Rear Axle ID

[Big T]

So I was pulling spindles/knuckles off of a 2003 GMC Safari 3500 Van that went into inventory 2/17/16. I could not find a glove box on this van for the RPO codes. It had a 14 bolt full floater rear axle. The passenger side caliper and bracket were already gone, driver's side was pushed up against a steel wall and they could not get the wheel off. Could if you dropped the axle. Very clean, but I can't tell if it's positraction and whether it had the 10.5" or 11.5" ring gear. They had drained it of oil and only put back 3 bolts at the bottom.

I took some pictures, including the bar code label on the axle, in hope that someone here could tell me some more details on this axle.

 

[THEFERMANATOR]

Looks likean 11.5" rear axle. The 10.5" axle normally has the fill plug in the cast portion on the front portion of the diff. A 10.5" axle will have the removeable pinion dupport where an 11.5" is a solid casting for the whole diff.

 

[Big T]

Looks likean 11.5" rear axle. The 10.5" axle normally has the fill plug in the cast portion on the front portion of the diff. A 10.5" axle will have the removeable pinion dupport where an 11.5" is a solid casting for the whole diff.

ThankS. I'm told we need the 10.5" for our K2500 Suburbans.

 

[Big T]

ThankS. I'm told we need the 10.5" for our K2500 Suburbans.

Now I'm told that this is simply the HD version of the G80 which came with the Duramax and 1 ton vehicles. It would work with some mods on our K2500 Suburbans. All G80s are locking differentials. Damn, we need to go back and get this. I will try to convince my son to go next weekend.

If my son balks on this, I have the front differential from the '95 wreck, which was a 4.10 ratio truck. I could swap in the other differential and convert mine to a 4.10 ratio. I do pull a 27' boat on an aluminum trailer, which I estimate at 8,500 lbs fully loaded.

 

[THEFERMANATOR]

The 10.5" is a better fit. The 11.5" rear axle is a good bit bigger than the 10.5" axle. Also be aware the 11.5" axle uses either 1410 or 1480 U-joints, not the 1350's your BURB uses now, so you'll have to plan on some driveshaft mods to run it as well.

 

[Big T]

The 10.5" is a better fit. The 11.5" rear axle is a good bit bigger than the 10.5" axle. Also be aware the 11.5" axle uses either 1410 or 1480 U-joints, not the 1350's your BURB uses now, so you'll have to plan on some driveshaft mods to run it as well.

That was my next question, can the yoke on the 10.5" be used on the 11.5" to work with the existing drive shaft?

 

[THEFERMANATOR]

Don't think so. The 11.5" axle is a good bit bigger in pretty much every way from a 10.5". Not sure if they make a 1350 to 1410 bastard joint. And I think your driveshaft would need to shortened anyways. Yokes for the 11.5" axle are also $$$ since they have a rubber mounted balancer/dampener built into them.

 

[Big T]

Don't think so. The 11.5" axle is a good bit bigger in pretty much every way from a 10.5". Not sure if they make a 1350 to 1410 bastard joint. And I think your driveshaft would need to shortened anyways. Yokes for the 11.5" axle are also $$$ since they have a rubber mounted balancer/dampener built into them.

Thanks, based on your input, we'll pass on this. Seems like too many mods and difficult ones at that to make this work. The temptation was the excellent condition of the axle.

I've got enough projects with two sets of knuckles to do the GMT 800 Brake Conversion for both my son's and my Suburban K2500s. Need to order the remaining parts, which we'll spread out over the next 2 months, as it gets pricey.