We want to change the oil in our IH 885 tractor transmission, it says in the manual to use Case Hytran [MS1209 spec] and have seen some other oils like Mobil 428 that claim to do a good enough job. But case say that it doesn't have some kind of necessary additive specific for the transmission. So does anyone know if there are any substitiutes and the likely effects of using them and if this additive is so important. It seems that this spec. they quote of M<S1209 only applies to their machines - what is so special about it? The dealer rep. is totally brainwashed with the idea that nothing will do the job that hytran does is he giving us BS or not?