Hello all, I have a 93 Bronco XLT, 160K miles 5.8 L. Tranny was replaced at the dealer at 50,000 (previous owner)

Last week, the Check Engine Light come on and it starts shifting REALLY hard. Slamming. Especially bad Park to Drive, but even 1st-2nd is a jolt. No prior warning, no missed shifts, no slips, absolutely no indication that the trans was failing, just wham, one day.

I do have an oil leak, maybe valve covers or rear main, that blows oil back onto my undercarriage and trans on the highway. Is there any chance this is some sort of fouled sensor causing bad shift signals? Anything I could look at before I drop $800 on a trans or, more likely, sell my Bronco ?

Any thoughts would be great

Thanks,

Chad