Help 30 spline conversion on 28 spline rear axle

[83sbc]

Dose any one know what axles I can get that will be 30 spline and fit a stock 83 gmc rear end I believe my stock axles are like 30.75 inches long and bolt pattern is a 5x5 some one plz help urgent

 

[HotRodPC]

@Honky Kong jr is likely to be the best guru on this subject..

However, my .02 is going to be, I'm fairly certain the axle lengths are the same then you'd get just the 30 spline spider gears or carrier if you so choose to go with a locker or limited slip. Are you just wanted the extra 2 splines for strength?

 

[83sbc]

No I bought a 30 spline Limited slipand the guy won’t return my money so I’m looking for axles that I can get in the 30 spline so I can replace my 28 but I need them to fit

 

[HotRodPC]

OK, makes sense. So I'm fairly certain it's 88 and later that are 30 spline. Try a Burb, 2wd Jimmy or C5 Blazer. @Honky Kong jr would know and might even have a spare set.

What limited slip did you get?

 

[HotRodPC]

****, come to think about it, I might have a set. Let me check. They came from an 87 Burb that had an aftermarket Detroit Locker in it. Some 87 Burbs have been know to be 30 spline. Call it a transition year if you will, but by 88 they all were. Now that I remember some 87 Burbs had them, that makes me even more certain 88 up have 30 spline. Lemme see if I can find an Old craigslist ad I had running cuz I had the spline count in that ad. It's been so long now, I just don't recall.

 

[HotRodPC]

Sorry, No go. I had to go all the way back to May 2017 to find the ad, they're 28 spline.

 

[83sbc]

Dam it’s a Eaton I believe I can post pictures of it tomorrow morning so y’all can see but what should I look for as a donor

 

[HotRodPC]

88 up to 91 Squarebody, which leaves you limited to 2wd Burbs, Jimmy and Blazers unless someone can confirm that later model trucks have the same length axles. Are you opposed to buying new axles instead of sourcing used?

 

[83sbc]

No I’m not but I can’t seem to find any rather mine is a 28 spline 30x3/4 long and 5x5 bolt patter but I can’t find he same thing in a 30 spline for some reason and preferred on summit racing bec I can drive up there tomorrow morning to pick up and anywhere else I’ll have to wait for shipping and unfortunately I don’t have that luxury bec the mechanic is not willing to wait any longer

 

[HotRodPC]

$61 each at RockAuto.com + shipping for an 88 R10 Suburban. I think GMSB members still get a 5% discount.

https://www.rockauto.com/en/moreinfo.php?pk=5643834&cc=1301049&jsn=487

 

[HotRodPC]

Your truck is a 83 C1500 right? We can look at RockAuto.com and get your replacements measurements, then compare them to the Burb length. It'll matter at which point to which point you measure. Those are RockAuto.com are 31.38 which is just over 31 1/3 inch. So if you're 30 3/4 they're to long, but to where are you measuring and where do they measure to? Point is, they might be the same length both measurements are taken at the same places.

 

[HotRodPC]

See, for your truck, the same Dana brand claims your axles to be 31.31 inches in length. In the Dana brand for the 88 R10 Burb, they claim to be 31.38 in length. You're talking .07 difference in length. Not even the width of a C clip. I'd just about be willing to bet those 88 R10 Burb axles would fit your rear end and be 30 splines.

 

[HotRodPC]

I mean, let's let others chime in and give their opinions too. I'd hate to see you order on just my hunch and then be wrong.

 

[HotRodPC]

According to Yukon axles, measurement differences are 3/16 of an inch different. So over 1/8th but less than 1/4in.

 

[Honky Kong jr]

You will need different carrier bearings. The carrier you have is probably an 8.6 carrier for an 88 up pick up. Not a big deal. You can use 12 bolt 5 lug axles. You will have to file the inner most part of thecaxle to get proper axle to cross pin clearance once the C- clip is installed. Use a feeler gauge to measure this. I have the part numbers some where for the bearings and races. I have an Eaton 8.6 posi in my front 10 bolt.