Hello everyone! We own a 1998 Honda Civic EX, automatic transmission. We recently replaced the radiator, and ever since the transmission has been acting a little funny. I don't know that the two are related, just that this problem popped up around the same time as our radiator replacement. It still shifts gears pretty alright, but when it does, it's a little more rough than it used to be. Kinda like it has to jump into gear. Any suggestions on what our problem might be?

 

The radiator also has a line in & out to cool the transmission oil. Make sure they hook it up correctly when the shop replaced the radiator.

 

When the radiator is usually replaced, you have to disconnect the hoses that are for the transmission oil. The radiator cools the transmission oil as well. So I'm thinking(or guessing) when you or someone else replaced the radiator that they didn't replace the transmission oil that was loss.
Start your Civic and wait till it gets to operating temp(when the radaitor fan comes on is when it reaches operating temp). Turn the car off & check the transmission fluid level.

And...check for leaks :-)