Other Dana 30 lunchbox locker in a subaru front?

[BonkersBaja]

Why Dana 30? I've spent the last couple of years trying to figure out an ideal axle stub to pair with the Torque Master VA2 which fits right into the Subaru transmission differentials. There is no simple solution. One possibility, Torque Masters would need convinced to produce a new model (VA3?) with 28.5mm 25 splines for front diffs... which they seem opposed to. A second possibility is for front inner CV joint cups but with 26mm 25 splines to be sourced, probably from a Chinese manufacturer. That would undoubtedly require ordering a large quantity.

So, rather than searching for an axle stub to mate with an ideal locker, I began searching for an ideal axle stub and a locker to match it. Dana 30 is perfect. They're larger, stronger and the lockers often cheaper. Unlike the torq Master lockers with 26mm 25 spline, the Dana 30 is 29.3mm 27 spline. Machining the diff case for Dana 30 (doable, I've checked) and also the inner CV joint cups to accept Dana 30 axle stubs will produce lockers and inner CV cup shafts that exceed the original strength of the Subaru parts.

Any lunch box locker for Dana 30 could be used. Torq Masters because they have a great design. Powertrax No-Spin for it's syncronizer. Or a DL30-27 because they are very inexpensive (see Ebay item 316458899811). The Dana 30 shafts are a bit expensive outside of the USA due to shipping (see Ebay item 371451691121). That is the only iteration of Dana 30 shaft that will be suitable for the machining necessary.

I am curious about the WRX R180 27 spline. They are likely similar, but I think not a direct fit. Would somebody measure the spline diameter on a rear inner joint cup of R180 axle shaft for me? I think they're the same spline as the outer wheel bearing splines but I don't know for sure. Also the diameter of the polished and oil-grooved bearing surface would be useful.

I expect to build both a 5MT diff and one for a 4EAT during May, 2025. The build should also work in 6mt and CVT.
If anybody else wants to give it a try, I would be up for sharing guidance and ideas back and forth. I have many more details I can share.

 

[BonkersBaja]

Well, I've been playing in earnest with making a rear axle work in the front to get a VA2 locker to work inside of a 4EAT. It is barely, barely doable. A rear axles from Tribecas can be used as the inner joint is larger (roughly same diameter as a front cup) and, more importantly, it's outer CV joint can be swapped for a front outer CV joint as it's internal splines happen to be the same as many pre 2014 models.
There is a lot of obsessive metal lathe work (though not necessarily difficult) to get the stub shaft to reach inside the transmission far enough to click into place. Spacers (I use nylon) between cross shaft and outside couplers to prevent outside couplers from moving inwards. The bearing section of the stub axle will need widened which will narrow the shoulder for seating the rubber oil seal. The bearing portion will need cut (and finally polished) approximately 6mm wider. Sneak up on it as you test fit for the snap ring to just barely click into place. The remaining seal portion will be barely wide enough for the seal. A 32x50x8 seal together with a 1mm shim can replace the factory 32X50X9 giving a 1mm better margin.
Much massaging of the sundial bearing adjuster will be required. Remove all but the outermost 6mm or so of the external adjusting fins to allow the cup to come up as tight as reasonable to the rubber seal. The dust slinger will have to be removed or greatly modified to get the cup to go in deep enough. Then the bore for the bearing race on the underside will need cut deeper until the rubber oil seal is seating well on its section of the axle stub. Again, sneak up on it. Also, the oil grooves will need to be extended throughout the new width of the bearing surface. These oil ways aren't precision and can be carefully done freehand with a moto-tool with a small cutoff disk.
This will work on a great many of the pre 2014 models. You would need to do due diligence on axle lengths and internal splines. If the font axle of the Tribeca is very close in length to your front axle, then the mod should work as long as the internal splines of the CV are the same (24.5mm OD, 30 splines).
The work involved to use a rear axle in front makes me suspect that the Dana 30 will be the much better option that can be adapted to probably any model. The challenge to the Dana 30, aside from getting shafts shipped worldwide, is the more technical machining. I'll post further details and special tooling concerning the Dana 30 as the work proceeds.