Differential Unit problems of the 2012 Subaru Outback

: the transmission stared acting up randomly in early February of 2017. The transmission would slam into gear while shifting from 2nd to 3rd gear, accompanied with a huge bang while the whole car would rattle for a second or so. A very scary and unsafe scenario because it felt like you were being hit from behind by another car. Afterward, the car would run normally for few days before it repeats. So I took my car to rallysport engineering in costa mesa, CA on April 10 who confirmed my complaint and replaced the valve cover of the transmission. The problem appears to be solved until a month later. Around June, a new transmission shifting problem was appearing and gradually getting worse. When tried to accelerate slowly while coasting between 3rd to 5th gear, the car would shudder noticeably and hesitate for a second or two before got going. This is a very scary and unsafe situation if you need to accelerate to avoid obstacles on highway or surface street. In July, I took the car back to rallysport engineering for repair. It confirmed the shuddering problem but it could not identify the cause so it referred me to Subaru orange coast (oc) because it has access to technical support from a dedicated Subaru factory �super-tech�. Subaru oc kept my car for four days before returning to me. It could not identify my car problem, and instead, the mechanic staff told me I have differential and wheel bearing problems. I need to fix these two problems ($1012) before he can zero in on the transmission shuddering problem. I told the mechanic my car symptom is very repeatable and he should be able to duplicate and identify the problem without requiring me spending big money upfront. He was unable to help because there was no stored diagnostic code to guide him! I complained and shared information with Subaru of America but no avail.