Any chance an 88 10 bolt would be 30 spline?

[JeffsJeep04]

Long time lurker, finally got a K5 as a DD. Considering the trade, I have ~$400 into a nearly rust free (for WI, 2 minor rot spots, everything else was just surface. Rockers are solid!) 88 K5 with 17k on the rebuilt 350 (with receipts) and 8k on the HD rebuilt 700R4 (with receipts). Miss having the proper number of pedals on the floor, but I'll just have to deal with the auto for now, feels solid anyway. On to my question...

The spec section of the site shows the 30 spline switch happening in 89, but I've seen some things here and there about possibly rear axles being sooner? Anyone know when the switch happened? I'd like to know without having to pull a shaft, eventually a lockright might find its way into the rear of my K5 and I'd like to only have to pull it once if possible...if it's a transition vehicle, that's probably unlikely though

 

[shovelbill80]

i can't help you, but i've read somewhere that you could get either(luck o the draw?)in 1989. don't know if it's true or not though. that would lead me to believe an '88 is 28 spline. just my opinion too.

 

[4X4HIGH]

1989 was the first year for 30 spline axles in a 10 bolt. Crazier things have happened though AND you never know what a PO might have changed so it would be best to pull an axle and count to be 100% sure.

 

[Fordum]

OK, its almost 2 in the morning, so don't make too much of this, but before you pull an axle, ask around about hub markings.

A long time ago, I remember that there was a way to tell something about an axle, I think the splines, by the shape of the center of the hub.

I have been up over 24 hours, so I'm only hitting on about 9 cylinders. It might not even be that size rear end.

But there is something about the center of the hub on some axles that tells you something about that axle.

Hows that for precise???

 

[JeffsJeep04]

I know ford 9" axles are that way, maybe that's what you were thinking of? It also could be INCREDIBLY likely that since neither ford or GM probably manufacture their own axle shafts that the forge doing them has a way of differentiating between with the "stamp" on the end...save the factory guys a LOT of headache when it comes to sorting between similar but different shafts....can a 30 spline guy post up a shot of his axle flange so us older guys can compare (and post up a shot)? Could be a good reference for the future!

28 spline wouldn't really bother me at all, with the neck down, I can't imagine it is that big of a strength difference, and once I get hard enough to start blowing 10 bolt shafts, I've got a full float 14 bolt sitting in the shed left over from a jeep project

 

[6.2Blazer]

You can give the VIN to the parts department and then have them pull up the replacements parts for the rear axle shafts.

Regarding the neckdown, rear shafts don't have a neckdown like the front shafts.

 

[4X4HIGH]

There is still no better way to tell what he has until he pulls a shaft. ANYONE in the past could have either swapped complete axle assemblies or even went from 28 to 30 spline or vice versa. If I was buying parts I would want to make 200% sure of what I needed BEFORE ordering anything.

 

[tRustyK5]

Definitely pull an axle before ordering a locker. At least get the cover off and give it a visual. Majority of these trucks got a Gov lock, which means a lunchbox locker isn't gonna work unless you swap to an open carrier first.

FWIW my "stock" '90 had a 12 bolt under the rear when I finally got around to looking.

Rene

 

[JeffsJeep04]

Definitely pull an axle before ordering a locker. At least get the cover off and give it a visual. Majority of these trucks got a Gov lock, which means a lunchbox locker isn't gonna work unless you swap to an open carrier first.

FWIW my "stock" '90 had a 12 bolt under the rear when I finally got around to looking.

Rene

No G80 on the RPO sheet, but like you said, who knows what's been swapped in the last 22 years

 

[tRustyK5]

Yup, 10 bolts grenade with stock tires often enough that almost any year replacement could be under there. My RPO showed no G80 either, yet the 12 bolt had one. Actually it was an 11 bolt, one cover bolt was sheared off and MIA.

Rene