transmission help please.

well the trans in my 89 xj went out. i just put a lift on it and slapped some 32s on it. just wondering if there is a difference between the 87-90 xj and the 91-01 h.o. xj trannys. basically if i have to get a new trans i want to get the best one. i called a couple of trans shops and they told me that my xj has the toyota 340f trans in it. and a few guys on mjr told me to get the x2 trans. but none of the tans shops have ever heard of the x2. i just want to get some straight answers. or direct me to someone who specializes in jeep transmissions. ive already dumped 4000 into this thing last mont and just want to get this damn trans fixed. someone help me out thanks.