The 109S of my aquaintance does this on occasions, albeit temporarily on start up or when large power changes are made. The engine oil temperatures on that airframe usually sit about 12 C apart with the hot engine showing slightly less oil pressure.
If an engine oil cooler thermo valve malfunctions you will know about it very quickly (seen that whilst IMC with 6 pax, diverted single engine).
The transmission pressure always sits right at the top of the green, occasionally into the yellow at 51-52 psi. Having questioned our maintenance agency they tell me "it's normal".