Hello guys..(its about 98 XJR with 120k miles) Last summer I stuck on 635, after driving few miles in almost dead traffic i realize that my tranny taking high rpm to shift from 1st to 2nd..this is my weekend car so i came home and park it.. today i changed engine oil and drive it, and it drives perfectly fine...

Should i let it ride or do something to fix it.??

Any advise?? thanks