Lame 12 bolt swap etc

[burber1989]

Apologies for misspellings and probably weird way of presenting things. I don't get to use english too often. So thanks for making a sacrifice.

I drive an -89 half ton Suburban with stock 10 bolt axles, 3.42 ratio.
When i bought the truck, it had 32" AT's and seemed to go rather decent. A vain man as i am, i soon bought 35" Cooper Discoverer's knowing it would be a most suboptimal setup. But it looks alot better with the 3" body lift so...
I'm not terribly worried about the TH700 because there's new clutch packs which got thrown in while i was in there replacing an exploded planetary gear.

Living in Finland brings all kinds of trouble if you insist on driving an american car. First of all, i did have the truck inspected and plated. I did not however manage to get approval for those 35's. Not yet anyways, but that was another thread a while ago.
But yes, i need to get numerically higher ratio diffs. Diffs alone would cost me around 400$ each plus probably having someone install them. Yes, it's expensive to have something heavy traveling across the world. Trucks being such a rarity here in Finland, i would compare it for you to drive a japanese domestic model 1975 Celica Liftback. Spare parts seem to be made of dinosaur sperm.
Although my truck is nothing but a mall crawler, i'd be happy not getting stuck on an icy hill or an occasional puddle of mud. So lockers please? That's where the money is, you know it!

There's a forum for offroaders here in Finland and it also includes a marketplace. Sure, you're welcome to check it out (www.offipalsta.com) but for no apparent use, since finnish is only spoken here in Finland. A whopping 5 million of us. I wish we'd just switch to speaking english. Oh, yes the axles... Back to it.
There's a person selling axles nearby (30 miles from me). I really feel i must share this with you, because the seller is far from your typical wheeler. She's a small blonde. Really. About 27 years old, give or take. She appeared lively and she's actually very easy on the eye, not that it matters and no one should be judged by their looks but sometimes, in some situations, looks can go a long way.
Anyway, i felt pretty dumb asking all the questions about the leaf springs i was buying earlier. It was hilarious. I get paid for fixing cars but the cars are mainly european and asian. Trucks are somewhat new to me. She was very open about her hobby and i could tell she knew her stuff. Her truck is a long bed k20 or k30 with a big block.
She had a matching pair (of axles, mind you) for sale diff-wise.
The 12 bolt is said to have an Eaton LSD and 4.11 diff ratio. Ratio is not what i would have wanted but alot better still than what i currently pretend of driving. And there's a bonus: she said there are new innards in the drums. Drums are not new, but mine are absolutely dangerous. The brake shoes have almost nothing left on them and drums are practically in two pieces. I can't believe they passed inspection! And as i mentioned about heavy items, 10 bolt brake drums would cost me 125€ each, plus a set of brake shoes 60€. So i'm pretty stoked about her offerings...

Obviously she has a front axle for sale as well. It's a 10 bolt with a Lockright, Yukon Chromo shafts and if i understood correctly, Moog Super Joints. Remember i'm new to this.
Needless to say it's also 4.11 ratio.

She's asking 400€ for the 12 bolt and 550€ for the 10 bolt. A bargain i would say, especially as i'm forced to do something (anything) to the rear brakes! She was willing to make a package deal back then, and it was months ago. Axles are still for sale. Checked yesterday.

As far as i know my 89 has 30 spline shafts which are supposed to be almost decent. I have no idea how old the pair is. What i'm most concerned of is, seeing someone posting a question about using spacers with a 12 bolt, are there significant differences between (some) 12 bolt axles and a 1989 10 bolt? I believe i'm going to have to get a hybrid u-joint and have the drive shaft lengthened by a couple of inches (to be measured). It will be convenient to count for the 4" lift springs i bought from her earlier at the same time.

So all this long-winded rookie nonsense was aiming for this:
Any thoughts regarding longevity of said axles and/or parts?
Is there difference in width 12 bolt vs 10 bolt?
I kinda like the way the truck sits at the moment, and i certainly do not want a narrower rear axle.

Thanks for reading and thanks for any input!

 

[dremu]

Your English is far better than my Suomi, I'd not have known unless you said. I'm still laughing over your analogy to dinosaur spooge. I'm sure we'd have the same trouble finding parts for a Volvo 303 or a Sisu or the like here.

Anyway, to your questions:

The 12-bolt rear is no stronger/weaker overall than a 10-bolt. The only reason to switch is if you can find a matched set with the desired gear ratio and/or in better condition, which both apply in your situation. Spline count on the front axles doesn't materially affect their strength. Longevity will basically depend on your driving style

IIRC, track width (wheel-mounting surface-to-surface, aka "WMS") is close or identical between the two. I vaguely recall that the 2WD axles had one shock mount different than the 4WD, so you might verify that the 12-bolt came out of a 4WD truck or has the shock mount moved. A good photo would also suffice to match it to yours.

I know having the rear narrower looks funny, but the factory did it for a reason. Whether that's a smaller turn radius or other reasons is up for debate, but I don't like spacers, so I'd leave it alone. If you have spacers now, they should still fit the other axle, as the bolt pattern for all should still be 6-lug.

Hope that helps!

-- A

 

[burber1989]

Thanks. Now i feel even better about the deal.

She told me she had installed those lockers her self and that kind of surgery is what would worry me. I respect her skills and attitude. She did also mention she had been wheeling those axles 4 times "in the woods", so i'd think the 12 bolt came out of a 4wd. And her having installed them onto her pickup would probably make matching shock mounts. She is an avid welder, or her husband is. There was all kinds of protective tubing welded that NASA would be jealous of.

And spacers, not for me. Having none at the moment and not planning to either. Strenth-wise they seem to be as dumb as a body lift.

There's a weird choice having been made regarding the wheels: front wheels are 8" wide and the rear wheels are 10" wide. I guess they are out of a van or something. Swedes have a little more to choose from so i'm surprised. Maybe the PO was in a hurry to get the truck running.
I only use 4wd when it looks like i might be getting stuck in snow (those discoverers do very little to help) so not using it on the pavement. Not really sure if it would be enough to break something in the long run but a different set of wheels is on my wish list.

 

[Blue85]

If the Moog Super Joints are the same ones we get here, they're nothing special. Better than cheapos, but not as desirable as Spicer. Aftermarket axleshafts are big money, though and a locker is worth something. Some of the 12-bolts came with a 1310-joint yoke, while 10-bolt rears usually had the 1330, so that's something to look at. Maybe ask if it's already been converted (it requires a special seal or something).

Right now the Euro and USD are about the same. Over here, a 1/2-ton rear would be maybe $1-$200 because of the locker and half-decent gear ratio. The front could definitely fetch a few hundred because of the aftermarket parts.

What you have to ask yourself is whether 4.10 is really the ratio you want long term. Of course don't take anybodies word regarding condition. Absolutely pull the differential covers and even check backlash, inspect bearings, etc. If the gears were set up wrong, it was run with a wasted bearing or water sat in the diffs, they could be junk. Also check the ring gear stamping for ratio, inspect the LSD and locker, etc. Like I said, don't take anybodies word for it - people often get confused on what they have.

 

[burber1989]

If the Moog Super Joints are the same ones we get here, they're nothing special. Better than cheapos, but not as desirable as Spicer. Aftermarket axleshafts are big money, though and a locker is worth something. Some of the 12-bolts came with a 1310-joint yoke, while 10-bolt rears usually had the 1330, so that's something to look at. Maybe ask if it's already been converted (it requires a special seal or something).

Right now the Euro and USD are about the same. Over here, a 1/2-ton rear would be maybe $1-$200 because of the locker and half-decent gear ratio. The front could definitely fetch a few hundred because of the aftermarket parts.

What you have to ask yourself is whether 4.10 is really the ratio you want long term. Of course don't take anybodies word regarding condition. Absolutely pull the differential covers and even check backlash, inspect bearings, etc. If the gears were set up wrong, it was run with a wasted bearing or water sat in the diffs, they could be junk. Also check the ring gear stamping for ratio, inspect the LSD and locker, etc. Like I said, don't take anybodies word for it - people often get confused on what they have.

You have a point.
No reason throwing money away just because someone thinks they have something special for sale.

When it comes to diff ratio and lockers i can't really see any options but to make a compromise.
I know i don't need to convince anyone but let's say i'm also trying to process all this. Kinda thinking out loud.

Installing ring and pinion: a professional is asking 700-800€ drive in, drive out. Includes labor and diff oil in both axles, nothing else.

Lockers maybe 600-700€ each here in Finland as far as I know.

Ring and pinion probably 300€ each not including bearings and such. Of course this would get me the desired 4.56 or 4.88 ratio but hey, i really can't afford it. Not now, not next year.

I guess i'll take your advice and check gear ratios and the overall condition of parts and try to live with it. The truck gives terrible mpg at the moment and i've taken every possible way to avoid unnecessary stopping. My simple math gives some value to 4.10 over the 3.42 although not perfect.
I find it impossible to part 2000-3000€ when some people say that's what my truck is worth at the most. And for the money i'd have to throw into brand new lockers and stuff i'd insist getting 14bff and D60

Thanks for awesome advice.

 

[campfire]

I don't think 10 and 12 bolts were used together from the factory (should be a D44 If it's a matching set). Has she told you where she got each axle?

 

[burber1989]

I don't think 10 and 12 bolts were used together from the factory (should be a D44 If it's a matching set). Has she told you where she got each axle?

Yeah, i don't think she mentioned anything about that, but i doubt they are from same vehicle to begin with. I'd say most likely she has acquired them over time and my understanding is that she had bought and installed both the gearing (s) and lockers herself. Hence i'm amazed by the low price she's asking for them.

 

[campfire]

Yeah, i don't think she mentioned anything about that, but i doubt they are from same vehicle to begin with. I'd say most likely she has acquired them over time and my understanding is that she had bought and installed both the gearing (s) and lockers herself. Hence i'm amazed by the low price she's asking for them.

How many competing buyers would she be able to find over there? Aren't these trucks really scarce? It sounded like much of your "standard" cost for this type of part was just the overseas shipping. Which wouldn't apply in this case.

 

[burber1989]

How many competing buyers would she be able to find over there? Aren't these trucks really scarce? It sounded like much of your "standard" cost for this type of part was just the overseas shipping. Which wouldn't apply in this case.

Competing buyers, well, apparently none so far. One guy was willing to buy a matching pair of ring and pinion but he needed them for 10 bolt front and rear. She's also offered to sell them in parts, which worries me. Luckily for me, there's not really demand for those kind of parts.
About the cost... She has paid serious money for them, just like i would have to if i were to buy them new. There are two vendors here in Finland and i can't see them competing in prices.

I know you can never get your money back selling your truck, in whole or otherwise. But this, i believe is a bargain. For me anyways.

 

[campfire]

It's a bargain this time. Your time to sell will come someday.

 

[burber1989]

It's been a while. For a reason i might say...

Let me start by saying this is probably more like Situation Room stuff but it's all connected.

I was finally going to go get them axles after having done 77 hours of welding for the money. Yeah, not exactly an amazing deal but there i was. My former boss had asked me to help him out and this being a small town you really don't get paid well.

Anyways... I developed strange symptoms and rather severe stomach pain and had to go to a hospital. They let me suffer pain that was excruciating at that point until they decided to send me to cat scan. I was told i had a colon burst. Apparently there was stuff mixing in a horrible way and an inflammation was taking over. The surgeon said i would definitively have died if i stayed home. Luckily i'm such a pussy. They rushed me onto operating table and the next day i woke up with a colostomy bag. At first they told me it was only going to be for a month. The next day it was two months. Well now it's been six. But yeah, some blockage and/or inflammation was the initial reason, and they removed 4 inches of intestine. I'm still waiting to have the stupid bag removed but it's holiday season and they only operate on cancer patients.

There i was lying on a hospital bed organizing the axle pickup. My previous boss volunteered and for what i know, it had been more chatting than inspecting parts. I remember Blue85 giving good advice but i wasn't there and he's supposed to be pro.
I was released from hospital after 10 days and i was a wreck. It was slow and difficult to move around and i couldn't have done it if it wasn't for my brother. He drove me around for a week and after that i took the bus to get groceries. My truck only had first and reverse gear. Again. I managed to fix it by thoroughly cleaning the valve body once i'd regained my mobility to some extent. It was super fun worrying about the truck when you hurt physically and you're emotionally a mess.

Of course i was on sick leave. It's always paid here, no matter what. We had friendly relations in the company. Until then, that is... My boss told me he had been told by his accountant to let me go. We all knew i was in for a long recovery and unable to work. So he let me go and told me he'd take me back when i'm well. Gee thanks...
Having done welding etc for my former boss he asked me how much i was paid. He threw almost 30% on top of it and also got me a place to stay. So here i am, back in the old company, waiting to get to work after the removal of the colostomy bag.

I finally got to start changing the axles and it actually went surprizingly well. I started with the rear axle since i usually only drive on 2wd. I had bought the conversion u-joint and i also had new leaf spring u-bolts as well just in case. I had to weld up shock mounts as well. There weren't any but i knew that. Emergency brake was not bolt on at all. Some different cables so i just zip tied them out of the way for now. Off to test drive!
Umm... The truck feels really sluggish... Let's take it to freeway and see what's up with it. On a freeway it shifts to overdrive some 3 to 5 mph later than before. Are you kidding me???
Back to garage and lift the rear end up, only to calculate 3.08 ratio between tires and drive shaft. Pretty far from advertised 4.10!
At that point i was super pissed and decided to go home and sleep on it. The next day i changed the old axle back and had a conversation with the seller. She and her husband did not believe it at first but confessed they had never looked into it. The axles were sold to them as 4.10 years ago and they obviously had no idea. They refunded me and all is well, except that i'm back in the same situation. Lots of fun working on axle swap with a colostomy bag and having trouble moving.

I first met this couple when i bought lift springs from them a year ago. I soon found out that the rear springs were 4" shorter than mine. I had no idea. Once again...
Mine are 56" and for what i know now, some half tons were delivered like that. Am i not the lucky one! At that point it seemed i'd have to have them modified for 400€ a pair. Not really what i was after, having only paid 180€ for the kit, front&rear.
Somehow it appeared to me i could move the spring hangers 4" onwards since these new springs are symmetrical and the original ones are asymmetrical lengthwise. There's even holes drilled ready on the driver side. Funny though, not on the passenger side.
I had measured and bought all the bolts you could possibly need and i was ready to install the lift springs.

I noticed it would be wise to remove the gas tank, at least partially, to get to install the hanger bolts. There was no room inside the frame. I don't know if it's different on a Blazer. Well, i ended up spending almost three hours and most of my energy trying to get the nuts on the tank bands to open. There's no room for the usual power tools and no, we have no induction heater, not even asetylene torch at the moment. That's when i realized not having seen the power drill on the tool shelf, so no point in disassembling anything beyond that. There was no way i could finish the project, because there were holes drilled ready only on the driver side. I was pretty mad at my boss for having spread the tools all over town. He has two garages and the other one is his favourite. We all know where the tools are...

A week later i had armed myself with cutting disks for the 2" pneumatic angle grinder which my boss never buys. I know, they are rather expensive and never last long. I ended up buying them on my own and drove to the next town only to be told they had none. I asked a friend of mine to pick some up from another town when she had business there. I also bought my own power drill
With the right tools I managed to remove the tank bands no problem. Then i proceeded to removing leaf springs and knowing i'd bust the rivets anyways, i started from the front eye bolts. I suppose i should have known it wasn't going to be easy. Anything made of steel in 1989 probably isn't going to give up easily in 2017 if never taken apart.
I managed to remove the inside nut and the bolt seemed to move a bit as well, but to my great disappointment it was stuck on the metal bushing. There was no way it was coming off without an impact hammer (no, we don't have one) or acetylene torch. I could have just cut everything to pieces but not knowing how those particular lift springs work on a Suburban, i just couldn't justify the risk. The garage must be left clean and empty every night because it's a place of business after all. I'd hate to have my truck paralyzed on the 4 post car lift when there are customers lining up at the door.

I can't take this anymore. Not for a while at least. I'm afraid i'll completely loose it if things go sideways once more. My nerves are shot. It's probably for the best to wait until my boss has the time and energy to help me out on this.
Thanks for reading.

@Martin: I need you to say something nice

 

[campfire]

You have good perseverance. Take a break and come back when you're feeling more refreshed. It will be fine.

 

[campfire]

Our designated Martin is @82355, FYI.