I have started feeling what a lot of people call the overdrive shudders that happen around 45-50 mph. I have read and continue to read quiet a bit about it. It seems like it got bad pretty much all at once. It seems that it is hard to tell the difference between overdrive transmission problems and actual engine miss and I have read that engine miss can actually cause the transmission to shudder. It looks like it has the coils replaced not long ago and I wonder if they are low quality coils. I can take it out of overdrive and it stops the hard jerking but it seems like I can feel some cylinders missing, not a dead miss but like they are not firing to full capacity. I need some help diagnosing this problem and determining where the problem is or maybe in both places. My scanner is several years old and was not a real expensive one at the time I bought it and it does not show any codes with the trans or an engine missfire. I think that will be one of my first steps to upgrade. Any suggestions on a good scanner that is still affordable, if they make such a thing. As always, any help and advise will be greatly appreciated. Thank You in advance.

 

An affordable scanner that will read all codes and data is Forscan. You can download it free at www.forscan.org. Their page shows how to select an adaptor to plug into the OBDII port.

 

do you have a flashing CEL when the shudder is occurring?

 

Not that I have noticed. I believe I would have noticed it if it was but I'll check a little more thorough and let you know.

 

At low rpms under a load, cylinder pressures are higher, harder to fire a mix and in OD the TC is locked, so you both increase chances of misfires and increase the chances of feeling it as a driver. It ain't a transmission shudder that you feel .... it's the miss you feel.

If the wrong transmission fluid is in the transmission or just really old, then you might have a shudder, but if a code shows a miss, it's not likely a trans shudder.

 

I drove it some more this morning and as for the CEL, mine is on all the time for another problem, the cylinder head temperature sensor, therefore it wouldn't flash would it?

 

tbear853, I like your thinking. That makes sense. My daughter has an Expedition that they have driven probably 5+ years that does the exact same thing and a couple shops have told them it was the transmission therefore I just assumed that is my problem and a lot of the videos I have watched they call it some kind of transmission problem but then fix it with coil packs, spark plugs or something like that. Hard for me to understand until you explained it like you did. I'm looking for someone local that can do a complete fluid change instead of just dropping the pan and I have to get me a more up to date code scanner, looking at downloading the forscan that Mark Kovalsky mentioned above. I like everything about it except for the extended license deal but I can live with that.

 

You probably don't need the extended license. If your just going to read codes, the license isn't necessary.

 

Do you use the OBDLINK EX adapter. I will use it with a Windows 7 computer. Does the forscan program have to have an internet connection to operate or is it a stand alone program?

 

It does not need internet to operate.

 

Obviously you'll need a connection to download the program, update, and enter your activation code for a license -- if applicable.

Current tariffs make sending money to Russia problematic but there's a stupid easy workaround so no one need grumble. There's a guy who will buy a license for you and send you the codes. He's all over the Forscan FB forums but he started his own site (just to streamline things) as AKM software. I used him and he's legit. Typically these things are scams but he's the real deal. Don't take my word for it -- the mods on the Forscan FB forum will confirm. No affiliation and not my site. If you look at my history on FTE you'll see it's unlikely I'm somehow in cahoots with some guy to scam you of a few bucks for a Forscan license (I'm not, to be clear)

Good luck

 

My shudder end up being 2 plugs, tried to get coughed out, and hung on the cooler it was outside, the less likely it would shudder, it has 109kmi on it, now 3 plug changes.