I read this article here: http://www2.zukiworld.com/feature_tsb_shiftontheflyremoval/ which outlines a SOTF elimination method, but all that article is saying is just replace the entire front axlehousing with one from a Sidekick. That wouldn't make any sense in my case since I have the steel housing and a Sidekick one would be aluminum. So if I want to run the steel diff without the air-shift, but also have the 5.13 gears from a Sidekick, what do I need to do and which parts do I need to find? And as a bonus question- would I be able to run a front locker for a Sidekick when this is all said and done?

Or would it be simpler to just find a steel 5.13 diff from a wrecked automatic XL7 and swap it in, and do the zip-tie modification to bypass the air-shift? If you wanted to, how would you go about putting a locker in that?

Zip tie mod outlined here: http://www.zukiworld.com/forum/suzuki-grand-vitara-vitara-chevy-tracker-(gen-2-platform)-1999-2005/damn-i-think-i-really-broke-something-now/

I used he front and rear thirds from a sport96-98 to get rid of SOTF, but I also used the banjo and CV axles and just plugged the hose for the air pump and put locking hubs on. The 2001 xl-7 that I swapped the motor with was aluminum, I believe the steel front diffs are only in 99-03 GV that are standard. I've  looked at a lot of GV and xl-7 and all autos were aluminum. you should be able to run a locker in the front but arb in the front would be best, I know its pricey but you aint going to need it locked all the time I believe unless it a trailer queen. Another thing to consider is that if you are thinking of putting it into an XL-7 you have to match thirds front and rear and the XL-7 rear driveshaft is 3 bolts not 4. I don't know what gears your running now but it was easier for me to swap out the whole front diff if I had a steel front diff I would have swapped just the front third. And you will have to be 26 spline so from 95-98, 89-94 have 22 spline but you probably knew  that

Sorry, I should clarify, my 2003 XL7 is a manual, and already has the steel front diff. I just want to convert to 5.13 gears for when I run 31's. Basically I should just find a 5.13 third member from any 96-98 5-speed Sidekick, take my third member out, and set it up so the gears from the Sidekick end up on my steel 3rd member. Then I should at the same time figure out a way to permanently engage the collar for the front diff engagement. But weren't all 04-06 XL7's equipped with the steel front diff?

I agree that an ARB would be the best option for the front especially since this is a daily driver, need to be able to steer on icy roads in winter! But since I wouldn't be using the 3rd member, only the gears, from a Sidekick, I'm not sure if the locker would even work.

The rear axle is completely different from all other Suzuki 4x4's so the easiest thing to do there is just find an auto XL7 and swap the 5.13 third member in.

Found some more info that was very helpful:
http://www.zukiworld.com/forum/technical-discussion-performance-modify/gv-front-diff-issue-and-air-locker-install/

Basically a front carrier or locker from a Sidekick will work in the GV or XL7 front diff. If I want to use the steel 3rd member piece then I'd have to get the Sidekick gears set up in the steel piece. I need some clarification as to which shafts to use though. My memory is a little foggy, but, on my 2001 Vitara I did a similar setup years ago, and I think I used the Sidekick 3-bolt driver's side shaft inside the axle bolted to the original Vitara driver's CV, and then a passenger side CV axle from a Sidekick Sport.

why not just find a front third with 513 from a 96-98 and a rear third from a xl-7  auto swap that in and add locking hubs . I had a 2001 xl-7 that was auto and could have saved you a bunch of $$ as I would have given it away. I think that the passenger  side CV axle is the same length. like I previously said I used a sport front diff and axle and swapped it all out because it was easier for the gear swap

My XL7 has the steel front diff, so I'd want to take the 5.13 gears and get them set up in my steel 3rd rather than just plugging in an aluminum 5.13 third member. I don't want to downgrade to aluminum. I am also trying to get rid of the air-shift-on-the-fly at the same time since I bought manual hubs for the truck already.

Update: this is what I ended up doing. I bought a 5.13 rear diff from a wrecked automatic XL7 and plunked it in the rear axle, easy. For the front, I got an aluminum 26-spline 5.13 front axle from a 96-98 Sidekick 5-speed, removed the differential parts from the housing and 3rd member, removed my steel front 4.30 axle from my XL7, removed the differential parts from the housing and 3rd member, got the basic differential setup kit from Low Range Off Road so I had all the pinion shims I might need and a new pinion crush sleeve, pinion seal, and pinion nut, then swapped all the guts from the aluminum Sidekick axle to the XL7 steel axle. I found a service manual online for the complete drivetrain on our vehicles so I had all the specifications on hand for the job. I used the 3-bolt inner shaft from the Sidekick, and the driver's side CV from the XL7. I ran into trouble with the passenger side though. My plan was to do as the SOTF eliminator instructions on the main page say:

2. Remove the GV’s stub/ CV cup and replace it with the stub/cup off the Kick, making a “hybrid” CV shaft. Use the new clamps on the boot.

So I had the passenger inner stub from the Sidekick diff that I got from the wrecker as well. Took both inners apart to swap the Sidekick inner onto my XL7 shaft, and it turns out the XL7 CV joint is larger than the Sidekick one, so it does not fit in the cup! I then took the CV joint fully apart and tried to swap the inner race of the CV onto the half-shaft, which also didn't work because the half-shaft on the XL7 is also bigger. Ordered a 24" compressed length complete passenger CV for a 98 Sidekick Sport. Will compare the length of the stub to the XL7 one to see if it's gonna work or not. I guess it would also be possible to cut and weld a stub from a Sidekick to the cup from a XL7, not sure how strong that would be though.

the CV axle from the sport will be longer than the stock CV axle from the sidekick. the sport frame was the platform for the 2nd gen I can measure my stock passenger CV axle from my 2002. I used the passenger side CV axle from the sport, mind you I also used the front diff cause I broke the first one. keep us informed

Yes, the CV on a Sport and on a 2nd gen are the same overall length (24"). BUT, the big difference is the length of the part that goes into diff. On the regular Sidekick and Sport, which do not use the air-actuated diff, the stub is 3 7/8". On the 99+ models, the stub is 3 1/2". This mirrors the difference on the 3-bolt intermediate shafts between the two models as well.

So the Sport CV will work for this application, but I'm worried that it will be a chronic weak link in the system since it is likely built to the smaller dimension and torque requirements of the 4-cyl Sidekick. Maybe I will chop and weld the stub from the Sidekick onto my XL7 shaft as a spare.

EDIT: took some measurements with a digital caliper and came up with the following:

XL7 inner CV cup outer diameter: 3.1" ,  inner CV bearing race outer diameter 2.396"
Kick inner CV cup outer diameter: 2.93", inner CV bearing race outer diameter 2.3"

Difference between XL7 and Kick inner CV cup outer diameter = 0.17"
Difference between XL7 and Kick inner CV bearing race outer diameter= 0.096"

So we're talking about a difference of less than 3/16" on the cup OD, and less than 1/8" on the bearing race OD. I'm not even sure why Suzuki bothered making such a small change....but the fact that they still did makes me concerned that anything less won't last in the long run.