2017 Ford C-max energi transmission clunk/thump with light acceleration or light tap on brake before stop.

[Marcusk]

I have a 2017 Ford C-max with 102k, and for the last 10 thousand miles I hear a light clunk sound/ thump from the front end drivers side when doing light acceleration or sometimes right before the car comes to a complete stop. The clunk is more noticeable in warmer weather. The dealer has checked the whole front suspension and motor and transmission mounts and said everything seems okay. At first he could not make the sound until I drove the car with him. It is more noticeable if you put car in reverse and stop and then put car in drive and lightly accelerate. You also here it sometimes when going in reverse and stopping. The intensity of the sound can be louder at times. The dealer replaced the drive axel which made less vibration in the car but the clunk is still there. I brought it back to the dealer again and they told me there transmission expert says the clunk is normal for the C-max. I never heard the noise for over 3/4 of my miles so I don't believe they are telling me the truth. I have brand new rotors and brakes all around. Any opinions or suggestions would be appreciated. Marc

[nogoodbum]

I'd look more closely at front suspension components, sway bar bushings, end links, or strut mounts for examples. Look thru the suspension part of this forum for more & better ideas. Sadly dealers today are lost without an OBD code to tell them what is wrong, for the most part. You may be able to pin down the noise with an extra set of ears & eyes during a bounce test, again MAY. Thanks for the read.

[Hafro Samurai]

Finally figured it was time to hop on here and and talk to people who actually drive these things.

I straight up have been dealing with suspension issues since shortly after moving to the Portland area from Seattle in July. My 2013 was smooth and quiet until maybe the end of August and then started what I can only describe as an endless temper tantrum hah. Road noise was more noticeable along with the ever increasing bounce party. I soon realized that three places I took it too about the symptoms all said the typical "everything looks fine and in great condition," "Oh, I couldn't get it to make the sound you're talking about, it's probably because it's a hybrid," etc. Well, not month after a Ford specialty shop did a $250ish inspection with a focus on the P0304 code for intermittent misfire in cylinder 4 and suspension (from the research I had been doing) and a good sized unmarked pothole, my right shock threw in the towel and was bottoming out on the slightest of bumps. I had self diagnosed that with the bounce test.

Fast forward to now......having no experience doing suspension work or much engine work either (let alone on a modern and hybrid car), I have replaced the spark plugs, ignition coils, 2 injectors, both shocks, rear and front sway bar links, both front lower control arms, and both outer tie rods. So here's the kicker.....my car is just about to hit 42,000 miles. No joke! I really don't drive like the crazy a$$holes who always go WOT and brake hard. I do however it up with people's found luggage and deliver it for different airlines. On top some bad roads at times. I have acquired the clunk that you're talking about and it surfaced after I had replaced a top hat(?) Bolt with a smaller flanged bolt rather than the wider washer resulting in having to fight a stripped bolt for hours only to lose the nut out of the underside. I said screw it and have the 2 bolts holding it poorly as I am certain they are loose. If you do the work yourself it's not too bad getting access to them but please save yourself the headache and note, mark, and/take pictures of how your wiper arms are placed while in the service position as when you plug in the harness they will need to be at that spot when you start it next. Also try not to drive it much with the wiper motor disconnected, it threw me some codes for the low beams and also made the car run rough.

Found this out after replacing some parts too. If you do your own wrenching, hand tighten any suspension fasteners with it lifted or on stands, but make sure you load the suspension either on ramps or with a jack before torquing them. 

I realize you may have already figured out your issue, but I just wanted to let you know that you are NOT crazy and that you ARE hearing the clunks. I about lost it the last time they said nothing was wrong and they didn't find any codes thrown.... would've been really nice if someone had faced similar problems haha. I've been learning a metric butt ton by doing the work myself and even been dabbling with the electrical canbus side of things. To you or anyone else who's trying to save money and gain that life xp, I'd be glad to share my knowledge, help or at least make an attempt!

Oh, and wish me luck as I said to hell with OEM suspension components, replacing what I can with Moog parts and Godspeed coilovers arrived the other day. Figured adjustable damping for those dirt/gravel, mile long driveways would be noooice!