98 explorer tranny issues

I have a 98 Ford Exploder Sport with 148k miles on it. I am starting to have transmission issues and was wondering if anyone has seen a similiar issue and wether or not it may be repairable without replacing the entire tranny.

A couple of times this month I have noticed a loud clunkiing when going into reverse eventually this led to a whirring sound and an inability to go into reverse that would pass over a couple of minutes and then engage. As of right now the whirring sound is happening when I am going down the express way and I take my foot of the gas and coast or when I go into reverse which does not engage at all.

I am not sure if I even want to put a used tranny or a rebuilt into the vehicle. Also curious about what this may end up costing me.

Did you find the solution as my ford does the exact same thing and I'm thinking it is the toqure converter soleinoide. This is because I had the transmission and the transfer case stripped down and the toqure converter replaced. This worked for around 3 months then it happened again, so now I'm thinking that the soleinoide is sticking as it was clean before and also that the mechanic may have put the wrong grade of oil in the transmission because I read somewhere that these boxes need some special type of oil.
If anyone can tell me the type of oil needed and how to remove the soleinoide so I can clean it up I think I might be back on the road. I can't afford to send it back again. 97 explorer
Thanks wato

Mercon 5 fluid is the best.(besides aftermarket)

If you want to throw a part at it then I would suggest a new valvebody. These valvebodys go out and no one can even diagnose them very well, except by taking an "educated" guess. The valvebody will have the solenoids on it and bonded gaskets, which is much better than original.