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Allow me to preface this by saying this is not my truck, it belongs to my father but I use it almost as often as he does, and only I have noticed this problem. It started a few months ago, at around 55 mph it would shudder gently, every few seconds. At 50 it would stop, and at 60 it would stop. The problem gradually worsened and now it does it at 55, 60, 65, and 70. It also will sometimes do it at 45 and 50, but not nearly as often. The shuddering is also becoming stronger. The longer you maintain the speed, the more intensely and the more frequently it shudders, eventually becoming one constant shake. A deviation in speed or revs of even 2 mph or 200 rpm will make it stop. It generally happens when you have maintained one of the above speeds for over a minute, and only once the RPMs have settled to about 1500-1750. This truck runs and drives like brand new in every other way, including when accelerating and decelerating. All of the above leads me to suspect the overdrive. On the other hand, a trusted friend of mine who rode in the truck and experienced the shaking believes that the torque converter is going out. He said that he had to replace one on his old F-150 because it was having similar symptoms of only shaking when the overdrive engaged. I’d like more opinions though, so I thank you for any and all help you can provide.
Some stuff you should probably know:
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Thought I should update this old thread. When it came down to it, the truck still technically belongs to my dad and he didn’t want me tearing the engine apart, so it’s sitting at our local mechanic’s shop right now. It should be done by the end of today and I’ll let you guys know if the misfiring from the plenum gasket was, in fact, making it shake.
Well the gasket was destroyed, and the truck runs great now, no more pinging, stumbling or episodes of the exhaust smelling like aerosol-ized cancer. The heater core still makes noise and the guy had to bleed it to do the procedure so there’s another leak somewhere. The heater works though so for now that’s on the back burner.
HOWEVER, it still shakes under the same conditions as before. The drive shaft isn’t dented or warped and the tires are worn, but worn evenly. I think we’re back to square one.
Thanks again though to everyone who pointed me in the direction of the plenum gasket as it was in very dire need of repair.
Well the gasket was destroyed, and the truck runs great now, no more pinging, stumbling or episodes of the exhaust smelling like aerosol-ized cancer. The heater core still makes noise and the guy had to bleed it to do the procedure so there’s another leak somewhere. The heater works though so for now that’s on the back burner.
HOWEVER, it still shakes under the same conditions as before. The drive shaft isn’t dented or warped and the tires are worn, but worn evenly. I think we’re back to square one.
Thanks again though to everyone who pointed me in the direction of the plenum gasket as it was in very dire need of repair.
At least a problem was fixed and eliminated from the list of possible causes. I still feel that there is a driveline issue somewhere but it seems that’s going to be difficult to find based on your description.
At least a problem was fixed and eliminated from the list of possible causes. I still feel that there is a driveline issue somewhere but it seems that’s going to be difficult to find based on your description.
I think your friend my be right ,What might be happening is when the transmission goes into lock up,the clutch in the torque converter may be chattering when applied causing the shutter your feeling.
I think your friend my be right ,What might be happening is when the transmission goes into lock up,the clutch in the torque converter may be chattering when applied causing the shutter your feeling.
In another thread it was suggested that someone with the same symptoms disable their TCC solenoid to keep it from locking up and verify that as a cause. In my truck, it isn’t easily accessible, or I’d try it. If that is the cause, I can’t ever see having the money to fix it so I guess I should get used to it. Worst case scenario, the clutch loses complete ability to lock and I run a few hundred more RPMs on the highway right?
It was just brought to my attention that a fluctuating TPS signal could make the TCC lock/unlock rapidly and give me the exact same symptoms. Time to buy a scanner with live data…
In another thread it was suggested that someone with the same symptoms disable their TCC solenoid to keep it from locking up and verify that as a cause. In my truck, it isn’t easily accessible, or I’d try it. If that is the cause, I can’t ever see having the money to fix it so I guess I should get used to it. Worst case scenario, the clutch loses complete ability to lock and I run a few hundred more RPMs on the highway right?
It was just brought to my attention that a fluctuating TPS signal could make the TCC lock/unlock rapidly and give me the exact same symptoms. Time to buy a scanner with live data…
I just read something in alldata about these trucks doing something like this…
Let me see if i can find it.
I just read something in alldata about these trucks doing something like this…
Let me see if i can find it.
[quote=”EricTheCarGuy” post=37175]At least a problem was fixed and eliminated from the list of possible causes. I still feel that there is a driveline issue somewhere but it seems that’s going to be difficult to find based on your description.[/quote]
I really dont see how this would be a drive line issue???
A drive line has alote of stress and torque put on it – Most when accling. It is true that the drive line flexs/twist under heavy loads (Verry little but it is there) That being said -I Would think if the drive line was (WARPED OR OUT OF BALANCE) the issue would be more noticeable when accling or such with centrifugal force working agents it even more.
Maybe a ujoint issue or yoke issue but I would think you would hear that.
[quote=”EricTheCarGuy” post=37175]At least a problem was fixed and eliminated from the list of possible causes. I still feel that there is a driveline issue somewhere but it seems that’s going to be difficult to find based on your description.[/quote]
I really dont see how this would be a drive line issue???
A drive line has alote of stress and torque put on it – Most when accling. It is true that the drive line flexs/twist under heavy loads (Verry little but it is there) That being said -I Would think if the drive line was (WARPED OR OUT OF BALANCE) the issue would be more noticeable when accling or such with centrifugal force working agents it even more.
Maybe a ujoint issue or yoke issue but I would think you would hear that.
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