i have had a 2000 suburban i gave to my kid,has 300k on it,had an 05 sub with 280k,have an 03 express van with over 300k,and currently have an 02 sub with 225k and none of em that i can tell have ever had a gear changed.but my 03 express is slowly leaking p.s. fluid from a hose.have to give it some fluid about every 2 months or so.too lazy to change it as it doesn't get many miles anymore.