Car is old and has lots of miles, 378k

I changed the valve cover as it was leaking and after putting it back together took it for a drive and the transmission started slipping.

Never had an issue prior to the valve cover repair.

Changed the fluid and filter ran smooth for a few miles then started slipping again.

Is there anything that taking off the valve cover would have done to cause this? Something i missed hooking back up maybe?

Sorry not the biggest car person in the world.

Thanks

 

At 378K, if that is the original AT in the car, you're about 200k mi overdue for AT tranny slippage.

On these ATs the input shaft nut works its way loose and the valvebodies become problematic.

The fact that you are OBD I sucks unless you have a scan tool that can read the TCM in the car

Is the SES light on?

 

Re check to make sure all vacuum lines are reconnected

 

No lights on, original drivetrain. I bought the car for $600 at 196k and have only put a water pump and brakes on the thing.

Have read some of the valve body issues in here, was just curious since it started immediately after swapping out the valve cover if I just missed something on reassembly as it ran perfect when i took it apart.

 

i will pop my hood in the morning and see what's where and post back