LUVTruck.com

I have been suprised this hasnt come up before. Recently i have come acrost some pics of the Isuzu 12 bolt axle (whats in second gen troopers). The only way to describe them is stupid. Why a truck the size of a trooper needs an 8.6" 12bolt axle is beyond me. And also the ring and pinion make the 8.5" GM 10bolt and the Dana44s look like childs play. Add that to the fact its a third member axle and the fact that theres a few of floating around for cheap, and i think its a underestimated axle. Gearing is vary limited (4.55 and 4.77 factory) but they bolt right up and have handled small blocks and 38" tires. I realy think for the budget build 350 swap this is a better axle than even a 8.5" GM 10bolt. Just thought i would through this out there, ill be running one behind the Cadilac so ill let everyone know if it holds up as well as i hope it will.

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1980 LUV 4x4, going under re-construction...

just to add to the info here on the Isuzu 12 bolt,

It first appered in late '87 behind 2.6L powered Troopers, and was used up until 2004 in the Trooper and Axiom. avalible gear ratios were 4.30, 4.56, and 4.77, Tera Gears makes a 5.38 ring and pinion set for it as well.

Added bonus, they ALL came from the factory with disk brakes and could be had from the factory with a limited-slip diff(look for the G80 code on the options plate when looking for one)

Hope that helps!!! I'm planning one putting one in my Luv when I do the 2.6/MUA swap(and then getting a 4.56 third from a 86 or 87 Trooper for the front end)

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'80 Luv 4x4, 3" BL, 1.5" SL, 32/36, 2.25" exhaust...and fuzzy dice.
'95 Toyota 4Runner Limited 5-Speed.

i thought the axioms ran Dana44s like the rodeos. And also i didnt know they came whith 4.30s either, guess that was a ratio for the V-6s huh.

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1980 LUV 4x4, going under re-construction...

I think 4.30s and even 4.10 gears may have come in some of the pickups. They stuck 10 bolt rears in a lot of the 2.3L powered 2WD trucks even after 87 when the 12 bolt arrived, but I think they put 12 bolts behind 2.6L motors even on the 2WD pickups. You can also find 12 bolts in Amigos, non-XS model 2wds even, so that might explain the lower number gear options. Those little wheeled 2wds needed something to help them run down the highway.

so the 12 bolt is a basic bolt in like the s10 rear? also do they all have disc's? if they just drop right in, id like to put one in the pup when i build the 327 in my garage. the 456s wouldnt bother me either. gonna be building the 327 for high revvin adn it gonna have a 4 speed. oh, do they make posis or lockers for the isuzu 12 bolt?

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"but its that gut feeling of you're drawn to what feels right for yourself and what you're passionate about..."

look for the G80 code, thats the factory posi! yes they all had disc brakes, and yes it is a basic drop in like the s10 10 bolt

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'80 Luv 4x4, 3" BL, 1.5" SL, 32/36, 2.25" exhaust...and fuzzy dice.
'95 Toyota 4Runner Limited 5-Speed.

As rezkid said, G80 option code (found on a tag under the hood on the firewall) on the Isuzu donor would mean it has a limited slip. ARB still does make an air locker, and a Lockrite locker used to be available. If you don't mind a little tire wear, you can always take an open diff 12 bolt and weld it into a Lincoln locker. There are quite a few of the Isuzu 4x4 guys running around with welded rears, some even see fairly regular street use.

yeah i was reading about grampa on pirate 4x4 running a 289 V-8 whith a 4speed and 36x12.50 swampers on the Isuzu 12bolt and i think his is welded too. Thats what inspired me. And ill probly be welding it, this car wont be a DD.

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1980 LUV 4x4, going under re-construction...

That was exactly who popped into my head too. There is a fair bit of evidence out there to say an Isuzu 12 bolt can put up with some serious abuse, welded or not. It is definitely a major part in my master LUV plans: 2.6L, 5spd, 12bolt.

I put one in my 4x4 recently. Here's the link:

http://forums.luvtruck.com/viewtopic.ph ... highlight=

I did it for the gearing and disc brakes more than the strength.

You can see it was a fairly simple swap. The only hassle was the driveline. I ended up welding it myself and just having it balanced at a shop.

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You went there in that?!?!

yeah i read your post and it should help on that aspect of my project

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1980 LUV 4x4, going under re-construction...

Does the tag also have the gear ratio or do you find it somewhere else?

The tag under the hood will only list the option codes, G80 being the LSD one. There is also a wide tire option and a code for 4.77 gear ratio. 4.77 code is S2J, but if the donor has the wide tire code it will have 4.77 gears but may not have the S2J code on the firewall. Supposedly there is a sticker on the doorjam that will read 31X10-15 for the wide tire option, but I have not found if there is also an wide tire option code for the firewall tag.

From what I've read, 4.77s exist only in 89-90 Troopers, and are found in most all RS model (Short wheelbase) Troopers. All other Troopers will have 4.56 gears. Odds are fairly good you won't see 4.77 gears, but I hope all that info comes in handy to someone.