When I hit 55mph and above , I notice a slight vibration in my drivetrain. If I let off the gas, say at 65 and let it coast, once I come down to 50 mph, the truck rides smooth, vibration goes away. It`s not really all that bad but it`s noticable. What`s the problem? The dealer had it 2 times for the issue. 1st time they said tires needed to be rebalanced so they took care of that. Well, no go. 2nd time they said tires are choppy due to lack of rotation (thx to previous owner) thats the reason for the vibration. Well, no go. I replaced the tires and its not as bad but it`s still there. Also on these cold mornings, when I drive down the street it feels like I have a flat spot in my rear tires until the drivetrain warms up then it`s fine. I think the problem is in the trans. What about the rest of you? What do you think? Help. Thanks.

 

I have the same problem and I've had a Balance, Rotation, and Alignment done this week...

I notice the "wobble" around 58mph and starts getting rough around 60mph... But only while I'm accelerating. It's not really bad when I'm cruising.

I think it may be the U-joint.

 

Could be drive line imbalance. Try to index the drive shaft in 90 degree increments to the rear axle. Or put a band clamp on the drive shaft and rotate in 90 degree increments until it gets better, then fine tune.

 

what type of tires did you replace with?

also how much air is in your tires?

 

Well they "said" they checked all of that as well and everything is fine. I call BS on everything they say at this point. I may have to take it to a different dealer now and hopefully get somewhere with this.

Also, this is kinda funny. I had a rear axle seal replaced cause of a leak and seen on the invoice that thay replaced the crankshaft sensor for some reason I don`t know why. (warranty) So I asked the service writer why they replaced the crankshaft sensor and he said, "some diff fluid got on it and messed it up." WHAT? I said. Thats nowhere close to the rear diff!!! Then told him where the sensor was located. He couldn`t answer me after that. Apparently he has no idea WTF he`s talking about. Not good.

 

Yokohama Geolandar A/T-S tires. Haven`t checked the tire pressure but i`m sure that has nothing to do with my problem especially since I had the problem before the tires.

 

did it change any when you replaced the tires?

 

Yeah, it`s not as bad as it was but it`s still there and it`s really starting to **** me off.

 

I feel your pain. My old Lightning had issues similar to yours, and I took it to 2 different alignment shops, which both said everything was fine and the tires were balanced correctly. Well, I ended up using the alignment rack in my auto shop class and it was WAY off. I don't know why they would just flat out lie, but maybe try taking it somewhere else and see what they say?

 

My 2003 Edge auto 3.0 does exactly what you descibe. Mine has 38K well cared for miles. I just put the new Goodyear Fortera Silent Armour tires on which are a HUGE improvement over the OEM tires. My alignment is dead on!! I believe the issue is the ring and pinion. Mine makes a whining noise between 40-55 mph also.
If it were the drive shaft I don't think warmed up or cold would make a difference.