My 2006 expedition has 200K miles. At approximately 195K miles I started getting a slight thumping or shuddering feel between driving 40-65 mph. As a background, at approximately 100K miles I had the same problem and I took it do the dealer for the recommended tune-up and the problem was solved with new spark plugs, etc. I figured it was the same problem so this time around I took it to my local mechanic and he didn't receive any codes of a spark plug misfire, etc. and said the problem was torque converter shudder and referred me to a transmission specialist. The trans shop agreed and told me I needed to rebuild the trans. Not knowing any better, or getting a second opinion, I agreed to have the trans rebuilt. Within driving 40 miles, the same problem resurfaced. The trans shop offered to install a shift-kit. Within driving 10 miles of the install, the problem resurfaced. I'm wondering if my transmission was bad at all or simply misdiagnosed. The good news is I have a rebuilt transmission, but the bad news is I still have a problem. Doing my own diagnosis, I realized that the thumping/shuddering goes away when I disengage the O/D button. Any suggestions on what is really wrong with my truck? I bought it brand new and I'd like to keep it a little longer. The car drives fine otherwise.

 

Welcome to the site...

Converter shudder is/was fairly common on higher mileage trans, and even reared it's ugly head on low mileage units prior to the fluid upgrade to Mercon V. Back in the day before the fluid upgrade products like Shudder Guard were used to help correct the condition. Worked pretty well. That said, on the mileage mentioned, when was the last time ignition related parts were replaced/serviced?

Ignition related misfires like you mentioned can mask or be similar sensation to a shudder. If you cancel out OD and the problem completely disappears, it very well could be a converter or lockup issue.

Sometimes conditions 'have to' be met (ignition misfire) meaning about the same throttle angle, load, RPM, to produce the misfire as it would as if it were in OD. You might try finding a long grade, cancel OD, and try and keep RPM's and throttle to about where you would normally experience the shudder. Basically,, to see if 'you' can reproduce the shudder but in a lower gear..

 

I don't have the receipts, but my best guess is that I had a few spark plugs replaced in 2012/2013 after the initial replacement at 100K in 2010. The torque converter was supposedly replaced during the rebuild. Could it still be bad? I can't seem to reproduce the problem when the OD is canceled at lower speeds or any speed for that matter. My next stop is the Ford Dealership. They apparently have a onboard diagnostic tool that can run codes while driving the vehicle. I just feel like I wasted $2k on a rebuild that I didn't need.

 

My 2007 Expedition EL has the exact same issue. It has about 100K miles. I haven't taken it to a shop. I assumed it was some sensor in the tranny is defective. Turning off O/D seems to help, just like yours.

Did you ever resolve the issue? What was the answer?

 

Chuck.....A few months in maybe late March early April, I took it to another mechanic who suggested that I keep driving it until the check engine like comes on. Otherwise, he would be guessing on what the problem really was. So I did. Last Friday 5/10, the check engine light came on and I took it in and the code reader indicated a problem with the coil and plug in cylinder 4. They were both replaced and the problem is now gone. Cost me $280 from a local mechanic. In retrospect, I may have acted prematurely fearing that my transmission was failing and didn't get a second opinion before paying for the rebuild. The Ford maintenance schedule calls for a transmission fluid flush at 150K miles. When I reached that mileage everyone told me not to get it done and that it would ruin my transmission completely at that high mileage, so I didn't. In the end, all I probably needed was a spark plug. Do not go to a transmission shop. Take it to your local trusted mechanic and see what he says. Hopefully, he'll say just drive it until the engine diagnostic system tells you exactly what's wrong with it. Hope this helps!

 

Transmission service strategy is a 'fluid exchange', not a flush as in the past. The benefits of an exchange are like changing the engines oil. Heat and fluid shear degrade the lube, and much better to do the regular mileage intervals...

 

Thanks for the info. I also suspected it might just be a mis-fire. Kinda odd that it doesn't throw a code for misfire. :-(

I think Ford recommends replacing the plugs after 100K miles. That was the interval on my F150. I may replace the plugs and see if that fixes the problem. If it doesn't I will look at the coils next.