No, it pulls solely on the stub axle shafts, and those are indeed held inside with a clip, but the risk is minimal really... you'll feel the spring compress as you are mashing the flange down.
It'll feel like you are compressing a spring and then suddenly it'll get solid and just stop. That's it. There should be enough groove exposed for the circlip at that point and no need to try to force the flange into the trans any further.
All of the forces are being put into the stub axle, even from the spring which is pushing (indirectly) against the diff carrier... the spring is shoving the diff carrier away while the stub axle is connected to the flange that is trying to push the diff carrier away, so in the end, all of the force needed to compress the spring is sent into the single 2.0mm or 2.3mm snap ring that holds the stub axle into the diff carrier.
Once you get the flange clipped in place, the spring tension will continue to want to pull the stub axle out of the diff, but that snap ring inside will hold.
VW presses the circlip on, they don't use pliers to expand the rings to install them. I don't know that they use a M10 bolt to pull the circlip on though.... I was under the impression that it was pressed on directly, they just start shoving the circlip onto the stub axle with the flange... the stub axle won't be pressed into the diff due to the spider gears and so on inside, so it is solid, and they simply drive the circlip on and call it done.
One of these days I'll try both methods... driving the circlip on with a socket and M10 bolt (which is the same as pulling OUT on the stub axle), and then driving the circlip on with just a socket, no bolt, so the forces won't be pulling OUT on the stub axle, it'll be shoving it INTO the trans (where it will stop and the circlip should be driven on easily).
Just thinking about it, it would be a massive PITA to try and hold a nearly-built 70 lb. trans sideways on the press so I can press on the circlip... that method may or may not get tested:laugh:
