I have an '06 250 Super Duty, 6.0L w/auto trans. The dealer keeps telling me my shutter/vibration/droning problem is a driveline issue. This is felt when the truck is under load or accelerating and starts at 2100 rpm, and is horrible right before the first shift when I stomp the pedal and rpm gets to 3k pulling a 9K trailer. The 3000 rpm shudder goes away when the truck is in 4 wheel drive and when I'm not pulling the trailer. They have replaced the pinion and carrier bearings, checked the drive shaft u-joints twice(both times they said u-joints are fine), lubed the driveshaft slip joint and rebalanced all 4 tires. After all this, $900, still no resolve. They put a vibration analyzer on and the tech said it was driveline still and that the driveline angles would be the next step. I bought the carrier bearing shims per the TSB for shudder prob at an earlier date, followed the install procedure n after all 3 shims were installed, still the same shudder/vibration/droning. What I can't figure is why my shudder/vibration/droning prob started as soon as I picked up the truck after they only changed the front diff fluid, did a trans flush and replace the dust seals on the front axle? They hadn't even messed with the rear of the truck at that point. Does anyone know if this could all be happening if the incorrect fluid type(mercon instead of the SP) was used in the flush?

 

It is possible they used Mercon/Dextron III (Now Mercon V) instead of the speced Mercon SP. Mercon SP is a lower viscocity fluid than the perviously mentioned Mercon which I'm sure would have ill effects on a transmissions specing SP.

You could try giving Blackstone Labs a call and ask them if they could tell you what type of ATF you have in your truck currently if you send them an ATF sample.

 

I have called Blackstone Labs and they can/will test the fluid. My question is mainly, would the wrong fluid cause all these probs? is what I described symptoms of the wrong fluid? The problems I described didn't exist till they worked on the front end and changed the trans and diff fluid. And if it is mechanical whats going wrong? Is the trans NOT considered part of the driveline?

 

I will PM the link to this thread to Mark K., he knows tons more about the subject than I do.

 

I don't think the wrong fluid can cause shudder like you're seeing. It can cause the shift solenoids to stick, but that will cause it to not shift properly.

 

Thank you dkf and Mark. Mark, I see you are a "Former Ford auto trans engineer." So if the wrong fluid can't then what could possibly be the cause? I have read about TCM programming/flash. The FICM was done on the truck shortly before all this started but they said the TCM gets flashed at the same time. Any of those related? I got a second opinion from a trans shop but their first thought was u-joint. Dealer says the u-joints are fine. A buddy said, w/out any suggestion from me, torque converter, which was my first thought. This gremlin magically appeared when the truck had the initial work done and everyday I drive the truck the vibration/shudder/drone is getting progressively worse!

 

If it is the trans shuddering it means a clutch is slipping. If a clutch has been slipping for more than a mile or two, the fluid will be burned black. Is it?

 

No, the fluid is still bright red and no longer sweet smelling , its a more sour smell now. Fluid has 1500 miles on it. What about torque converter failure? Again thanks your your help and insight

 

Since the fluid has changed from new in 1500 miles, I think it needs to be changed with the right fluid.

 

Is your truck lifted?