I had my transmission fluid flushed and ever since then, when the car switches gears, it feels like it slams into gear (more than it used to before). It doesn't happen all the time, or between every gear shift, but it feels much more noticeable lately. Is it possible that the mechanic used a low grade fluid replacement? Or is it just me being more sensitive to it?
Sometimes, on older and/or high mileage transmissions, a fluid flush can be detrimental. The old fluid (which is full of friction material from the transmission clutches) is all that is holding the transmission together. However, this may not be the case with your vehicle. There is a TSB 08-07-30-002A for your Buick which states harsh shifting may be caused by problem with the valve body. Since the valve body is used to direct fluid flow to the transmission, it’s possible that your transmission flush exacerbated this problem.
Other potential cause for your symptoms include a low fluid level (if the shop didn’t add the correct amount), faulty accumulator, incorrect line pressure, and more. The list or potential causes is quite lengthy, so I suggest you have a trained professional inspect your vehicle firsthand to pinpoint your shifting problem.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing