2008 Ford Expedition stuttering while driving at 40-50 mph

[fuzzmanmatt]

Ha! I actually am having this exact issue, decided to see what info I could find.
It's like a surging, most noticable around 1700 rpm, it dips and then catches up.

My first thought was TCC solenoid, since the issue goes away when overdrive is turned off. It COULD be an ignition issue, but I've got a reman engine with new coils, so I'm leaning towards transmission. I put a Motorcraft MAF in last summer after getting codes for that. I'm not opposed to trying the friction modifier, honestly. I just don't want to drop the pan in this snowy weather.

Sorry for resurrecting an old thread, but I can at least say I didn't start it!

 

[amoreno]

Sorry if I'm posting this too late:

I brought my '08 Expedition (180k miles) to Brian Laskowski's shop (https://www.youtube.com/@FordTechMakuloco) for a rumble strip sensation when going up hill at around 30mhp/1800-2000 rpm. This is what Brian said:

"I did duplicate the rumble strip sensation and sadly it is coming from the torque converter. For this concern I would definitely perform a fluid and filter service with an extended drain and retest from there along with a friction modifier additive before we just condemn the torque converter completely. Transmission fluid and filter service with additive runs $210"

Brian changed the ATF, and there was no need for the friction modifier additive. I have put 20k miles on it, and the transmission is as smooth as possible, no more rumble strip sensation.

If this is the same thing you've been experiencing, you know what to do now.

 

[Brent Harward]

Update on FoMoCo Friction Modifier for 2013 Expy stutter trubs listed above. I've now got 7000 miles on the modifier and NO stuttering. The hard part is sucking out 4oz of tranny juice while car running (19mm). HOT~ See YouTube for tranny oil change to see how to do this. I'm very happy with this fix. In fact, I find it hard to believe it worked!

 

[Brent Harward]

More update to using FoMoCo Friction Modifier. While pulling a trailer the stuttering returned about 40 mph and 55-60 mph. I got about 8500 miles out of the friction modifier, but, sadly it has slightly returned. I fear the torque converter is the real problem. I've done plugs/C.O's and injectors. Maybe fuel filter? Ugh. Read the complete tranny oil change and will try that next. No other issues with the Expy. Runs & drives great until that damned stuttering kicks in. Will return post oil change.

 

[GaryH]

I had the same problem intermittently for a while, but it seems to have cleared up. It was more of a shudder than a stutter. Hasn't done it in the last year. Not saying that was the problem, but I did replace all the coils and plugs last year.

 

[JExpedition07]

If you have a 2007-2008 with the 6R75 the solution I found is shudder guard (product attached). I replaced the torque converter with a brand new Ford unit in my 2007 back in 2020. Also swapped ALL new Mercon SP into the system. After another 1.5 years it started to shutter slightly again. Put this stuff in and it stopped shuddering and drove and shifted perfectly fine. I have not asked my buddy who bought the truck last February for an update but last I knew it was still driving around fine this spring. The 6R75 torque converter lockup clutch material is a bit weak, this helps it immensely to lockup and prolong the life of your lockup clutch material by stopping the slippage that is wearing it out.