Stupid 10 bolt

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Joe Dirte

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So it kinda hit me yesterday. I put a low mile 4L80 in my 98. I'm thinjin 25k miles. Well I was thinjikin reverse took a dump on me. Seemed odd. Then last nite while playin musical trucks on my property I thought about my overlooked "roundtoit" issue. The rear axle will randomly lock the rear tires in reverse. I shift into reverse it engages strong n can feel the truck lurch, but it doesn't wanna move, but once I get it movin it responds great to throttle til the axle locks n skids. It's the original high mileage non-G80 10 bolt. I'd heard that I think was the center pin slides out for one reason or another n jams into housing. I'm starting to think my reverse issue is actually a differential issue. I could be way off but just thinkin thru before I go n rebuild a possibly good 4L80 when I have a good G80 14b SF sittin here, ready to be bolted in. It was a city water parks truck and dude drove it over 2hrs home before we took trans out so that's also part of my reasoning.
 

Joe Dirte

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What are you waiting for? :drool:
Finding a matching front diff. Goin from 3.42s to 3.73s. Maybe this week I'll hit up yard. Can probly get one for $50 since they sold me the 14b for $100. Gonna go to semi shop tmrw after work n get u bolts.

Plus was hopin I'd get reverse "working" as the axle never crossed my mind. Didn't think about "hey if I drive to work I'm probly gonna need to back out of somewhere at some point." Naaaaw... that won't ever happen. Haha
 
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Schurkey

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Pull diff cover n see. Good time to change fluid.....
If a 10-bolt, 8.5" rear axle in a full-size truck needs the fluid changed...it's totaled and should be replaced.

GM had no business stuffing the 8.5 under a full size truck. The axle was originally designed for small-block and six-popper compact and intermediate cars, because even compacts and intermediate cars with big-blocks got the "12-bolt" car axle. Even with the axle-shaft upgrade from 28 to 30 splines in '89 (?), it's just not tough enough.

And then there's the matter of the horse-shiit 254mm rear drum brakes that came with most of the 8.5" axles.

What are you waiting for? :drool:
Yup. Just don't use 4WD until you get the front diff changed.
 

Joe Dirte

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Hopefully gonna start on this today after escalade is done. Got woodburner goin to warm up garage. Gonna suck not havin 4wd for a bit but if it fixes my reverse issue and I can go haul next year's firewood I'll be happy.
 

someotherguy

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If a 10-bolt, 8.5" rear axle in a full-size truck needs the fluid changed...it's totaled and should be replaced.

GM had no business stuffing the 8.5 under a full size truck. The axle was originally designed for small-block and six-popper compact and intermediate cars, because even compacts and intermediate cars with big-blocks got the "12-bolt" car axle. Even with the axle-shaft upgrade from 28 to 30 splines in '89 (?), it's just not tough enough.

And then there's the matter of the horse-shiit 254mm rear drum brakes that came with most of the 8.5" axles.


Yup. Just don't use 4WD until you get the front diff changed.
It's why I was excited to get the '94 C2500LD and then later the '06 SS. Both with the 9.5" 14 bolt.. although the '94 came with the 2500 insurance penalty. Go figure. It was easy to compare with a '94 C1500 5.7 on the same policy with the '94 C2500LD 5.7, the 2500 cost me significantly more for no good reason.

Richard
 

smdk2500

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It's why I was excited to get the '94 C2500LD and then later the '06 SS. Both with the 9.5" 14 bolt.. although the '94 came with the 2500 insurance penalty. Go figure. It was easy to compare with a '94 C1500 5.7 on the same policy with the '94 C2500LD 5.7, the 2500 cost me significantly more for no good reason.

Richard
I have the same issue with my 95's. Both are 2500's 4x4 long boxes the only difference besides engines is one is a regular cab and the other is a extended cab. The extended cab is 5-6 bucks more a month then the regular cab. I asked why and they said that extra 2ish feet of cab is what made the difference.
 
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