,but guess not.
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Old 09-28-2020, 11:50 PM   #7
Ziegelsteinfaust
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Re: 88-98 rearend in a 78 1/2 ton ?

Quote:
Originally Posted by kipps View Post
Is there any concern with reduced turning radius?

I'm doing something similar, in switching a 9.5 14-bolt for a 2001 10.5 14-bolt. The wheel mounting width will be two inches wider.

I was told that GM intentionally narrowed up the rear wheels to improve low-speed maneuverability. Will I be compromising that by using a wider rear axle?
Yes, but not that much as taller tires would do to you.

On my 74 C20 with a 85 C20 14 bolt semi floater. When I added 2 inch spacers to the rear, and 1 inch spacers in the front. For the flush look, but still have full compression. It roughly added 3 foot to a U-turn.

When I converted my truck to 4x4 I went from roller 245/70r16' to new 285/75r16, and it gained over 5 foot. With the exact same rims, and spacers. Going off memory hear.

I have heard that too, but I never thought to do any testing . Also I have heard they didn't want the tires riding in the same "rut" for lack of the proper term.
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Old 09-29-2020, 03:58 PM   #8
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Re: 88-98 rearend in a 78 1/2 ton ?

The '88 and up are 30 spline Vs. 28 which should make them a little stronger. For whatever that's worth. I have the '88 axles and carrier in my '84 10 bolt. If I remember correctly the axles were about 7/16" longer which does push the wheels out a bit. I have not noticed a difference in the turning radius, which wasn't great to begin with.
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