Driveline vibration 2007 Ford Fusion AWD

Have someone check your driveline universal joints and make sure that the driveline is secured to the differential.

Something in the drive line is loose or has lost a bolt etc and it takes a certain amount of torque to get it vibrating, hence it appears above 35. Closely inspec the driveline to find it.

Have the u joints checked on the drive shaft that goes from the front diff to the transfer case one or more my be seized or loose .

You have problems with the driveline angles.There are TSB that the dealer has to go through.This is common for Fords

The pinion bearing has escessive preload. When this happens there excessive vibration.On 4x4 the front and the rear drive shaft has to rotate at the same speed. you are mainly locking up, the pinion is not moving freely

VIBRATION - DRIVELINE RESONANCE/VIBRATIONBETWEEN 1400 AND 2000 RPM WITH CONVERTER
Clutch ENGAGED DURING MEDIUM TO HEAVY
THROTTLE CONDITIONS - VEHICLES WITH 7.3L DI
TURBO ENGINE AND TRANSMISSION BUILT PRIOR
TO 11/13/95 (5L13)
^ TRANSMISSION - E40D - DRIVELINERESONANCE/VIBRATION BETWEEN 1400 AND 2000
RPM WITH CONVERTER
Clutch ENGAGED
DURING MEDIUM TO HEAVY THROTTLE
CONDITIONS - VEHICLES WITH 7.3L DI TURBO
ENGINE AND TRANSMISSION BUILT PRIOR TO
11/13/95 (5L13)

FORD:
1995-1996 E-350, F-250 CREW CAB, F-350 CREW CAB
Article 96-26-21 is being republished in its entirety as part of a consolidated 7.3L diagnostic aid booklet.
ISSUE
Some vehicles with transmissions built prior to 11/13/95 (5L13) may exhibit a driveline resonance/vibration between 1400 and 2000 RPM with the torque convertor engaged. This may be caused by the torque converter.
ACTION
Prior to torque converter replacement, refer to the following Service Procedure for details to verify conditions.
SERVICE PROCEDURE
1. Verify the resonance/vibration does not occur in neutral and is most noticeable between 1400 and 2000 RPM with the converter clutch engaged during medium to heavy throttle conditions. Also watch for the vibration to diminish at engine speeds lower than 1400 and higher than 2000 RPM. If the concern meets all of these conditions and the transmission has a built date prior to 11/13/95 (5L13), replace the torque converter. Refer to the appropriate Service Manual for removal and installation procedures.
2. If the vibration concerns do not meet the conditions, check for non-factory installed items that could affect driveline and verify proper installation. Also refer to the appropriate Service Manual, Section 05-00 for diagnosis and testing.

I'am supprised you didn't expect this to happen ,when you raised it!

Balance the rear driveshaft ,and adjust your trans and rear pinion angles.

How many miles on your Durango? This could be a failing U joint on either driveshaft. Could also be a ties out of balance or going bad.

Since the vibration goes away when coasting, I am voting for a driveline issue.

first i wound check for mud build up on the inside of the wheels

Sounds like a bad u-joint or if its a 4x4 a bad cv-joint.