Oil/fluid recommendations for a coach that's been sitting

[Bob Horner]

Originally Posted by DFB052686

looking to change all fluids on the new Bird. has maintenance history, always used 15w40, from oil change places, looks like Dexron III(or whatever stock is, no notation) on trans.

*92k miles now (300hp 3208/ZF)*

- looking for recommendations between straight 30wt OR 40wt plus STP (this seems to be the magical combo?)

- should I swap the trans over to synthetic ASAP? and if so, stick to name brand fluid? does the ZF use transynd?

the rare bird has been sitting for a decade off/on. tires and records support this. oil pressure is above 60psi on gauge when cold at idle. when warmed up a bit the number drops to about 20-30. when full operating temp at idle the gauge will read ZERO. if I get the rpm's up even say 50rpm. the gauge jumps back to a reading of 20-30 or so... and sometimes the gauge "flickers" up a bit... regardless of the reading. could this be a dirty pressure sensor? failed oil pump? crocodiles in the sump?

I am also contemplating running some Dexron III in with the oil for a few miles before I do the oil/filter change. is that a poor choice?

Today I started my gen for the first time, the gauge was flickering up and down around 20psi, I realized the wire was little loose on the end of the sensor, I crimped it down with some pliers to tighten it up, the pressure went to over 40 and no bouncing of the needle.

[kunzelj]

I would not trust the gauge either. I had my oil pressure tested at a shop with a proper gauge and it was different (higher at idle, and about the same at higher RPM). There is an oil pressure sender connected to the oil cooler. I will be replacing this to see if it makes the gauge more accurate.

15/40 Delo or Rotella in the engine, zero additives.

Shell Spirax S6 A295 in the transmission, though Shell also makes a similar product that is certified with ZF... it's the same oil with a different certification I suspect. It's all "TranSynd". The ZF is such a costly transmission, I figure the oil is worth it.