Clear and to the point 5 to 6 lug axle question

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885speed

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Alright, so I've been searching high and low for all the correct info on my upcoming 5 to 6 lug conversion.
Through all said searching on here, and other spots around the web I've found tons of conflicting information(gee who could've guessed that?[end sarcasm]).

Okay so, I've drawn my conclusion that a 4x4 axle will bolt right up with no issue other than possible rusty u-bolts and likely a different u-joint may be needed which isn't a big deal. I have no intention of trying to search for a 4x2 Sub 6 lug axle because the 2010-ish Z71 wheels I have for the truck should sit in the factory location with a 4x4 axle width wise when comparing backspacing/axle width. Front end will be a no-brainer with lift spindles and 1997 c2500 LD Sub rotors.

But, because this truck is my daily driver and I have a strong desire not to fight or fuss with anything, to those who have already done this swap I would greatly appreciate a word of wisdom.

Only other main concern is wheel center bore fitment, but I'll be test fitting those first to be sure.

If its not a super hot day when I end up doing it, I may take a ton of pictures and make a sticky-worthy thread to properly document and walk through for others wanting to do the same swap.

That being said, please chime in if you have done this axle swap.


Thanks in advance.
 

someotherguy

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Clear and to the point? Not so much..

We have no idea what your vehicle is other than a tiny avatar pic. Please include in post and don't make us guess. :) Though I'll surmise it's a 2WD 1500.

What is a 4x2 6 lug Sub axle? I'm not familiar with any 2WD GMT400 Suburbans that came 6 lug, if that's what you mean. They may exist but have got to be rare. The 6 lug (7200lb gvwr) 2WD 2500's I've seen (and owned) were all pickups, not SUV's.

Are you *sure* you want to use a 4WD rear axle in your 2WD truck? I don't think you're going to be happy with a noticeably wider rear track width than the front, especially with OEM 6 lug 4WD wheels. The look is going to be...well, that's a matter of personal taste. Also, those Z71 wheels are going to give you clearance problems up front due to too much backspacing. Speaking from experience using 4WD wheels on a C2500LD just to roll it around. Suspension interference on the wheel -and- tire is very likely.

You should always use new U-bolts as the old ones are a one-time deal regardless of rust. Sure; plenty of people have gotten away with re-using them if they're not toast, but it's not wise.

Be sure whatever truck you get the 14 bolt from, grab the axle tube saddles too, as they're larger to match the axle tubes. Your existing ones will not fit.

Yes on the conversion u-joint; if you know that then you should probably already have the part #'s from those threads.

While they're not exactly common, the 2WD 6 lug 14 bolt isn't rare either, and you can find the proper 2WD 14 bolt axle if you hunt a little bit. The results will be worth it.

Richard
 

454cid

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Are you *sure* you want to use a 4WD rear axle in your 2WD truck? I don't think you're going to be happy with a noticeably wider rear track width than the front, especially with OEM 6 lug 4WD wheels. The look is going to be...well, that's a matter of personal taste. Also, those Z71 wheels are going to give you clearance problems up front due to too much backspacing. Speaking from experience using 4WD wheels on a C2500LD just to roll it around. Suspension interference on the wheel -and- tire is very likely.

Are the 2wds that narrow up front? Is the track width the same front to back, already? My 4x4 front end is much wider than the rear.

At some point GM made the Z71 available in 2wd... I have no idea if that changes the rims.
 

98chevy2500SS

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The only 2WD truck of this gen to have 6 lugs, to my knowledge, is the 2500LD. I think he might be talking about a GMT800 2WD Burb axle, but I could be wrong.
 

someotherguy

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Are the 2wds that narrow up front? Is the track width the same front to back, already? My 4x4 front end is much wider than the rear.

At some point GM made the Z71 available in 2wd... I have no idea if that changes the rims.
Haven't measured track width differences up front but I can tell you with some GMT800 stockers (17's IIRC?) on the front of an '88 C2500LD, there was considerable interference up front when turning. Too much backspacing. It's been too many years (10 now?) to recall exactly what the issue was; if I recall, the wheel hoop was rubbing on the upper ball joint/control arm area (stamped arms, light duty 2500) and possibly the tires were rubbing on the frame at full lock.

The real issue with remembering the exact combo was I had a parts truck with some aftermarket wheels that a customer wanted; I did a sale/partial trade with him on his GMT800 stock wheels/tires so that I still had something to roll the truck around with. They were either 16's or 17's. Had to be careful how sharp I turned the truck after that - it was OK for low speed yard maneuvers on a parts truck, but definitely not road-worthy.

Richard
 

885speed

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Clear and to the point? Not so much..

Well, I had the intention of keeping it short and direct but that didn't happen. My bad.

We have no idea what your vehicle is other than a tiny avatar pic. Please include in post and don't make us guess. :) Though I'll surmise it's a 2WD 1500.
Yep, my bad again. You're correct though, '97 C1500


What is a 4x2 6 lug Sub axle? I'm not familiar with any 2WD GMT400 Suburbans that came 6 lug, if that's what you mean. They may exist but have got to be rare. The 6 lug (7200lb gvwr) 2WD 2500's I've seen (and owned) were all pickups, not SUV's.
That goes back to my mention of the conflicting information out there that I've found.
Yes, supposedly C2500LD 2wd 7200lb gvwr Suburbans came with a more narrow 6 lug 14 bolt as well as C2500LD trucks. At least from what I've read.


Are you *sure* you want to use a 4WD rear axle in your 2WD truck? I don't think you're going to be happy with a noticeably wider rear track width than the front, especially with OEM 6 lug 4WD wheels. The look is going to be...well, that's a matter of personal taste. Also, those Z71 wheels are going to give you clearance problems up front due to too much backspacing. Speaking from experience using 4WD wheels on a C2500LD just to roll it around. Suspension interference on the wheel -and- tire is very likely.
Yes. Considering my scenario, having a bad axle housing and already having the Z71 wheels with good tires on them ready to go. Not to mention my truck is in need of a new set of tires anyways.

From what I've been able to find, the lift spindles I plan on using to level the truck out also bump the track width out (1.5" IIRC) on each side. Which should bring it to within a half inch of the rear being 4" wider overall. I plan on checking this once the truck is apart and can be compared with the new lift spindle.
Also to my understanding for the front, some NBS wheels may require a small spacer to allow the center cap to fit which would soak up a bit of that difference as well.
With all that being said, I'm not expecting to have clearance issues up front. But if I do I'll have to address it at that time, I could always swap back to the 5 lug rotor and put my 15's back on worst case while I come up with a solution.



Yes on the conversion u-joint; if you know that then you should probably already have the part #'s from those threads.

While they're not exactly common, the 2WD 6 lug 14 bolt isn't rare either, and you can find the proper 2WD 14 bolt axle if you hunt a little bit. The results will be worth it.

I've found threads referencing it, but have yet to see any part numbers for the correct u-joint. Wasn't incredibly concerned about that since this won't be happening for at least a few weeks and I have some time to track down the correct one.

That brings up a good point that I completely neglected to mention, which is that I'm open to finding either a 10 bolt or a 14 bolt as long as it is a G80 axle with matching ratio of course. Strength is not a major requirement, even though I do use It as a truck and not just a DD fairly often, the heaviest thing I generally tow is a golf cart on my 5x8 trailer.


Be sure whatever truck you get the 14 bolt from, grab the axle tube saddles too, as they're larger to match the axle tubes. Your existing ones will not fit
Great info, thank you for that. Not something that has been ever mentioned in posts I've read.
 

someotherguy

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No worries. It's a lot of details and if you post a book to start with then a lot of people tend to skip right over the post, so I understand!

I'm not gonna say that C2500LD Suburban doesn't exist but I've never seen one. If they do exist, I can't imagine why the rear axle would be any narrower than the C2500LD pickup. It's narrower than a K2500LD axle by a couple inches for sure, but that's the same difference you'd see in a C1500 vs. K1500 10 bolt.

If you're gonna run lift spindles and they do end up spacing the hubs out a little then that will probably solve any interference issues up front.

The part # I've seen thrown around for the conversion joint is NAPA 447 but you should triple-check that.

Richard
 
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So minus doing any 14b swap and sticking with the 10b I have a 99 tahoe limited im halfway in middle of converting withe the front done if i found a complete 4wd rear end with exact rpo codes from a tahoe i can drop it and fairly easily bolt back under mine with no major changes? if not what rear end do i need other than a 14b?
 
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