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S10 4x4 Blazer rearend vs. S10 2wd rearend

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Old 02-12-2014, 09:20 AM
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Default S10 4x4 Blazer rearend vs. S10 2wd rearend

I have a '51 Chevrolet rat truck mounted on an S10 frame (2wd) and the rearend seems too narrow , I know that the 4x4 Blazer rearends are wider , my question is: Are the leaf spring perches in the same location on a 4x4 Blazer and a common 2wd pickup? Will the 4x4 rearend be a direct bolt up as far as the springs? will the 4x4 rearend set on the centerpins of the 2wd frame and springs? , thanks in advance...
 
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Old 02-12-2014, 09:33 AM
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The spring perches are the same width, and are on the same position on the axle. The Blazer perches will also have a cup on the back for the rubber bump-stop that's on the frame. The S10 pickups don't have this cup, but it won't affect anything if you have it or don't. The axle swap should be a direct bolt up and is pretty easy to do, but make sure you're getting a normal 4x4 axle and not a ZR2. The normal 4x4 axle is about 3-4" wider than the 2wd axle. The ZR2 axle is around 6-7" wider than the 2wd axle.
 
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Old 02-12-2014, 11:19 AM
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Originally Posted by El_Beautor View Post
The spring perches are the same width, and are on the same position on the axle. The Blazer perches will also have a cup on the back for the rubber bump-stop that's on the frame. The S10 pickups don't have this cup, but it won't affect anything if you have it or don't. The axle swap should be a direct bolt up and is pretty easy to do, but make sure you're getting a normal 4x4 axle and not a ZR2. The normal 4x4 axle is about 3-4" wider than the 2wd axle. The ZR2 axle is around 6-7" wider than the 2wd axle.
I am taking the rear end ou of a 1998 GMC Jimmy , I wish I had a ZR rear end , I want to use a set of 10' wide rims and tires , I think the rearend I have will work , but I know the ZR rear will , thanks alot..
 
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Old 02-21-2019, 10:44 AM
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Originally Posted by El_Beautor View Post
The spring perches are the same width, and are on the same position on the axle. The Blazer perches will also have a cup on the back for the rubber bump-stop that's on the frame. The S10 pickups don't have this cup, but it won't affect anything if you have it or don't. The axle swap should be a direct bolt up and is pretty easy to do, but make sure you're getting a normal 4x4 axle and not a ZR2. The normal 4x4 axle is about 3-4" wider than the 2wd axle. The ZR2 axle is around 6-7" wider than the 2wd axle.
Hello. I'm looking for a 59-60 inch rear axle for my 51 chevy car. I believe the S10 4x4 fits this right. But does it matter if it's a Blazer instead of a Truck? I am getting conflicted reports. I want an 8.5 ring gear (not the 7.5) and a 3.42 ratio. Which S10 would work? I'd even prefer the drum brakes for the back.

Can you help me know what year, make and model I would need to search for? Some people say the 95 and newer. Others tell me the early 80s S10 and GMC 215. Others say the axles without the ZR2 can work but what you say here seems like it wouldn't. My biggest issue is making sure the axle is the right width and that is the hardest part to know for certain. I can find axles online that are S10 with 8.5/3.42 but I keep finding conflicting info that makes me wonder if it's really 60 inches.
FOR EXAMPLE: I am looking at a 99 4x4 Blazer (8.5/3.42) without the ZR2 option, and has disc brakes. Will this be the right width of about 60inches? When I punch in the VIN it says that the "track width" is 55.1
Does that mean the axle width (from brake plate to brake plate) is that? Or might it still be 59.5 inches wide? Does the 99 Blazer 4x4 have a 60" width?

I don't want to hassle with getting the wrong axle. Like I said, I can find them with the right ring gear and ratio, But I am not convinced that what I order will be the right width.
 

Last edited by EOB; 02-21-2019 at 11:14 AM.
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Old 02-21-2019, 11:08 AM
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Don't know about the width, but it's my understanding that most S10 trucks and blazers came with the 7.6" ring gear (non ZR2.). Where are you finding axles with the 8.5"? I would love to replace my baby ten bolt with the bigger one
 
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Old 02-21-2019, 11:13 AM
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I just keep doing searches and finding on ebay, LKQ, and other places that have 8.5 RG. I think it was after 95 they had them in 4x4s, but the 4x2 are mostly 7.5 or 7.625.
For example: https://www.ebay.com/itm/1998-2003-C...axtL:rk:1:pf:1
 
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Old 02-21-2019, 11:30 AM
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Originally Posted by EOB View Post
Hello. I'm looking for a 59-60 inch rear axle for my 51 chevy car. I believe the S10 4x4 fits this right. But does it matter if it's a Blazer instead of a Truck? I am getting conflicted reports. I want an 8.5 ring gear (not the 7.5) and a 3.42 ratio. Which S10 would work? I'd even prefer the drum brakes for the back.

Can you help me know what year, make and model I would need to search for? Some people say the 95 and newer. Others tell me the early 80s S10 and GMC 215. Others say the axles without the ZR2 can work but what you say here seems like it wouldn't. My biggest issue is making sure the axle is the right width and that is the hardest part to know for certain. I can find axles online that are S10 with 8.5/3.42 but I keep finding conflicting info that makes me wonder if it's really 60 inches.
FOR EXAMPLE: I am looking at a 99 Blazer (8.5/3.42) without the ZR2 option, and has disc brakes. Will this be the right width of about 60inches? When I punch in the VIN it says that the "track width" is 55.1
Does that mean the axle width (from brake plate to brake plate) is that? Or might it still be 59.5 inches wide?

I don't want to hassle with getting the wrong axle. Like I said, I can find them with the right ring gear and ratio, But I am not convinced that what I order will be the right width.
Here you go.

2wd 54.5"
4wd 59"
ZR2 63"

These are wheel mounting to wheel mounting measurements. You can check your existing 2WD to be sure. In any case STD 4WD is 4.5" wider than the 2WD.

If the Blazer is 4WD and not a ZR2 then it should be 59" A non-ZR2 8.5 rear (4WD or 2WD) with 28 spline axles is pretty rare. For a S10/Blazer 8.5 or 8.65 rear make sure the axle tubes get significantly larger, right before going into the center of the housing. In 2000, factory "8.5 S10 rears" went to bigger carrier bearings, 8.65" ring gear, stronger 30 spline axles, different pinion yoke / bigger diameter pinion seal - but you can use 8.5 ring/pinion/yoke/seal in them. If you end up using a non-factory differential on the 8.625 rears, then standard 12-bolt carrier bearings are used. You can easily convert these disk brake rears to drums, but you will need to carefully enlarge the backing plate register hole to exactly fit the disk brake rear register. This is machining that is definitely easier said than done, but a fabricator type person with equipment can do it (I tried to figure out a way at home but ended up with an expert to do it). Just get new 1970's 8.5 backing plates (only ones that are available other than G-body), matching 1970's wheel cylinders, matching 1970's drums, and matching 1970's shoes/hardware. If you end up using a non-factory differential on the 8.625 rears, then standard 12-bolt carrier bearings are used.

I have a 2002 S10 Extreme 2WD 8.65" rear in my drag race 2WD 1989 S10. It is converted to drum brakes so I can use c-clip eliminators for my full spool - so I know about the conversion first hand. Gears, forged pinion yoke, full spool, c-clip eliminators, pinion bearing, pinion seal, and rear cover are all aftermarket 8.5 items. Carrier bearings and carrier shims are for a 12-bolt Chevy rear. Funny that my bearing kit gave me the right carrier bearings, but the wrong carrier shims (for smaller old 8.5 OD size bearings).
 

Last edited by LesMyer; 02-21-2019 at 11:51 AM.
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Old 02-21-2019, 11:45 AM
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Thanks Les. So just to be sure, if I find an axle offered as a 4x4 Blazer (97-03) but says "without ZR2 opt", will that mean it should be the 59inch, and not the 63"? Or will it still be a 63 but without that suspension package?
 
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Old 02-21-2019, 12:30 PM
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Originally Posted by EOB View Post
Thanks Les. So just to be sure, if I find an axle offered as a 4x4 Blazer (97-03) but says "without ZR2 opt", will that mean it should be the 59inch, and not the 63"? Or will it still be a 63 but without that suspension package?
It will be the 59" axle, but the 7.6" ring gear
 
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Old 02-21-2019, 01:12 PM
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Thanks. However, this quote from LKQ shows that the 99 blazer 4x4 has the 8.5 ring gear. Is that correct? And if so, will it fit my 51 chevy that needs a 59-60 axle since this '99 is without the ZR2?

Will this be a 59" width since it is without the ZR2? I am only trying to confirm before I order today. Thanks.
 

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