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It sounds like when you drive over rumble strips, or the grooves on the berm of the highway. It will do this for 1-2 seconds. It will happen 2-3 times a minute, or may go for 5 minutes without doing it. Any speed over 30 mph. Four new tires and the air is up to snuff. Definitely not balance either. Trans? Anyone ever experience anything like this. I appreciate any help. 94 f-150 std. cab, 2wd 302 auto
Did this problem exist before the new tires?? If no, check the lug nuts. If yes, check all of the mounting points, engine,trans,body, etc. also look at ball joints, and suspension components.good luck
Dave
Thanks guys. I don't know if it occured before the new tires. I just recently bought the truck and these tires were on it. I have'nt had the A/C on, and it happens with the Overdrive off or on. Can't really say if I feel it in the steering wheel or not. It seems to be the whole truck shuttering - just like driving over rumble strips at high speed.
It's also throwing a code for the EGR valve, but I would be surprised if these conditions were related.
Does the vibration/noise occur when the truck is idling?? I know that you said that it only occurs over 30MPH-but have you actually verified that it will not occur during idling??
check the carrier bearing on the driveshaft , if ur model has one, its a big u shaped thing on the middle of the rear driveshaft, it supports the driveshaft.
Check your drive shaft U-joints, the needle bearings could be coming apart and getting unbalanced. I had a old Bronco that had the rumble strip sound and thats what it was.
Thanks all. I,ve looked for anything out of balance and all u-joints seem to be tight. It does'nt seem to be a balance thing, as I can be running along smooth as silk on the highway (or in town for that matter) for 5 or 6 miles, then I get the vibration for just a second or two. It may repeat 2 or 3 times a minute, or may not do it again for a few miles. As I said it sounds and feels just like running over rumble strips, a high frequency vibration.
Try this:
Go to Ford and buy a small bottle of Motorcraft Additive Friction Modifier for the rear end, put this in the transmission.
This has helped a lot of members.
If this does not work then flush the transmission, drain the torque converter, change the filter and refill with Mercon V (5) ATF.
This also seems to fix it for a lot of the posters including me.
One other note, while you are in there if the transmission (I am guessing you have a 4R70W transmission) has not been updated your problem could be a bad piston. Clean the bore with scotch bright and replace the piston with a F7AZ-7F251-AA piston from ford.
This piston can also cause this.
This applies if it happens at the 1-2 shift.
Last resort there is an updated torque converter that can also fix it.
The new updated torque converter does not have a drain plug.
This applies if it happens at about 43 MPH.
If the truck does this out of gear setting still as you slowly rev the engine then disregard what I wrote above.
Thanks, I was just starting to suspect the torque converter, as I can feel it locking and unlocking at steady speed. The locking/unlocking and the vibration both seem to occur at any speed over about 30mph. And both events happen when I am at a fairly steady speed. It is a 4R70W, and the tranny itself seems to be tight. Is there any way to confirm this diagnosis? A way to keep it from trying to lock up maybe? I'll try the additive and then the flushing, but I'd sure hate to replace the TC without knowing for sure that it is the problem.
Here is my Transmission story.
The TC made after April 2002 is an improved TC and you can ID it as the TC does not have a drain plug.
I also had a vibration in my 95 truck with a 4R70W when I bough it.
I went as far as building a Transmission tester so I could look at all of the signals as I drove and it has switches on it so that I could cut in and out signals to the transmission as I drove.
So now I could see when the computer shifted gears and turned the clutch on and off.
I could tell right off the bat that it was not the clutch in the TC so I bough a piston and the scotch bright, drooped the pan and took out the piston only to find I already had the updated piston and spring in it.
I had already tried the additive and that it did not seem to help so then I found out I already had the new TC with no drain plug so I flushed it at the radiator and refilled it with Mercon V (5) ATF.
I just drove it for a while and then it went away on its own but I can not say when but it took a little while. So I just deiced that the Mercon V (5) ATF fixed it as others had said it would and left it at that.