If using the BPP adapter the backlash is adjustable with the Himax in the GWS Box. You might check that pinion for a bur inside at the shaft end, I had a stainless pinion with a bur that kept it from going all the way on. You could heat up the pinion a bit, 200 F would real safe, heck its brass drop it in some boiling water and slip it on the shaft before it cools much.