Exact fit replacement for the notoriously weak D35 shafts. And I mean exact -- I measured all along with a micrometer, side by side with the originals. These are identical. See my install thread with pics, starting at Post #30, Installing a TrueTrac etc.
If you haven't installed such shafts before, you'll be amazed how easy it is. Just remove the wheels, remove the c-clip from the old shafts, slide out the old shafts. That's it -- just reverse the process to install the new ones. Super swift. (That's if you don't need to install new bearings and seals; your decision.) How can you not do this?
They have held up fine for 2+ years in my Jeep, which sits on 31x10.5 BFG MT2s, has a TrueTrac, and is offroad 100% of the time.
I have seen various estimates of how much stronger these are than the originals. 30%? More? But everyone agrees: much stronger.