Can you put up a picture as well as the UT number. The people that took over the John Deere parts are Ryobi Australia but they are not very helpfull with information.
You could also try Husqvarna as they took over Poulan and the 1625 model could be the same gear (it has a metal drive tooth centre with plastic teeth gear).
Regards,
Bruce
Please do not PM me asking for support. Post on the forums as it helps all members not just the individual.