Yeah, I'm sorry I don't have better news, but this type of problem usually has to deal with the friction plates or the band and drum system breaking, but it could also be that a valve body is plugged and a flush could fix it(that's rare) . The only other thing I've seen cause this is letting the tranny fluid run almost dry, usually less than a quart left in the tranny, most tranny's use between 9 and 13 quarts, and this usually has damaged the tranny. If you haven't, you might check the fluid level, and for any leaks. Yeah, I'm sorry I don't have better news, but this type of problem usually has to deal with the friction plates or the band and drum system breaking, but it could also be that a valve body is plugged and a flush could fix it(that's rare) . The only other thing I've seen cause this is letting the tranny fluid run almost dry, usually less than a quart left in the tranny, most tranny's use between 9 and 13 quarts, and this usually has damaged the tranny. If you haven't, you might check the fluid level, and for any leaks.