I've had a similar vibration problem. It felt like if I was driving 100 yards on smooth asphalt and then 100 yards on cobblestone roads. This was occurring when in gear only. Like in a downhill slope even in gear if I get off the accelerator it wasn't doing it. then when slope ends and straight away I step on the gas, it was again on, off, on, off and so on.
It was found to be the problem with "torque converter"... It has been replaced under warranty thankfully I caught it just before 60,000 mile warranty limit and now silky smooth no matter where and how I am driving.

 

Yes I'm having the same issue, and have taken my van to Ford three times. They can't figure it out. So a friend of mine ended up purchasing at 2017 also. Before he purchased it I told him about my issue with mine.. His is doing the same thing.. This has to be a recall..

Dig a little deeper.

Driveshaft Drone Noise Survey

Do you experience the highway-speed hum, vibration or droning noise in your Transit? I just went through the vibration and humming noise thread collecting bits of data looking for a pattern. I have found just enough to see hints of something, but no smoking guns yet, I need more data. If you...

www.fordtransitusaforum.com

What's needed to trigger a recall..

 

Yes I'm having the same issue, and have taken my van to Ford three times. They can't figure it out. So a friend of mine ended up purchasing at 2017 also. Before he purchased it I told him about my issue with mine.. His is doing the same thing.. This has to be a recall..

 

Dig a little deeper.

Driveshaft Drone Noise Survey

Do you experience the highway-speed hum, vibration or droning noise in your Transit? I just went through the vibration and humming noise thread collecting bits of data looking for a pattern. I have found just enough to see hints of something, but no smoking guns yet, I need more data. If you...

www.fordtransitusaforum.com

 

@dmhtransportinc try a transmission fluid flush. Has worked for some and far cheaper than a new TC.

 

I had a similar vibration in the drivetrain of my 2017 Transit 250 from 35-45 and 55-65. A local mechanic diagnosed it as torque converter shudder and told me to put a tube of Lubegard Instant Shudder Fixx in it or to have the transmission power flushed. I put the two ounce tube of Shudder Fixx in and it has not vibrated or shuddered since then. Amazing stuff!

 

I believe it! Lucas transmission fluid has got many transmission working normally again for me as well. I am going to give this a whirl.