Dave and I just got off of the phone discussing his work on comparing the front and rear carrier and ring and pinion dimensions. To sum it up, the whole 3rd member with carrier will fit the front axle but some kind of bracket will need to be fabricated to prevent axle wrap.

Another possability that [color:"blue"] might [/color]work would be to put the rear carrier and it's 7.5" ring gear into the front 3rd member housing [color:"blue"] and [/color]put the pinion gear from the rear in too. We don't know for sure if the pinion will fit but the bearings have the same part number.

and the pinion gears seem to also have the same length, so it seems like the rear pinion wouldn't have any trouble being used in the front 3rd member housing. ron mentioned there's the possiblity that the reason the front and rear pinion flanges had different part numbers might be because they have threads cut into them to thread onto the end of the pinion. if this is so, you would also have to use therear pinion flange in front and this also creates the possibility that it could spin off if the pinion nut ever got loose, due to the direction difference in the forward riveshaft rotation. but since they don't get loose when in reverse, when in the rear, it probably isn't as big an issue as i'm making it. the only other difference is the area in the cast 3rd member housing for the pinion gear head seems to be larger in the rear 3rd member housing than the front one, to allow for the larger gear head on the rear pinion. this may not be a problem either as the front one still looks like it has plenty of room.

if the 7.5" gear fits the front housing, i have to wonder why it wasn't used. it would have been a HELLofalot cheaper to have one size and cut of gear made than two that don't fit each other, but fit in the same housings. if Kia had done this, it would have made all this work we are doing now unnecessary. it would have made the aftermarket twice as easy and there'd never likely be a question about the strength of the front differential. but then the CV's, if they aren't already would be the definite weak point.

[img]http://pics.montypics.com/fledgling666/2004-10-23/[/img]

Are you absolutely sure they do not line up, ie not indexed with 2 or 4 holes slightly offset from even spacing around the perimeter of the ring mounting flange, or is the PCD totally different (Measurements from both would be nice to know...)? If so this would indicate that the diffs are in fact different and that we will only have the option of going with the 7" 26 spline ARB front diff fitted to the rear housing, possibly at the cost of breaking them every so often, (remeber the vehicles the front diffs came out of are half the weight of ours) , unless ARB do a redesign to accommodate the different PCD for the 7.5" R&P on the rear. (*** this is all contrary to what I have told ARB <img src="/forums/images/graemlins/shiner.gif" alt="" />)

It does however open up the possibility of a stronger front end using 7.5" R&P in the front, and whether it would be worth it to get ARB to make a 7.5" 26 spline diff only, allowing us to put the ARB diff in both ends with the addition of a 7.5" R&P set for the new rear (transferring our used 7.5" to the front). The only requirement would be to have the rear axles resplined for the later year rears.

Hi Gary,

Another possability would be to make the locker with the o.d. to match the 7" ring gear and drill the ring gear mounting flange with 20 holes, 10 for the 7" PCD and 10 more for the 7.5" PCD. A shim ring would be needed to center the 7.5" ring gear. By the way there is some indication from drawings in the Service Manual that the 7.5" ring gear mounting holes are not evenly spaced.

(Dave--please check both front and rear ring gears for spacing and PCD)

The lowest user cost and best manufacturing inventory would be if the same locker could be uesd in either the front or the rear along with the origional front and rear ring and pinions and 3rd member housings.

The lowest cost for puting a used rear 26 spline LSD in the front would be if the 7.5" ring gear can stay on the diff and the rear pinion can be transfered to the front 3rd member housing.

I hope the pinion hypoid offset is the same in both front and rear to allow proper mesh if the rear ring and pinion has to be installed in the front 3rd member housing.

This is unlikely as the third member housing may have been altered front to rear to allow for the larger ring and therefore the less "reach" required by the pinion.



Will most likely be different for the above reasons (think of it as "scaling up")

If the overall differential dimensions are the same (as per the Eaton diagram discussion earlier) then a double drilled ring mounting seat is a possibility. As for the requirement for a sleeve for the larger ring, I wonder if this would be necessary given the very marginal lip that appears to be present on the existing rear diff (Daves photos), looks more like machining of the casting than an actual purposeful locating lip.

Hi Dave,


Only trying it will tell. It depends on the exact location of the pinion bearing in the housing. From the cross section of the housing in my manual, there is enough "meat" in the casting to move the pinion depth position over 1/2" but it only needs to be moved a maximum of 1/4". From a machining standpoint, boring out the housing 1/4" less depth would be easy.



Again only trying will tell. From a CNC machining standpoint, it would be slightly easier to use the same offset rather than "scaling up" since the fixturing would not need to be changed.



We would absolutely need a spacer ring. The ring gear needs to be centered within a couple of thousands of an inch and you could not do that with just bolts that don't have a cone seat.

Hey dave, sorry I didn't get back to you, I don't check the internet after 3:30 on Fridays, that's when I get off from work. I can get down there Saturday at about 11:00 AM. How would that work out for you?

that's fine, pedro, i should be home. if you came sunday, though, we could go 4 wheeling with my club.

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as for the rear pinion working in the front- i will see about getting mine loosened sometime this week to see if it will work.

the ring gear bolt pattern is definitely different by a few millimeters. sorry the pic aint that great, but you would not have been able to see the holes very well if i'd taken it back a little. there is one bolt holding the rear ring gear onto the front carrier in that photo. both ends need to be almost a press-fit, i think ron referred to it as an interference fit, either way, you cannot get the ring gear onto it's respective carrier without tightening all the bolts down, pulling it to the surface. now, ron, there is no play at all in the ring gear once all the bolts are in (but not tightened), so i doubt there could be a problem with it being off-center.

here's my suggestion- have ARB make a 7.5" locker and i will supply all the 7.5" rings and pinions everyone needs for as little as i can charge, without going broke. i with the difference between the 26 and 28 spline rear ends, i wonder if a sleeve can be made for the locker to fit either. said sleeve would be a weak point, for sure, though. if not, i wonder what the cost would be to run a set of 26 spline and 28 spline. and if none of this pans out, i wonder how hard it would be to build a lock-rite for these diffs. and how many would be interested.

gimme some time to find out about the pinions and i'll get back to you guys.

Hi Dave,

You might be able to use your carrier bearing adjuster to hold the pinion flange while removing the pinion nut. The FSM shows a special tool to prevent it from turning.

If a 7.5" ring gear is on a 7.5" carrier it will be centered.

If a 7" ring gear is on a 7" carrier it will be centered.

If a 7.5" ring gear is on a 7" carrier it will need a shim ring to be centered.

Here is a similar spacer to put Sidekick ring gears on a Samuri diff: spacer ring

I don't think there is enough diameter difference between the 26 spline and the 28 spline axles to make an adapter sleeve. Even if there was, it would be more expensive to make than a side gear with the proper splines.

Could you tell if the holes were evenly spaced on both the 7" and the 7.5" ring gears?

Hey, Sunday sounds better. Maybe I can convince my compadre to take his Toyota. What time do you guys get together?