Lets just be clear, a D44 is a Dana44 ( Dana being the company that makes them ) as factory fitted to a JK Rubicon.
I'm assuming whats wanted is a stronger axle assembly.... which of course could be, but doesn't have to be a genuine Dana44 which i suspect would cost megadollars from Jeep.
There are other aftermarket housings that take 44 internal and bits but are not D44's in the true sense of the word... e.g. Teraflex or ProRock or Dynatrac etc..... They are improved versions of the D44.
Yes its a bit confusing but if you keep mentioning "D44" and "Rubi diff" then people will assume you want a factory D44, when i suspect an aftermarket replacement is what your really after.
You can also go the D60 route which is another topic in itself. However these conversions are still expensive, HEAVY, WIDE and can have wheel diameter / offset issues. They did make sense once upon a time when the aftermarket hadn't started making 44 replacements, but IMHO nowdays with the choices in 44's they make less sense unless your running an engine conversion.
Of course you may be able to get a second hand genuine D44, which would be cheaper than aftermarket BUT whilst they use stronger internals than a D30 unfortunately they share the same axle tubes C's, and mounts as the D30 and obviously have the same bending issues.
These aftermarket housings take parts designed for a D44 ( axles, crownwheel and pinion, Outer C's etc etc ) but are stronger everywhere. They have large center castings, bigger diameter axle tubes, bigger C's, tougher suspension mounts and and... ).
Everything outboard of the inner C's will swap from a D30 to a D44 or T44, Dynatrac etc.... so you reuse your brakes, bearings etc. Control arms, steering all remains the same.
But you will need a 44 crownwheel and pinion, a locker to suit and axles ( please read the information about the issues raised with non genuine lockers and axle lengths carefully ). You'll also need an appropriate pinion flange to suit whatever front driveshaft you running.
No matter what aftermarket path you go down your up for a TRUCKLOAD of money upgrading from a D30 to any 44 and if you don't use a genuine locker will end up with aftermarket axles ( RCV )which IMHO are best avoided.
It certainly takes the edge off "saving" money by not purchasing a Rubicon in the first place, a D44 to T44 upgrade isn't anywhere near as painful
/End Rant
