I have a '06 w 127k miles. Never serviced transmission shame on me. Anywho when shifting from D to OD around 1k rpm or 45 to 50 mph it shakes the whole truck violently. If I accelerate it stops or if I turn OD off it stops. I've heard a lot of people say if the tranny hasn't been serviced before 100k mile don't service it, I don't know. The plugs were changed about 80k miles. Other than that the truck runs like a top. Suggestions are greatly appreciated. BTW it is a super crew FX4 5.4 FFV if it matters

 

That's more likely plugs and/or coils. However, DO go get a full tranny fluid exchange. If it fails, it was going to fail anyway.

 

Don't care what that "lot of people" say. Change the fluid.

D

 

Had the exact same thing with my truck except it was a 2001 4.6L and it was just a COP which is the same case for your truck.

As far as the tranny fluid, mine was never changed either. I probably wouldn't do a complete fluid change with a machine but that is just me. What I do plan on doing is just doing a pan drop and replacing the fluid. Yes I know the new fluid get contaminated but I plan on doing it every 3 months or so till the liquid becomes cleaner little by little without "shocking" the tranny system. I'm not a professional but that is just what I am doing. If anything I know "glc" is alot more knowledgeable than me on these vehicles.

When I did the pan drop the fluid still looked good and red for some reason. The yellow stopper was still in there and the truck has about 120k miles on it. Ever since changing the COP I never had a problem with the truck.

 

What is "COP" coil on plug? Would the check engine light not come on if it were misfiring a lot? Also do I leave the yellow stopper out when I put the pan back on?

 

Yes, a COP is coil on plug. It won't trip the CEL until it's almost dead. Leave the yellow stopper out. However, I recommend a COMPLETE fluid exchange - dropping the pan only gets 5 quarts out, the tranny holds 14 quarts. Take it to a shop with an exchange machine, the pan doesn't have to come down.

 

Have the same problem and feared it was the torque converter, a pretty expensive fix. My Ford garage diagnosed 2 bad COP and the the converter was good to go. Once those come in and they change the plugs they say the problem is fixed. My 06 Lariat only has 72K on it.

 

Agree coils I would do full tune up coils,plugs,Fuel filter, air filter or cleaning on aftermarket, clean MAF & throttle body and reset KAM, I would just drop the pan on trans and change filter and fluid that comes out with it if you want by a plug kit and drain again in a few oil changes, here's my problem with complete flushes depends where you get it done but basically they should be boiling hot like stall test hot and I have put a tranny in recently that was flushed at a lube shop and it wasn't the first and won't be the last.