How do you mean? GAM have never had anything to do with toll maint wise. I dont think they've ever touched the metro's garretts let alone anything else.
The expansion into using the Do228s for freight was brought about by the poor standard of Jetcrafts Metro fleet. Toll bought Jetcraft out and restructured the runs and aircraft operations as a method to "bid" out the 228s. As a lot of Cadbury employees are finding out, Toll are very good at destroying competition by simply introducing alternatives and pushing down prices and delaying contracts until they're able to buy them out a "reasonable" price.
All fell flat on its face when they realised how tightly strung bank running is and opted not to go ahead with that take over.