14b 9.5" into K2XX

[fozzi58]

OK so my 100k+ Suburban is just starting to experience her first problems. Had the rear diff serviced and chunks of the spider gears were laying in the bottom. Kind of expected with 400hp at the tire and driving her as if she's GM's flagship 2 seater.

So before I order a bunch of parts to rebuild the the 12 bolt in this thing (which I have been told are not the strongest diffs) I started looking into the 14 bolt 9.5s which is a much more stout rear.

@swathdiver 's chart is a huge help so I can pinpoint what years I can look for. I will probably just rebuild it with new 4.10s and a Truetrac but I may keep the stock internals for a bit.. However, I am still not 100% sure this rear will fit in the K2XX platform. While the GMT900's and K2XX share a lot, I can't find anything definitive to find out if I should be looking for a half-floater or full floater 14 bolt.

I've been watching vids and reading articles on 14b into NBS and GMT900's to replace the ****** 10 bolt, but nothing for a swap into the K2XX platform.

Anyone here have the opportunity to upgrade their K2XX with the Saginaw rear?



Its a 12 bolt 9.5" rear in there now. Not a 14 bolt.

 

[strutaeng]

You are talking about the 8 lug 14 bolt, right? How would you convert the 8 lug to 6 lug?

Maybe the 14b 9.5" semi float can be ordered with 6 lug axles? Like from that company that custom makes them? Dutchman IIRC? Drill rotors to match everything else?

The 14b 10.5" is a full float design and probably much more difficult to swap?

The other difference is the 14 bolt came with leaf springs. But a torch and welding can fix bracketry etc.

BTW, I have a truck 12 bolt 9.5" axle from a 2KXX I want to swap into my 99 Silverado 10 bolt 8.6", but haven't gotten there yet...

 

[MobileHomie]

OK so my 100k+ Suburban is just starting to experience her first problems. Had the rear diff serviced and chunks of the spider gears were laying in the bottom. Kind of expected with 400hp at the tire and driving her as if she's GM's flagship 2 seater.

So before I order a bunch of parts to rebuild the the 12 bolt in this thing (which I have been told are not the strongest diffs) I started looking into the 14 bolt 9.5s which is a much more stout rear.

@swathdiver 's chart is a huge help so I can pinpoint what years I can look for. I will probably just rebuild it with new 4.10s and a Truetrac but I may keep the stock internals for a bit.. However, I am still not 100% sure this rear will fit in the K2XX platform. While the GMT900's and K2XX share a lot, I can't find anything definitive to find out if I should be looking for a half-floater or full floater 14 bolt.

I've been watching vids and reading articles on 14b into NBS and GMT900's to replace the ****** 10 bolt, but nothing for a swap into the K2XX platform.

Anyone here have the opportunity to upgrade their K2XX with the Saginaw rear?



Its a 12 bolt 9.5" rear in there now. Not a 14 bolt.

It went 100K miles. Rebuild the 12 bolt with quality aftermarket parts.
Flog it for another 100K...Profit?

 

[swathdiver]

OK so my 100k+ Suburban is just starting to experience her first problems. Had the rear diff serviced and chunks of the spider gears were laying in the bottom. Kind of expected with 400hp at the tire and driving her as if she's GM's flagship 2 seater.

So before I order a bunch of parts to rebuild the the 12 bolt in this thing (which I have been told are not the strongest diffs) I started looking into the 14 bolt 9.5s which is a much more stout rear.

@swathdiver 's chart is a huge help so I can pinpoint what years I can look for. I will probably just rebuild it with new 4.10s and a Truetrac but I may keep the stock internals for a bit.. However, I am still not 100% sure this rear will fit in the K2XX platform. While the GMT900's and K2XX share a lot, I can't find anything definitive to find out if I should be looking for a half-floater or full floater 14 bolt.

I've been watching vids and reading articles on 14b into NBS and GMT900's to replace the ****** 10 bolt, but nothing for a swap into the K2XX platform.

Anyone here have the opportunity to upgrade their K2XX with the Saginaw rear?



Its a 12 bolt 9.5" rear in there now. Not a 14 bolt.

Right, you have a Salisbury 12-bolt which is supposedly stronger than the older 14-bolt. I do not know if they will drop right in.

If I had your truck, I would drop in the Salisbury 12-bolt 9.76" gear, the one used behind the 6.2s. I think you already have 1415 u-joints too.

 

[swathdiver]

You are talking about the 8 lug 14 bolt, right? How would you convert the 8 lug to 6 lug?

Maybe the 14b 9.5" semi float can be ordered with 6 lug axles? Like from that company that custom makes them? Dutchman IIRC? Drill rotors to match everything else?

The 14b 10.5" is a full float design and probably much more difficult to swap?

The other difference is the 14 bolt came with leaf springs. But a torch and welding can fix bracketry etc.

BTW, I have a truck 12 bolt 9.5" axle from a 2KXX I want to swap into my 99 Silverado 10 bolt 8.6", but haven't gotten there yet...

GM made the 14-bolt semi-floaters with 6 lug axles in the GMT900s.

 

[strutaeng]

GM made the 14-bolt semi-floaters with 6 lug axles in the GMT900s.

Yes, but I was under the impression that bearings or something was different on those. Like, they are kinda like a hybrid between the old 14 bolt and the 10 bolt. I remember reading about this somewhere.

I thought OP was asking about the 8 lug 14 bolt. Maybe not?

Edit: didn't see your previous reply until now...

 

[fozzi58]

@swathdiver has a list (here: GMT900 Differentials) that lists the 6 Lug 14 bolt 9.5" rears. They are a stout rear. I am searching the web to find out if that rear, lets say out of a 2010 avalanche, will fit into my burb. I remember seeing an Escalade with an Armageddon twin turbo kit and I vaguely remember he mentioned he replaced the rear with the Saginaw. I'm looking for his vid so I can get a contact and reach out to him.

Right, you have a Salisbury 12-bolt which is supposedly stronger than the older 14-bolt. I do not know if they will drop right in.


If I had your truck, I would drop in the Salisbury 12-bolt 9.76" gear, the one used behind the 6.2s. I think you already have 1415 u-joints too.

Is the 6.2 rear different from the 5.3 rear? Obviously the ring gear is different (9.5 vs 9.76) but what about the housing? The Saginaws are pretty cheap considering - there are a handful for $250 on LQK (plus shipping) but if its stronger than the 12 bolt, its a better starting point? I knew the G80 was going to eventually grenade with the added power but a lot of the readings tell me to swap to the 14 bolt.

If the 12 bolt casing is good enough, then adding a TrueTrac, a set of gears (thinking 3.73 or 4.10), and some yukon or strange axels, it should be able to handle about 800HP. My long term goal is to get 650 to the tire with a pulley swap (14-16lbs pulley for the Whipple) but for daily and autocross I would probably run a 10lbs-12lbs cause I don't need that power on the street.

What are your thoughts on trying to make the Saginaw work vs building the Salisbury?

*** EDIT: My U-Joints and drive shaft were upgraded when I had the Whipple installed. Its a custom aluminum 1 peice 5.5" diameter driveshaft good to 1000 lbs/ft torque and the u-joints to accompany that power. I went overkill on purpose

 

[fozzi58]

Spent the weekend hunting down information but to know avail. Nothing definitive.

Option 1 - build up the current 12 bolt
K2XX Differential part numbers and descriptions
Part# 23199120 - Suburban, Yukon XL. With limited slip. Escalade ESV. Tahoe. Yukon. 5.3l
Part# 23199119 - Suburban, Yukon XL. Without limited slip. Escalade. Yukon. 6.2l. Tahoe. All. 6.2l.

There is nothing out there that definitively states the Diff housings are different. Only the part nums are diff. I know my truck has the 9.5 but if the guts of a 9.76 fit inside the 9.5 housing, I may be better off getting those parts.

Yukon Gear:
yga24653 - gears
yga14217 - overhaul kit (includes gasket?)
yga21815 - axels - do you have wheel studs?
yga33081 - c clips

Eaton TrueTrac Carrier

My shop said they can weld the tubes and maybe add a couple gusset brackets to strengthen the unit

Option 2 - Roll the dice with a 14 bolt.
The 14 bolt differential came in some SUVs and mostly P/U's. (GMT900 platform)
It is a beefier rear plus it has a 10.5" ring gear
No guarantee it will fit but should since the GMT900 and K2XX platform share quite a bit (E.G. up\low trailing arms\panhard bar for GMT900 fit K2XX; Rear shocks, brakes, etc).
No info I can find that states mounting brackets are the same.
I have read that there's a half floater and full floater version. (Forgive my ignorance on rear diffs, but no idea what that means)

The 14 bolt seems to be a better platform to build off but not 100% sure which way to go.

If anyone has any suggestions or insight, it would be appreciated. I need to make a decision rather quickly since Its sitting at the shop with a broken rear end at the moment. Thanks in advance