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2009 Lincoln MKZ - Vibrates and rumbles

In the last 5 or 6 weeks we have had the car suddenly start vibrating and shaking as though we were driving over rumble strips. It feels like the car is “stumbling”! Then it stops after about 1 minute or less and is fine for days after. The paving is most often perfectly smooth and we are typically at speeds of 20-50 mph, although is some cases we were pulling out of a turn or slowing for a turn, so speed was changing. It’s only happened six or seven times in as many weeks, so of course it’s hard for a mechanic to experience it. Nothing else seems to be different and our tires were all replaced in August and balanced and aligned at that time. We have all wheel drive and automatic transmission and are retirees driving relatively little in the suburbs. Any Ideas what it could be??

Not without you telling us more information, Gretchen. Specifically, is there a check engine light glowing yellow on the dash when this happens… or all the time? Or some other light appearing when this happens?

What you have described are the classic symptoms of problems with the transmission’s Torque Converter Lockup mechanism. Have you faithfully changed the trans fluid 3 or 4 times so far?

If not, my recommendation is to take it to an independent trans shop in your area for a fluid and filter change and a diagnostic. Don’t go to Lee Myles, Cottman, Mr. Transmission, or–God forbid–AAMCO, where you will be told that you need a transmission overhaul, when merely servicing your neglected transmission is probably all that is necessary.

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VCD Driver, thanks for your reply! Just got a call from our Lincoln Dealer who says they drove it and were able to experience the problem. They are convinced that it is a bad U-joint seizing up and want to replace the drive shaft for just under $1k. Does that sound right to you? Also, to MustangMan, no lights on the dash come on at all.
Many thanks for the help! Gretchen

My advice to the OP is to take her 11 year old car to an independent mechanic (not a chain-run shop such as Midas, Meineke, Monro, Sears, Pep Boys, Firestone, or AAMCO) for evaluation of the U-joint(s). Unless there is something truly unique about this Lincoln model, a bad U-joint can be replaced without a need to replace the entire drive shaft. And, if–as I strongly suspect–the U-joint(s) on this model can be replaced w/o replacing the entire driveshaft, then the bill will be just a small fraction of what the dealership wants to charge you.

Telling a customer that they must replace the entire drive shaft because of one or more bad U-joints is simply a case of padding the bill unnecessarily, IMHO, and this is just one more example of why one doesn’t need to continue to patronize the dealership after the warranty expires.

Sincere good luck with the resolution of the problem, and please report back to us on the outcome!

Edited in order to add the following:
While your vehicle is in the shop, I strongly suggest that you have the trans fluid and filter changed if this wasn’t done during the past 3 yrs/30k miles. This could help to prevent a VERY expensive transmission failure in the future.

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Just to end the story after all the kind advice, I went to an independent local garage for second opinion. He looked up the U joint and found for that model the drive shaft and U joint come together - you can’t just get them separately. I let the dealer go ahead and the repair seems to be good (just picked it up) but I’m going back to my new-found local guy to get the transmission serviced. (We just moved from out of state so it took a while to find him and by that time the dealer was already doing other repairs.) But I have a question about the transmission flushes. I’ve read so many articles referring to them as “wallet flushes” and saying that they are even dangerous to the car because cheap fluid is used and can damage the transmission. My owners manual does call for a transmission flush but not until 150,000 miles! Since I’m at 130,000 now I guess I’m due but why the bad hype about it?

If somebody uses the wrong fluid, of course they can damage the transmission.
If somebody doesn’t know what he is doing, he can damage the transmission.
Hopefully your mechanic knows what he is doing, and will not use the wrong fluid.

The main reason why trans fluid changes get a bad rap is because most people don’t do them every 3 yrs/30k miles, and only resort to them as a Hail Mary Pass when trans problems surface. Then, when the transmission fails shortly afterward, they blame it on that one long-delayed trans service, when the real reason is that the trans wasn’t serviced regularly, as it should have been.

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