High Mileage Transmission Service

[dallasmef]

I bought a high mileage 1997 Explorer and took it in for maintenance and requested a transmission (T) servicing from the dealer. He advised me that if I didn't know the history on its' servicing that I could be making a mistake with the (T) if it was shifting OK. He explained that the gears and the old oil develop a working relationship and that new fluid may be too "slick" for the internal parts to work properly.......and it may not go in gear. This sounds (to me) like the (T) has adapted to a higher viscosity concentration relative to new oil.

Is it possible to service the (T) and replace the oil with a heavier weight oil to compensate for the lower viscosity of new oil by measuring the viscosity the exisiting (T) oil and replace it with new oil having the same properties.... even if it is NOT the manufacturers factory recommended blend.