Loud clunk and lurch when coasting after acceleration and braking.

[FireFighterHill]

I have a 2014 C-Max Energi SEL with 89k miles. I am located in North Florida near Jacksonville. I bought it recently from a county auction. It was previously used as a Probation Officers car. The Service history was up to date and it looked great inside and out. Well after driving it in stop and go traffic it started doing this thing where it almost feels like the electric motor is loading up the drive train and then instantly unloading. This makes a very loud clunk or bang noise and causes the car to lurch or shift as if something with alot of mass or inertia just moved or shifted. It typically does this when you are coasting after you just accelerated from a stop or if you go from acceleration to hard braking, like you do in stop and go traffic. It doesn't do it all the time, but its fairly consistent to the point I can almost predict when it will happen. The only way I've found to prevent it, is to shift the car into neutral and then back into drive once I'm stopped or need to accelerate again.

 

Ive replaced both the top passenger side motor mount, as well as the bottom torque mount. This had little to no affect on the issue.

I have not serviced the transmission fluid as I have an appointment with the Dealer for this Friday and wanted the dealer to diagnose the problem under the 8 year 100,000 mile hybrid warranty.

 

Has anyone had this same issue?

Would this be covered under the TSB for noise and problems with the Transfer shaft and HF35 transmission bearings?

Has anyone had trouble getting Ford or the Dealer to honor the extended Hybrid warranty?

If so what steps did you take to get them to honor the extended hybrid component warranty?

[FireFighterHill]

Well the dealer has had the car twice now. Total time its been at the dealer is over a month. They still cant figure out the issue. They claim they cant get it to replicate the issue. I'm pretty sure that's because they've only been taking it on short trips around town. I drive about 50 miles each way to work starting on highway and ending in city traffic. After the first time they said it was the CV joints. So I replaced both sides along with strut assemblies, spindles, lower control arms, tie rod ends, rotors and pads. The issue is still there.

 

I did note that when I drained the transmission I pulled out about 1.5-2 quarts less than what I put back in when I refilled the transmission. To make sure I had the proper level in, I put the driver side tire back on, parked on my level flat driveway, and let any excess fluid leak out until it stopped and was even with the bottom of the fill hole on the side of the transmission.

 

Also of note, is while the transmission fluid wasn't bright red anymore, it did not smell burnt and had no metal in it or fine metallic particles that i could see. I even let it sit in a clear bowl to see if anything would settle to the bottom. About the only difference ive noticed since doing the maintenance is that it seems to not clunk as loud or lurch as hard. I think this can be attributed to fresh transmission fluid, or maybe the new tight CV Joints.

 

My issue is now, the dealer claims there's nothing to fix, I paid them 300 dollars to diagnose the issue and they recommended an unnecessary repair, and my only other option is to take it to another dealer and pay another diagnostic fee, and hope they figure it out. Or I guess, keep driving it until some catastrophic happens. The problem with keep driving it is, there's less than 10k miles left on the warranty.

[SnowStorm]

Here's a couple of wild guesses:

• There is some kind of breakaway "clutch" between the ICE and the transmission.  Read about it here.  If it were faulty, it might be causing the problem if it slips (when it shouldn't).  You have to remove the ICE/transmission unit from the car and split them apart to get to it but you don't have to open the transmission.
• There is some software issue that hasn't been updated.
• Are you using any engine braking ( L on the gearshift or the hill descent button on the side of the gearshift).  I doubt you would in FL but I still think it was an engine braking transition that damaged my transmission.  There was an awful clunk/lurch after a long period of engine braking.  My guess is that there was a software bug that didn't handle the transition properly.