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Discussion Starter #1
I am looking at swapping a 12 bolt (from a 76 chevy truck- 2WD) into my 84 stepside (2wd). Does anyone know what problems I might encounter. I assume that they should be almost identical?

My second question is how do I identify the axle numbers on the 12 bolt. I have been looking for a document that will decode chevy truck axles, but have not found anything. The only site I found was one that decoded Camaro Axles - are they the same for decoding???


Thanks in advance for any help you provide.

cheers:confused:
 

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try the classic chevy & gmc pickup message board. its a wealth of info for our trucks
 

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I put an '84 10-bolt truck rear in my '79 Suburban (originally a 12-bolt) last year. The 10-bolt rear has a longer snout, & needs a driveshaft 3/4" shorter. You'll need a 3/4" longer shaft to convert to a 12-bolt. If I remember correctly, the driveshaft from my donor truck ('84 LWB with 10-bolt) measures 70-1/8" from center-to-center of the U-joints.

You'll also need a conversion U-joint, because the 10-bolt truck uses a larger U-joint. I got mine from NAPA, but I don't know what the part number was, because he was out of them & he took parts from 2 different U-joints & made me one.

The Suburban had bigger brakes, and the parking brake cables were set up differently, but they swapped out easily. Just pull the axles (replace seals & check for bearing grooving while they're out), unbolt the backing plates (cable & all), and swap them.

A good Chevy truck site is www.67-72chevytrucks.com . They have message boards that cover 1947-1998 Chevy trucks. Other good sites are www.73-87.com , and www.73-87chevytrucks.com

Oh yeah, I dribbled used motor oil all over the spring U-bolt nuts & shock nuts about a week before I did the swap. Makes it easier to undo them.
 

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Discussion Starter #6
Reason for changing

I was going to convert the 10 bolt to a posi unit, until I came across a fellow selling a 12 bolt posi. The price was the main reason (only $125) and I thought the 12 bolt would stand up better than the 10 bolt. The truck I am putting this in is a 84 stepside short box, I will have to exame the U - Joints and axle lenth to see how much modification this requires.

thanks for the info
 
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