believe torque converter shudder

What do you mean torque convertor is not locking up? What symptoms are you getting now? You said the shuddering went away. It takes time for the fluid to make its way through pump/ torque convertor. Two quarts low would definitely cause problems. Pressure is dependent on proper level in trans. Imagine trying to pump oil throughout your motor with only 4 quarts vs 6. It would be struggling!

Sent from my N9131 using Tapatalk

when I first started having problems I noticed that when I stepped/tapped brake there was no rpm increase as if torque converter was not unlocking. When I drove it the other night I was paying close attention to rpm's and was only seeing 3 rpm drops as speed was increased. Made me think converter isn't unlocking because it isn't locking in first place? Also wife drove yesterday said vibration/shudder was still there?

The toughest problem your going to run into is finding a shop that is capable/willing to diagnose your problem. Their are 2 torque convertor solenoids that possibly could be at fault. Theirs probably a test, but at $30.00 each, id just swap in new ones. I think you stated theirs no noises coming from transmission, if a torque convertor doesn't lock up, you'd have slipping, overheating of transmission, along with the 30-50 mph shuddering. Your going to need to hunt your area for a real transmission specialist. One that can diagnose your problem. Ask a lot of questions. Another option, is to install both of the torque converters solenoids yourself. Between parts and some of your time its under $100.00. Your fluid is brand new, if not burnt, reuse most of it. That's what I'd do for now.

Sent from my N9131 using Tapatalk

Thanks Moose you have been a great help. I've seen a torque converter clutch solenoid would you know the name of the other I can go to rock auto and look? There is a noticeable rpm increase and decrease as the converter lock and unlocks on my 97 f150 that I am not seeing on the expedition

It's called a pulse width modulation solenoid. It looks like the first one is a bolt on item. Maybe someone here that has more trans knowledge can chime in how to further test or if we're barking up the wrong tree! This is out of my comfort zone. Me personally have always saved open heart surgery for last resort! If its an outside replacement part and a possibility, I'd try it, what are you out, maybe $50.00 or less. Hell we spend more than that drinking or watching a ball game!

Sent from my N9131 using Tapatalk

I agree I figure if I'm not spending more than a couple of payments a year I'm ahead of the game! however if it's the tranny I have to do some serious pondering!

Well that's why we and I always recommend testing first. Sometimes you've got to say what the hey, and swap out a part. In some cases you can return the part. It's not a total science! Especially transmission issues, that's why most shops wimp out and sell you a complete transmission, that way they know their going to get paid, parts/labor. Same goes for engine issues, they could spend hours troubleshooting, and be wrong, or sell you a reman motor, and know it's going to work. Sadly it's the world we live in.

Sent from my N9131 using Tapatalk

Well I decide to take drive shaft out and check u joints. They felt good while in but I had a jeep that felt good that would bind at tranny at 45 mph. Anyways the seemed to be alright tranny one was loose but not sloppy feeling. Decided to change them since it was out. Had a spicer tranny yoke which started the u joint nightmare as the ones called for is to short for that end and a project when you install them and they're to short. Reinstalled drive shaft went on 20 mile drive (city/ hwy) got no vibration. Hopefully this is it!! Have to figure torque converter lock up another time.

I Believe the converter is locking up , it is subtle compared to my f150. I did see movement in the rpms as it turned on and off. Think. I'm going to change front diff fluid since all others are done and install the front drive shaft.

Hey Moose. Ever get an answer if this fixed the 50-55mph shudder? I have ruled out Universal joint on my 06EB but fixed some wonky vibrations. Tightening plugs fixed my (everyone thinks it's a normal Ford 'tick' sound especially in drivethroughs). Removing/replacing catalytic converters fixed a whole BUNCH of things (175K miles). My fuel economy went up 80 miles per tank!! Incredible difference. But I still have that f-king shudder when overdrive is deciding if it wants to drop down.. I was just going to buy the clutch solenoid but as I read more, it could, feasibly be the PWM. So she shifts PERFECT, except from the overdrive to fourth/third. Shifts perfect INTO overdrive. Any idea which solenoid controls the shift OUT of overdrive? Thanks!! Love this Triton the more I fix it. It's going in my 2003 Mustang GT when its 4.6 explodes.