So my friends xj8 came up with "transmission failure". Carr has done 75k miles. When I drive it now, I do not get the message but do get wild flare on some shifts 2-3 or 3-4. I checked fluid level and found it was about 2 QTS low. I happen to know that PO changed fluid at home but may not have filled to level correctly. We still get transmission slips with correct fluid level.

When driving, manually, each gear seems to drive OK.

I am thinking that there may be sticky or bad solenoids, or the mechtronic module transmission seal may be leaking.

Am looking for suggestions on diagnosis.
Should I look to change solenoids, and fluid and seal, or is it a bigger issue?

 

Hey neighbor! I'd start with changing the fluid and filter, then re flash the TCM. The fluid fill is an issue, hopefully there's no long term damage. There are also known issues with the sleeve in the transmission that leaks and may have introduced contaminants. I'm not sure what year the car with the issue is but I think the issue was consistent with most X350s.