What axles?
- Thread starter Maaso
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supersports10
New member
Re: What axles?
rear's the same, front is an open dif, with a different right side axle.
Maaso said:
rear's the same, front is an open dif, with a different right side axle.
Re: What axles?
Rears good, the rear right hand side is what got ****ed up.
Now, I remember reading somewhere that there were like....3 different rear ends GM used under the S-trucks, 7.5, 7.75, and an 8.5 if I remember (Im more than likely wrong, it was years ago when I was in highschool) but will all the axles interchange between the different housings?
supersports10 said:rear's the same, front is an open dif, with a different right side axle.
Rears good, the rear right hand side is what got ****ed up.
Now, I remember reading somewhere that there were like....3 different rear ends GM used under the S-trucks, 7.5, 7.75, and an 8.5 if I remember (Im more than likely wrong, it was years ago when I was in highschool) but will all the axles interchange between the different housings?
supersports10
New member
Re: What axles?
yes... depending on budget i would def go with a 8.5 out of a 95 and newer 4x4 4.3 5 speed s10 NON ZR2!!
this is the best axle out there,
Maaso said:
yes... depending on budget i would def go with a 8.5 out of a 95 and newer 4x4 4.3 5 speed s10 NON ZR2!!
this is the best axle out there,
'JustDreamin'
Dream: 6LV8 Turbo Bravada
Re: What axles?
Let's try to clear up some confusion....
There are 2 different rear housings available.
Most common (and sadly the weakest) is the 7.5" 10 bolt. 7.5" (also called the 7.625") is the ring gear diameter. Its in most all S10s, all 4th Gen camaros, 78-88 A and G bodies, Astro's, and a few other applications that really should have a better rear.
The other available rear is the 8.5" 10-bolt. This is a completely different housing, parts don't interchange with the 7.5" 10-bolt. This rear is found in 1995 and newer trucks with the 4.3 V6 AND manual trans (auto's got the 7.5").
There are 3 different widths used under S series trucks.
2wd (the narrowest)
4wd (about 4" wider)
ZR2 4wd (about 4" wider still, or about 8" wider than the 2wd).
Sy's and Ty's used a 4wd width, 7.5" 10-bolt. That's what you need parts for. Your other alternative is to replace the entire rear with something else (8.5" 10-bolt, Ford 9", GM 12-bolt, whatever).
And the front axle on all S10 platform trucks is an open diff. There is no limited slip offered for the front axle (factory never put them in and no aftermarket). There used to be a "locker" insert, but I've heard its been discontinued. I have no confirmation of that.
'JustDreamin'
Let's try to clear up some confusion....
There are 2 different rear housings available.
Most common (and sadly the weakest) is the 7.5" 10 bolt. 7.5" (also called the 7.625") is the ring gear diameter. Its in most all S10s, all 4th Gen camaros, 78-88 A and G bodies, Astro's, and a few other applications that really should have a better rear.
The other available rear is the 8.5" 10-bolt. This is a completely different housing, parts don't interchange with the 7.5" 10-bolt. This rear is found in 1995 and newer trucks with the 4.3 V6 AND manual trans (auto's got the 7.5").
There are 3 different widths used under S series trucks.
2wd (the narrowest)
4wd (about 4" wider)
ZR2 4wd (about 4" wider still, or about 8" wider than the 2wd).
Sy's and Ty's used a 4wd width, 7.5" 10-bolt. That's what you need parts for. Your other alternative is to replace the entire rear with something else (8.5" 10-bolt, Ford 9", GM 12-bolt, whatever).
And the front axle on all S10 platform trucks is an open diff. There is no limited slip offered for the front axle (factory never put them in and no aftermarket). There used to be a "locker" insert, but I've heard its been discontinued. I have no confirmation of that.
'JustDreamin'
Rinkrat456
Got LS1?
Re: What axles?
Very close, JustDreamin. Early S-trucks came with the 7.5" ring geared rear end which had 26 spline axle shafts and a weak housing. Around 1990 GM started putting the beefier 7.625" rear into more and more trucks, finally making it standard equipment in '93 with a little stronger 28 spline axle shafts. From the outside appearance, the two axles look identical, though inside the parts do not interchange.
There is a common misconception in the S-truck community that ALL high output 4.3L 5-speeds came with the 8.5" rear. I don't know how many exactly, but I know it's not all. Being obsessed with S-trucks, whenever one comes into work for new tires I scope out all the parts and options and rarely see an 8.5" rear. It's so rare some call it a myth that GM ever put the 8.5"/30 spline rear into 2wd/non-ZR2 trucks, but I've seen them a few times especially with the 4.3/5-speed Xtreme's and ZQ8's, but even then not ALL, I've found.
Really what it comes down to is just going junkyard hopping and finding your own. You can tell an 8.5" rear by the circular differential housing/cover compared to the 7.5/7.625" oval cover/housing. Also, the 8.5" will have axle tubes that step up in diameter as they reach the housing. The increase in tube diameter happens right at the sway bar mount, so many guys miss the slight taper that's a dead give-away.
The 8.5" rear came in 2wd's, 4wd's and ZR2's. Finding one in anything but a ZR2 is sheer luck. 2wd's are 54" from WMS to WMS. 4wd's are 59" from WMS to WMS. ZR2's are even wider, measuring in around 63" depending on disc brakes or drums. Sy/Ty's have the 7.625" 4wd rear, so 59" wide with drum brakes. The reason the AWD terrors of the road got the 4wd stance, is because having more backspacing on the rims places the center of the wheel and tire more over the ball joints, thus saving them from hard driving longer. Look at any sports car, you'll see the same thing. On a side note, Bravada's have the 4wd rear, also 59" wide. As Safari and Astro vans use the 7.625", the mounting pad is different along with stud size, so stock S-truck wheels will not bolt up to an Astro/Safari rear in stock form. Some Astro vans even come with the full size 6x5.5" bolt pattern, just FYI if you're looking for compatible rears.
My best advice if you're looking for a 3.42 capable rear, use car-part .com to hunt down the nearest 4wd 8.5" rear, non-ZR2. They will be hard to find, you'll probably have to drive very far to get it, and expect to pay no less than $400 for a junkyard rear. Even then it might be worth it, considering the 8.875" 12 bolts from Currie cost two-to-three times the junkyard 8.5", but deals can be found, for sure.
Very close, JustDreamin. Early S-trucks came with the 7.5" ring geared rear end which had 26 spline axle shafts and a weak housing. Around 1990 GM started putting the beefier 7.625" rear into more and more trucks, finally making it standard equipment in '93 with a little stronger 28 spline axle shafts. From the outside appearance, the two axles look identical, though inside the parts do not interchange.
There is a common misconception in the S-truck community that ALL high output 4.3L 5-speeds came with the 8.5" rear. I don't know how many exactly, but I know it's not all. Being obsessed with S-trucks, whenever one comes into work for new tires I scope out all the parts and options and rarely see an 8.5" rear. It's so rare some call it a myth that GM ever put the 8.5"/30 spline rear into 2wd/non-ZR2 trucks, but I've seen them a few times especially with the 4.3/5-speed Xtreme's and ZQ8's, but even then not ALL, I've found.
Really what it comes down to is just going junkyard hopping and finding your own. You can tell an 8.5" rear by the circular differential housing/cover compared to the 7.5/7.625" oval cover/housing. Also, the 8.5" will have axle tubes that step up in diameter as they reach the housing. The increase in tube diameter happens right at the sway bar mount, so many guys miss the slight taper that's a dead give-away.
The 8.5" rear came in 2wd's, 4wd's and ZR2's. Finding one in anything but a ZR2 is sheer luck. 2wd's are 54" from WMS to WMS. 4wd's are 59" from WMS to WMS. ZR2's are even wider, measuring in around 63" depending on disc brakes or drums. Sy/Ty's have the 7.625" 4wd rear, so 59" wide with drum brakes. The reason the AWD terrors of the road got the 4wd stance, is because having more backspacing on the rims places the center of the wheel and tire more over the ball joints, thus saving them from hard driving longer. Look at any sports car, you'll see the same thing. On a side note, Bravada's have the 4wd rear, also 59" wide. As Safari and Astro vans use the 7.625", the mounting pad is different along with stud size, so stock S-truck wheels will not bolt up to an Astro/Safari rear in stock form. Some Astro vans even come with the full size 6x5.5" bolt pattern, just FYI if you're looking for compatible rears.
My best advice if you're looking for a 3.42 capable rear, use car-part .com to hunt down the nearest 4wd 8.5" rear, non-ZR2. They will be hard to find, you'll probably have to drive very far to get it, and expect to pay no less than $400 for a junkyard rear. Even then it might be worth it, considering the 8.875" 12 bolts from Currie cost two-to-three times the junkyard 8.5", but deals can be found, for sure.
'JustDreamin'
Dream: 6LV8 Turbo Bravada
Re: What axles?
You're right about a bunch of things...
The difference between the 7.5" and the 7.625" is the axle spline count....26 vs 28....I don't know if the housings are any stronger.....The A & G bodies have the 26 spline axle, the 4th gen Camaro's have the 28 spline.
I've got one of the POS's in my '93 Z28. Put the 3rd set of gears in it a week ago. Yes, it has 148k on it, yes its a manual trans, and yes, I'm kinda hard on it. But the last set of gears gave up without any drama (just started whining). At least the previous set went BANG. Took 2 teeth off the pinion in both cases. Why did GM put that thing in there? Should have got the 8.5" 10-bolt in the first place.
I know the 8.5" 2wd axle exists, because one of my ex-coworkers had one in his S10 pickup, which I think was a 2001.
If you ever search Car-Part.com, seems like every yard around has an 8.5" rear. But you call them, make them verify (with pictures) and miraculously, it turns back into a 7.5". Funny, but not really.
Another way to tell the 7.5" & 8.5" apart is the "lugs" on the bottom of the case (centersection). The 7.5" has 2 lugs that are "teeth" shaped, (triangular). Makes me think of Dracula, I want to suck all the $$$ out of your wallet. The 8.5" has 2 lugs that are mostly rectangular (with the long side parallel to the ground). I've seen some pictures around that do a much better job of identifying the difference, but I'm lazy right at the moment.
The 4wd's use the high positive offset wheels for a reason. It's to reduce scrub radius to zero (or close to it). I believe the reason that zero scrub radius is desirable is to help minimize torque steer. I'm not 100% on that being the reason, however.....
Just to be warned, a 8.5" S10 junkyard rear is still a good way to spend a bunch of money. The 8.5" was still available either as an open diff or a limited slip. The open diff isn't very desirable from a performance aspect, so expect to spend $$$ fixing that.
And the limited slip that GM uses in the truck platforms is a POS. To be specific, its an Eaton Gov-Loc. Its something that bugged the heck out of me when I had it in my Suburban (got rid of the truck).
Here's how it (doesn't) works: It's activated by a difference in relative speed between the two axle shafts (difference has to be 100rpm or more). At that point, it activates the clutch packs to lock the rear up, and hopefully stop the spinning. It also has a centrifugal element, so that it stops engaging above 25mph. If you engage it below 25 mph, it'll stay engaged until you lift off the throttle, but won't re-engage until you're below 25mph and have wheelspin (enough for that 100rpm difference). They're also notorious for being grenades (cases are weak).
So, you're really spending a fair chunk of money on a rear that doesn't have a decent limited slip available, and if you've got to change that, you're going to need to put at least bearings and probably gears in it as well. Basically, you'll spend a fair bit more than the $400 it'll cost you at the yard, and that doesn't include upgrading axle shafts (to aftermarket ones, which probably isn't necessary) or upgrading to C-Clip eliminators (which if you're running drum brakes is just short of mandatory, disk brakes will typically act as axle retainers in the event of a break, but that does depend upon the disk brake setup).
'JustDreamin'
You're right about a bunch of things...
The difference between the 7.5" and the 7.625" is the axle spline count....26 vs 28....I don't know if the housings are any stronger.....The A & G bodies have the 26 spline axle, the 4th gen Camaro's have the 28 spline.
I've got one of the POS's in my '93 Z28. Put the 3rd set of gears in it a week ago. Yes, it has 148k on it, yes its a manual trans, and yes, I'm kinda hard on it. But the last set of gears gave up without any drama (just started whining). At least the previous set went BANG. Took 2 teeth off the pinion in both cases. Why did GM put that thing in there? Should have got the 8.5" 10-bolt in the first place.
I know the 8.5" 2wd axle exists, because one of my ex-coworkers had one in his S10 pickup, which I think was a 2001.
If you ever search Car-Part.com, seems like every yard around has an 8.5" rear. But you call them, make them verify (with pictures) and miraculously, it turns back into a 7.5". Funny, but not really.
Another way to tell the 7.5" & 8.5" apart is the "lugs" on the bottom of the case (centersection). The 7.5" has 2 lugs that are "teeth" shaped, (triangular). Makes me think of Dracula, I want to suck all the $$$ out of your wallet. The 8.5" has 2 lugs that are mostly rectangular (with the long side parallel to the ground). I've seen some pictures around that do a much better job of identifying the difference, but I'm lazy right at the moment.
The 4wd's use the high positive offset wheels for a reason. It's to reduce scrub radius to zero (or close to it). I believe the reason that zero scrub radius is desirable is to help minimize torque steer. I'm not 100% on that being the reason, however.....
Just to be warned, a 8.5" S10 junkyard rear is still a good way to spend a bunch of money. The 8.5" was still available either as an open diff or a limited slip. The open diff isn't very desirable from a performance aspect, so expect to spend $$$ fixing that.
And the limited slip that GM uses in the truck platforms is a POS. To be specific, its an Eaton Gov-Loc. Its something that bugged the heck out of me when I had it in my Suburban (got rid of the truck).
Here's how it (doesn't) works: It's activated by a difference in relative speed between the two axle shafts (difference has to be 100rpm or more). At that point, it activates the clutch packs to lock the rear up, and hopefully stop the spinning. It also has a centrifugal element, so that it stops engaging above 25mph. If you engage it below 25 mph, it'll stay engaged until you lift off the throttle, but won't re-engage until you're below 25mph and have wheelspin (enough for that 100rpm difference). They're also notorious for being grenades (cases are weak).
So, you're really spending a fair chunk of money on a rear that doesn't have a decent limited slip available, and if you've got to change that, you're going to need to put at least bearings and probably gears in it as well. Basically, you'll spend a fair bit more than the $400 it'll cost you at the yard, and that doesn't include upgrading axle shafts (to aftermarket ones, which probably isn't necessary) or upgrading to C-Clip eliminators (which if you're running drum brakes is just short of mandatory, disk brakes will typically act as axle retainers in the event of a break, but that does depend upon the disk brake setup).
'JustDreamin'
JSM
Active member
Re: What axles?
If you plan to spend any money teh 8.5" is the way to go. Just dreamin is right on with what he said.
someone mentioned ford 9". I have yet to find a 3.42 or 3.08 gear available for them, so unless you go 2wd or odd tire size not a good option. I wish it was as it would make things easier for me for other reasons.
I plan to buy a 8.5" from a full size and just cut it down, but I am making more power than most and a little overkill. Be aftermarket axles, posi, etc.
If you plan to spend any money teh 8.5" is the way to go. Just dreamin is right on with what he said.
someone mentioned ford 9". I have yet to find a 3.42 or 3.08 gear available for them, so unless you go 2wd or odd tire size not a good option. I wish it was as it would make things easier for me for other reasons.
I plan to buy a 8.5" from a full size and just cut it down, but I am making more power than most and a little overkill. Be aftermarket axles, posi, etc.
'JustDreamin'
Dream: 6LV8 Turbo Bravada
Re: What axles?
Closest 9" gearset to 3.42 is 3.50 (which could be made to work with a slightly taller rear tire)
The Ford 8.8" also has a 3.08" available. But again, no 3.42 ratio, closest is either 3.31 or 3.55.
Edit, just looked....GM 1/2 tons typically run either 5 on 5" or 6 on 5 1/2" depending upon year and whether its got 5 or 6 lugs.
'JustDreamin'
Precision Gear has a 3.08 set for Ford 9".JS Manufacturing said:
Closest 9" gearset to 3.42 is 3.50 (which could be made to work with a slightly taller rear tire)
The Ford 8.8" also has a 3.08" available. But again, no 3.42 ratio, closest is either 3.31 or 3.55.
Does anybody know what the width of the full size 8.5" (say '86 1500?) is? Does it change for 2wd vs 4wd? I always meant to measure the one under my Suburban, but now its gone....Maybe a 2wd one would be the correct width or at least fairly close. Still would have the wrong bolt patternJS Manufacturing said:
Edit, just looked....GM 1/2 tons typically run either 5 on 5" or 6 on 5 1/2" depending upon year and whether its got 5 or 6 lugs.
'JustDreamin'
Last edited:
'JustDreamin'
Dream: 6LV8 Turbo Bravada
Re: What axles?
Depends...
If you're just pulling an axle shaft, then yes.
If you're pulling an entire axle, then you need to make sure that it's got the right gear ratio (3.42) or else your transfer case won't like you.
'JustDreamin'
Depends...
If you're just pulling an axle shaft, then yes.
If you're pulling an entire axle, then you need to make sure that it's got the right gear ratio (3.42) or else your transfer case won't like you.
'JustDreamin'
Rinkrat456
Got LS1?
Re: What axles?
That's a pretty good price. I'm surprised the junkyard let you strip the axle shaft from that rear. Usually yards around here don't let anyone open the differential cover because they (the yard) can sell the entire rear axle assembly for $200-400 "as-is" with a clear conscience. Once they open the differential cover, there's a possibility something is wrong with the differential and then the price has to drop, because they know something's broken/wrong.
On a side note, if anyone needs a 4x4 rear with drums, I pulled the 7.625" from the truck this past weekend and swapped in the Ford 8.8. It has 3.08's and G80 Eaton-gov lock. Just pay shipping and it's yours, otherwise it'll collect dust in the shop. Or... tell me what gear ratio you want and anything else I'll do it for a fair price.
That's a pretty good price. I'm surprised the junkyard let you strip the axle shaft from that rear. Usually yards around here don't let anyone open the differential cover because they (the yard) can sell the entire rear axle assembly for $200-400 "as-is" with a clear conscience. Once they open the differential cover, there's a possibility something is wrong with the differential and then the price has to drop, because they know something's broken/wrong.
On a side note, if anyone needs a 4x4 rear with drums, I pulled the 7.625" from the truck this past weekend and swapped in the Ford 8.8. It has 3.08's and G80 Eaton-gov lock. Just pay shipping and it's yours, otherwise it'll collect dust in the shop. Or... tell me what gear ratio you want and anything else I'll do it for a fair price.
Re: What axles?
Well, I said told them I needed an "axle shaft for the ass end of a 93ish 4x4 S-10"
He told me he had one for $35, I get there and its sitting out on the counter waiting for me....its a front CV shaft. I raise a bitch about how I drive an hour and 20 minutes to get there. So they took care of me, they were assholes about it, but they took care of me.
They even gave me some towels to wrap it up in so I didnt get the truck of my moms Lexus all dirty.
Well, I said told them I needed an "axle shaft for the ass end of a 93ish 4x4 S-10"
He told me he had one for $35, I get there and its sitting out on the counter waiting for me....its a front CV shaft. I raise a bitch about how I drive an hour and 20 minutes to get there. So they took care of me, they were assholes about it, but they took care of me.
They even gave me some towels to wrap it up in so I didnt get the truck of my moms Lexus all dirty.
Rinkrat456
Got LS1?
Re: What axles?
The 7.5" rears had 26 spline. 7.625" rears have 28 splined axles, a tad larger ring gear (obviously) and 1/16th inch thicker axle tubes.Maaso said: