Certainly don't know a lot about jacks, but I will tell you that most all have the same bolt pattern, especially if you stay with the same weight rating. To remove, first jack up the front of the trailer, let it down on blocks or a jackstand, remove the three bolts at the top holding the jack in place, disconnect the power wire, and remove the jack. Installation is of course, the reverse. Don't be shocked at the price of a new one, as they are rather pricey. A friend of mine did recently replace his jack with one that he got for a good price at Harbour Freight, but I don't know the price, or the quality of the jack.
Do you know what is wrong with your jack? Suppose it's repairable?
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