2006 Ford F-150 new vibration after trans replacement

Hello, I have recently swapped out a transmission in my driveway. When I finished bolting everything together and started it up to test it, There is a pretty bad vibration, it happens in park neutral. It’s not quite as bad when driving but does vibrate a little when shifting. ( is an automatic ) I’ve checked pretty much everything I can, all the bolts are tight and everything is put back together exactly how it was before the swap. Wondering what all could be causing the vibrations and where to look to troubleshoot.

Did you change the torque convertor?

Did you change the flexplate (flywheel)?

What engine is in your F150?

What I am getting at here is an imbalance in the torque convertor, the flexplate or the combination. Maybe unbolt the torque convertor and rotate it to the next bolt and re-attach. Maybe that will clean up the vibration

It’s the 5.4L V8 I did not change the flywheel. The transmission I took out did not have reverse, So I swapped it out of another truck that had a working transmission. I used the same torque converter from the transmission I pulled out of the other truck, ( I never removed it from the transmission ) if it is the torque converter. Wouldn’t I have to remove the transmission again to rotate it? It doesnt seem like it would be possible to do that unless you unbolt the bell housing from the engine and pull the tranny back… Trying to avoid that if at all possible.

Well I partially answered my own question… There is no way to rotate the torque converter whilst the transmission is bolted to the engine, So If it is what you are thinking, I will have to drop it again… That seems like a lot of work… Wouldn’t I potentially have to drop the transmission and then re-attach potentially 4 times in order to fix that? Is there anything else I should potentially check into that could be a probable cause before I do dig into something like that? Additionally thank you for your help and advice, to you and anyone who may have some input on this matter :blush:

With the driveshaft out did you happen to inspect the U-joints to make sure they operate smoothly with no slack in them?

What about driveshaft orientation; meaning the yoke should attach back to the rear axle in the same position that it was removed?

Front U-joints can be a problem and I’d certainly consider that before dropping the transmission back out.

IF this turns out to be a U-joint issue I would recommend spending the extra bucks and replacing them with Spicers.

Yes I marked both drive shafts put them in exactly as they came out, and all the U joints seemed to be in pretty good shape. And the vibrations are the worst at idle and seem to fade on acceleration. The only time it vibrates on the road is when you let off the gas and then go to accelerate, at least in the higher gears 40 mph + lower gears seem pretty smooth, and driving is pretty smooth all around as long as you are keeping on the gas. Its Pretty shakey at stop lights also and is worst at idle…

I’m leaning twords the balance issue mentioned, or maybe a warped flywheel or bad motor mount. Really unsure though, I know the engine itself seems pretty shakey and the exaust. The motor mounts seem to look okay, But I’m unsure on how to tell for sure. It doesnt jump too bad when I shift it into gears but also hard to tell as I have to check from cab as At the current moment I only have myself…

How did you bolt the torque converter up to the flex plate? Usually the bottom of the bell house allows you access the attaching bolts. What Mustangman is suggesting is unbolt those bolts, rotate the flex plate 30 or so degrees holding the torque converter steadyuntil the next available attachment point is present and then install all the bolts in the flex plate. Keep doing this until you get the most vibration free location.

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So, The torque converter has 4 bolts to attach it to the flywheel. You have to turn the crank on front of engine and bolt them on from the port you just mentioned. I followed a guide when installing it, it didnt mention anything about balancing, it just said to line up bolts and slide transmission on so that’s what I did. When I fastened the bolts I went around once loosely ( hand tighten ) while pushing the converter through with a pry bar ( there is about a 1/4" of play ) After I went around hand tight I went back over and snugged them up whilst skipping a bolt to torque them snug in a cross pattern.

What I was getting from mustang was to unbolt and turn torque converter and move the bolts to a different location on flywheel one turn. That isnt possible though unless you pull transmission back from engine. There isnt enough clearance from the studs on the converter to the flywheel to rotate it to change where they go through the flywheel… If that makes sense anyway, hard to describe. I did unbolt it today and try with no luck, Also made sure to bolt it back on as even I could just in case I wasn’t cautious enough the first time.

With studs it won’t be possible to re-position the torque converter, most torque converters are held with bolts. There is usually one mount on the torque converter that is off by 10 degrees of position to the others that allows the torque converter to be installed in only one position.

It sounds like you have a rough idle, an engine performance problem. If it were a balance problem it would get worse as the engine speed increases. Check for vacuum lines that may have come loose and the air cleaner intake tube to the throttle body for leaks.


No, This Torque converter can definitely be installed in 4 possible positions, I didn’t think too much of it as the directions I was following didn’t mention anything about balancing or having it in an exact position. I do know there is an issue with a lean condition code that popped up so maybe I will check into the engine side of things more, but I wouldn’t think that would cause quite so much vibration. Also concerned about the vibrations it had about 40+ mph when you let of the gas a bit then go back on it it will stutter some also. That and the fact it didnt vibrate that much before tranny was swapped makes me think something related to swap…

Just an update here, I decided to check into engine side of things further and found some new information. Getting a recurring trouble code for a misfire on cylinder 2. I’m thinking my problem lies there and not with the transmission itself. I’m now worried it may be wiring harness related, as that is the only thing I can think of related to tranny swap that might have any effect on that. And I’m really unsure on how to test to see if that is the case. Anyone have any further insight on this? Any ideas on what might help to trouble shoot? Where I should look first?

It is doubtful that it is wiring harness related. It is likely bad plugs or coil. Swap the coil on the cylinder with misfire to a different spot. See if the misfire code moves.

I think the 05-07 fords had a 2 piece plug design. These can have their own issues when removing. If you research the issue you will find the stories.

How many miles on truck and have the plugs ever been changed?

Honestly dont know for sure, it only has about 180k miles on it but im guessing they have never been replaced. I never touched the truck prior to the transmission swap and have zero mechanical history on it, other then the previous owner was a construction company.

And yes, Doing a plug inspection on it now, At least attempting to. Not a fan of the 2 peice plug design and have no idea how you are even supposed to change the plugs on this…

Just like any other plug. The issue is if it breaks off you are going to say a few cuss words and tow it to a shop if you don’t have the special tool. Unplug the coil wire, remove the coil, remove the plug. plugs are 9/16 socket as I recall. I didn’t have the spark plug socket for that size so I had to fish the plugs out using a short piece of hose.

Many people fear this process from the horror stories and they delay until they cannot delay any more. I just did the plugs on my 08 v10. I was lucky that I had the newer plug design that don’t break off. I bought the tool used on craigslist for $20 to have just in case.

Yes it was the bend in the hole that tripped me up, Was getting worried about getting a socket stuck in there so stopped what I was doing and decided to research it. And then found the horror stories and think I’m going to save the removal of the plug as a last ditch effort…

Keep in mind if they have ever been replaced in the last decade, it will likely be the replacement 1 piece plugs that don’t break.


Unfortunately, if op buys motorcraft plugs, the new ones will be identical to the old ones . . . in other words, the weak design that’s prone to breaking

If you want the one-piece design, you have to buy the special Champion brand plugs, which aren’t any cheaper than the factory plugs, last time I looked. And even worse than that, many auto parts stores don’t carry those special Champion plugs

It is possible to remove all plugs without breaking, but it involves huge amounts of decent penetrant, working the plugs back and forth, a lot of patience, and common sense

if somebody can’t wrap their brain around that, they need to have the Lisle brand broken spark plug removal tool handy