steering gets tough when trying to park at low speeds on my 2000 Buick LeSabre

The hydraulic power steering system of this vehicle also has a variable power assist feature, using the vehicle speed sensor to work with the variable effort steering actuator to vary steering wheel effort. Either the base hydraulic system or the variable assist system may have issues. It will require hands on testing to figure out what's going on. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops