shudders when I make hard right or left turns?

It's understandable to be concerned about the situation, especially if you're unsure about the diagnosis and the cost of the repairs. Here are a few points to consider:

Shuddering during hard turns: Shuddering during hard turns can be caused by various issues, including problems with the drivetrain, suspension, or wheel alignment. While a broken transmission component could potentially cause such symptoms, it's important to explore other possibilities as well.

Struts replacement: If you recently had the struts replaced and the problem persisted, it suggests that the issue might not be related to the struts themselves. This raises the possibility that the original diagnosis may have been incorrect.

Metal shavings in transmission fluid: Metal shavings in the transmission fluid can be a cause for concern, as it may indicate internal transmission damage. However, it's difficult to determine the extent of the damage and the exact component(s) affected without further inspection.

Second opinion: Getting a second opinion from another qualified mechanic is generally a good idea, especially for expensive repairs or when you have doubts about the diagnosis. It can provide you with more confidence in the assessment and help you make an informed decision.

Price estimation: Without knowing the specific details of the required repairs and the labor costs in your area, it's challenging to determine whether the quoted price is appropriate. However, major transmission repairs can indeed be expensive, so it's crucial to obtain multiple estimates to compare and ensure a fair price.