Pre-release -- work in progress, but good info, I think.
OK, here's the straight information on the differentials, from two sources: the Hollander Salvage Yard Interchange Reference and my own junkyard testing. If you find any exceptions, I'd love to hear of them, so please email me at email@example.com.
Three types of Isuzu corporate differentials exist: 8-bolt, 10-bolt, and 12-bolt. The number of bolts refers to the number of bolts holding the ring gear to the differential carrier and not to the number of bolts holding the third member to the axle housing. Note that on this page, unless otherwise specified, Corporate X-bolt means ISUZU Corporate X-bolt, and not a GM Corporate X-bolt -- these terms are NOT interchangeable.
The Dana 44 is not an Isuzu-manufactured axle, and we don't have a lot of information on it. Similarly, the GM 10-bolt differential is not an Isuzu-manufacturedaxle, so we don't cover it in depth here. Most products made for other these axles for use under trucks of other brands should work for the corresponding Isuzu axle, as well, though some may require creativity and modification.
Below, the lines are grouped according to what Hollander says will interchange. According to Hollander, the 89 Amigo front differential would interchange with a 94 Passport but not a 93 Rodeo.
What's this locking/non-locking business? Dunno for sure. Odds are that it is Hollander's nomenclature for the Isuzu Limited Slip Differentials (LSD) that certain rare trucks came with. No one that I've talked to has ever seen a factory-locking differential for these trucks. I'm not honestly sure that is what Hollander is talking about when the say "rear locking," but that's my best guess.
My guess is that when you factor out the antilock brake differences (tone ring, sensor, etc), this list of interchanges will match the one above in General Applications. Thus, in the example I cited above, with the 89 Amigo front differential that Hollander said would interchange with a 94 Passport but not a 93 Rodeo, my guess is that the 89 differential WOULD interchange with one from a 93 Rodeo - and vice versa. You just might not retain the anti-lock braking functionality.
If you find any exceptions, I'd love to hear of them, so please email me at firstname.lastname@example.org.
Well, first keep in mind that if you have anti-lock brakes and want to keep them, you need to find a donor truck with antilock, as well. Also remember that you need the front and rear gears to be within 2% of each other if you ever want to engage 4x4 and not destroy expensive drivetrain parts.
You should be able to swap any differential for another if it has the same number of ring gear bolts, regardless of whether it originally came in the front or the rear. Since 8-bolts were only available in the font, and 12-bolts were only in the rear, they are pretty simple. But 10-bolts seem to be universal - they all use the same 17-spline sidegears. I say this after test-fitting an actual 17-splined axle into 20-25 front AND rear 10-bolt differentials at the junkyard.
ARB Air Locker
ARB currently only makes air lockers for the Dana 44 and Isuzu Corporate 12-bolt, more on this soon
TrueTrack Detroit Locker
Works only on the Dana 44, more on this soon
TrueTrack Easy-Locker and Gearless Locker
Currently only applications for the Dana 44, but there may be some exciting developments on this soon - wouldn't it be cool to have Gearless Lockers for 10-bolt and 12-bolt Isuzu corporate differentials?
As for crossfitting lockers, there's been scads of "I heard that...." and "I wonder if..." floating around -- I'm looking to get to the bottom of this. If you have hard anecdotal evidence (i.e "I did it and it worked for me."_ please email me at email@example.com and I'll add you experiences. If you know somebody who has done it -- cool, send me their email, or there name and phone number. I'll post more here as I know more.
Proven crossfits include: