Dynapack dyno

I have a question for everyone. I just bought a used Dynapack dyno.that's been in use for ten years without ever having its hydraulic oil changed. I want to change the hydraulic oil, but what type should I buy? Thank you.

An older Dynapack manual had this info:

Wheel Units

 Oil replacement is dependent on the hours of work the Dynapack has carried out:

o If under Low Power High Usage then we recommend changing the Hydraulic Oil at least every 4 years (48 months) Replace with Caltex HDZ 46 Hydraulic Oil.

o If under High Power Heavy Usage then we recommend changing the Hydraulic Oil at least every 2 years (24 months) Replace with Caltex HDZ 46 Hydraulic Oil.

 Using an air-gun blow any dirt/dust from inside the pump head on each wheel unit this will remove any build up around the optic eye. Do not clean the optic eye with harsh abrasives.

 DO NOT apply grease inside the spline shaft on the wheel units – this will cause a build up of grease on the optic eye. Use LOCTITE 777 (Nickel Anti seize) and apply sparingly with a toothbrush or similar to coat the shaft and grooves, this will prevent buildup on the optic eye.

 Spanner check the rose joint on the top of the buoyancy spring. Do not over tighten.

Oil Change

 You will need to use CALTEX Rando HDZ 46. 205L (44 Gallon) Drum.

 You will need approximately 80 litres for each pod. Depending what happens with oil levels inside the components within your pods, the approximate total will be 160 litres. You will not need to drain the whole system.

Okay, thank you! Do you have a link to the full user manual?

Dynapack should be able to send you one. Here are the two copies I have:

Thank you so much！