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Old 09-28-2007, 05:46 PM   #1
RicksTrucks
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Changing out differential - need advice

I picked up a 3.08 and would like to put it in my 68 Short stepside (350/3 speed on the floor) to see if I can get better mileage and it not get so wound up going down the highway. Had it up on the rack last nite replacing the shocks and noticed the pumpkin was hot after a 30 mile drive. (I know the fluid probably could use a refreshing.)

Is there an easier way to do this rather than exchanging the whole rear end?

Can I just take the stuff out of the pumpkin and if so what are the steps? Advice would be appreciated.
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Old 09-28-2007, 06:07 PM   #2
1969k10stepside
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Re: Changing out differential - need advice

You can remove the ring,pinion,and carrier from one and swap it in the other but installing the gears involves being precise and you need the right tools for the job.Anyone with a manual,the correct tools,and the time can do it though but not setting things up perfectly can cause pre-mature and excess wear.
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Old 09-28-2007, 06:11 PM   #3
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Re: Changing out differential - need advice

special tools, special know how, Way easier to swap axles.
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Old 09-28-2007, 06:15 PM   #4
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Re: Changing out differential - need advice

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special tools, special know how, Way easier to swap axles.
x 2,
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Old 09-28-2007, 06:25 PM   #5
mvfd70
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Re: Changing out differential - need advice

yup what they said. I just had the gears replaced in my 72 axle going under my 68. The Pinion was broke on it so I had to replace it anyway. The pinion has to be pressed out and the bearings pressed off. Then new bearings have to be pressed onto the pinion, a new crush sleeve put on, and the pinion pressed back into the pumpkin. Then the yoke has to be tightened to the proper specs so that the pinion turns at the right torque (supposed to use an inch/pounds torque wrench to test that). It was just soooo much easier to let someone with the right tools and way more knowledge than me to rebuild it.
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Old 09-28-2007, 06:59 PM   #6
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Re: Changing out differential - need advice

What about pulling the whole assembly off from the front, leaving the pinion, ring gear and all untouched? 10 or 12 bolts holding the whole thing to the axle and swap the whole assembly over. Slide your axles back in and your done, or am I missing something?
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Old 09-28-2007, 08:19 PM   #7
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Re: Changing out differential - need advice

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Originally Posted by Ace in the hole View Post
What about pulling the whole assembly off from the front, leaving the pinion, ring gear and all untouched? 10 or 12 bolts holding the whole thing to the axle and swap the whole assembly over. Slide your axles back in and your done, or am I missing something?
The 1/2 ton Chevy rearends don't come apart like that. You have to disassemble the whole setup.

The problem with setting up a used ring & pinion in a different housing is that the have already established a "wear-in" to each other. It is almost impossible to get EXACTLY same position, so usually you end up with early failure. If you have he whole rearend, I'd swap it out.
Its may seem like more work, but it is WAY less technical, even if you were putting in new gears. It's even more difficult to get used gears right on.
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Old 09-28-2007, 09:11 PM   #8
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Re: Changing out differential - need advice

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The 1/2 ton Chevy rearends don't come apart like that. You have to disassemble the whole setup.
Ahh, that makes sense now, I am not up on 1/2 ton stuff. I just took apart a 3/4 ton axle with 4.11 gears. Thought I would keep it as a whole to bolt right in, in case I ever want to change my 4.56 out. The downer to this would be I would have to change the front axle gears to match if I want to use my 4wd.
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Old 09-29-2007, 01:14 AM   #9
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Re: Changing out differential - need advice

3.08 gears and a 3 speed manuel tranny ? 1st gear take offs are gonna be a major clutch slipper. forget hauling loads and pulling a trailer........ if your gonna run the 3.08,s install a sm465 ,4 speed manuel so you,ll get granny first gear to get it moveing....
bob
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