Wanted to see if you guys could help me out here, recently my truck starting shifting extremely hard into all gears especially reverse, trans is good just did a flush last month and all fluids are up to date. I replaced the VSS sensor yesterday and that seemed to immediately fix the issue, now today driving 15 miles to work I have the same exact hard shift all over again. Any help would be appreciated!

 

Is the check engine light on?

 

No check engine light, now throwing code 628 Excessive Clutch Slippage which is crazy to me because the trans was just flushed 2 months ago with no issues or anything

 

What does flushing the trans have to do with a code 628? Are you saying that the new fluid should have prevented the mechanical failure that caused it to set a code 628?

Most likely the apply piston in your torque converter has developed a crack. That's leaking pressure so that the converter slips when it should be fully locked. The amount of slip required to set this code is small enough that you won't feel it.