Transmission studded

[Peirson S]

hello all. I’m hoping someone can help me out here.
Beginning of this week my 2005 expedition 3v 5.4l, transmission began to prematurely lockup in 2nd and 3rd gear. Great. Took it to my local tranny shop (aaction transmission) and they diagnosed it and said it needs to be rebuilt, $1690. I got the work done picked up the same day, we’ll the same night I’m driving on the highway and now In 4th gear at 60-70mph I get a slight studder, and my acceleration gives out for a couple seconds. I have to let off the throttle and reapply and it evens out. It doesn’t do it every time either it’s very random. I was having this issue before the rebuild also. Also I now have a engine code for a p0430 (cat below threshold bank 2) if someone can give me some kind of insight it would be appreciated. Thank you.

Just to add I just replaced all plugs and coils before the transmission crapped out.

 

[Habbibie]

That code is for cat converter, after driving it for more than 20 minutes at night I want you to look under the truck... is the cats glowing red by any chance?

 

[Peirson S]

I looked last night thinking of the same thing but no there not glowing hot. I also checked to make sure they tightened all the exhaust bolts and made sure there wasn’t an exhaust leak

 

[gixer2000]

Misfires are often confused with trans issues and could also be connected to the P0430. I'd pick up a scanner that has mode 6 so you can see any misfire in real time. I use Bluedriver obd2 scanner and it works well

 

[metaldrgn]

You could also just pull all your COPs and look for moisture since you already replaced them. Moisture in the boots can cause misfires which will cause what you are describing. All you have to do is use a compressor, blow it out and reinstall everything. Misfires happen more under load as it takes more energy to jump the gap so if there is an alternative easier path for it to take it will.