5 years seems a little early. Maybe just do a front end now but even that may not be necessary. The best thing to do is take an oil sample and see what shows up in the oil. If there is no tin in the oil then chances are your bearings are fine. Leave it sealed unless there is a real reason to mess with it at this point. Once the hours get really up there then you could consider doing it for exploratory reasons.
You can find the tol in the IOM manual use 19XL teardown book. I go off of oil sample depending on type of load chiller runs at and Carriers wonderful design with no rear motor bearing your low speed is ussally done also. Take it down and put new bearings in regasket it.
before teardown , you need to check the following:
take oil sample of the unit and see what is the oil condition
how many operation hours of the unit (very important)
perform a vibration analisys (very important)
before open the machine will be better make a prediagnostic