If kicking down @ 70mph, tach hits 5500 RPMS and car does not accell. Also make a screeching noise. Need to let off on the gas before it shifts back down again..

Sounds like your transmission needs maintenance. Has this tranny ever had the filter and or fluid changed every 30,000 miles? If not, you may want to consider doing it. The longer it goes, the more damage its doing.

I bought the car with 150,000 miles on it.. Never had an issue until recently and it now has 200+ miles. I am not sure if the tranny has ever been serviced or not. I think it was a camper tow behind type vehicle due to the tow hookups in the front looking very used. The check engine light is also on and seems to be idling low... Not sure if those 2 things would have anything to do with each other or not. Thanks much for the info though!

I bought the car with 150,000 miles on it.. Never had an issue until recently and it now has 200+ miles. I am not sure if the tranny has ever been serviced or not. I think it was a camper tow behind type vehicle due to the tow hookups in the front looking very used. The check engine light is also on and seems to be idling low... Not sure if those 2 things would have anything to do with each other or not. Thanks much for the info though!

. Attach a code reader to the data link connector under the dash.

. Drop and clean the pan, change the filter, and refill with Mercon V ATF, if possible.