What kind of puller are you using? If you got the one that looks like a disc with bolt holes in it that typically works pretty good. If you got the one that's like a steering wheel puller (what I used) you'll need to get shorter bolts for the two that go into the gear so there's not so much wiggle room as you turn in the center bolt of the puller. A hint, tighten the bolts into the gear as far in as they will go in keeping the puller flat with the gear (with the main bolt on the puller all the way out) then spray the main puller bolt w/WD-40 or like and twist it in till it's almost impossible to turn. Whack the end of the puller bolt with a hammer, turn the bolt in a bit, whack, repeat. Make sure the bolts securing the pump to the case are almost out (at least threaded back in 2 turns) so the pump doesn't "launch" when the gear lets go. Some guys have had to use a little heat. If you need to do this, make sure the puller is very tight (pulling for all its worth) then apply bits of heat to the gear - not too long though, then try to turn the main bolt on the puller - repeat. Hope this helps - getting the gear off is most often the biggest challenge on this job.