As the saga continues: I recently changed the transmission fluid and filter per directions. The old fluid was nearly a dark burgundy color. Everything went great until I started driving the car. Smooth going up the gears but at about 10 mph slowing it gives a good thump-a-thump that wasn't there previously. I've tried searching but can't find anything relevant. Did I do something when I changed the fluid/filter? Any thoughts would be of great help.

 

Did you happen to check the level before you drained the old fluid? Was it still full? And when you filled it up did you start the engine after topping it off, run it through the gears and then proceed to top it off again with the engine still running? Have you checked the fluid with the motor running and at operating temp since the drain and fill to make sure it's still full?

 

Yes, I followed all of what you mention. It has been several days since drain/refill so will check it again as soon as possible. What would cause the thump-a-thump in down shifting? Over-fill/under-Fill? Previous neglect???

 

You didn't do anything like leave a dirty rag draped over the drive shaft that is whacking the frame at 10MPH did you?

 

I would get under there ASAP to double check the fill level and have a good look around. Of all my searching on tranny issues the past several weeks, I did not come across one thread in regard to your individual situation. If everything checks out, the only thing you can do is pull the pan again and see where you went wrong, since this problem was not there prior to you molesting it.

 

i know it been asked before, but you are checking the tranny with the truck running

 

Yes, I checked the tranny with the truck running and, no, I didn't leave a rug, etc., to bang against the frame. Wish it was that simple. I'll pull everything again and see what;s what as soon as possible. Last time I checked the fluid was a bit frothy. Is that normal?

 

Just a shot in the dark, If you pull the pan, check to make sure the o-rings are in the filter, one between the filter and valve body, and one between the filter and pickup tube. The fluid being frothy, could be air getting sucked up. Frothy may be normal, but I don't think so.

 

Just me thinking out loud... If the filter isn't sealed where it mounts on the sump (o-ring) or the pick up tube attaches to the filter (o-ring), could the sump be drawing in air along with the fluid causing the frothiness?

edit: Lol Joe
I hadn't refreshed the page when I wrote my response after dinner to see you had the same thought.

 

I only thought of this, because I just changed mine. I got the filter that Advance Auto said would fit mine, and it was the wrong one. I went to Autozone and they had the right one. It came with the o-ring for the filter to valve body, but not the one to the pick-up tube. I reused the old one for that and everything works great. I did park on an incline to fill and check(and remembered to chock the wheels).
Went for a ride and came back and rechecked(was not frothy).