you can try regular upkeep like changing the fluid but it may be to late. It could also be electronic and not mechanical related. Might need a rebuild or to buy another transmission. Be VERY careful of who you have rebuild it if you go that route.
it is hard to tell from just that descriptiion, if its got high miles its probably just its time to be rebuilt.
2003 Cobra Vert (Redfire) #3938 of 5082 @ 05/27/2003
472rwhp/493rwtq -Modification List
- Dyno Sheet
2012 Mustang 3.7L M6 (Kona Blue)
2011 Ford Edge Sport (Red Metallic)