I noticed this weekend that when i'm cruising between 39-43mph i get a really weird shake. The entire truck sorta jolts back and forth. I'm not sure if it's an engine problem or a tranny problem. It doesn't happen if i'm still accelerating hard (like when i'm merging onto the highway), and i notice it the most when going uphill. But i also notice it a little on a level surface and when going downhill, but its very subtle. I have a '98 F150 w/the 5.4L. There aren't any weird noises coming out of the engine or tranny, or any other part of the drivetrain. It's a weird kinda feeling. When the shaking occurs, it feels like you're going over some bumps on the road. So i'm wondering if maybe a piston is misfiring? Or maybe i'ts a transmission problem?

-beats me, i don't have a clue as to what it could be. Any help is greatly appreciated. I'll probably be taking the truck in for service in about 3 weeks. Luckily the dealer gave me a 90 day warranty when i bought it (3 weeks ago) so it shouldn't cost me anything.

 

Hmmm, maybe tranny tail shaft (but you'd probably see leaking AFT) or a driveshaft? Just taking a guess.

 

whats that?

-actually i was at my cousins house this weekend and when i backed out of his driveway there was a puddle there. I didnt notice it until i was too far away to determine what it was. I figured (or actually hoping) it was just some water. It could have been a leak from somewhere else though......i sure hope not though

 

Ok, now I have to go back and edit this. First Familyride meant ATF or Automatic Transmission Fluid. Second check your tranny fluid and if more spots appear under your truck get out and check.

Now here was the first part of my story before I had to edit.
Do you have the 4R70W behind that 5.4? If so that really makes me think it might be TC shudder.
I am expereincing the same thing yet I haven't had the money to let a dealer start makin repairs. I have read through the tranny section here and have learned a lot about TC shudder and the tailshaft problem. It seems to me the tailshaft problem is more related to the 4x2's as in our 4x4's your driveshaft comes out of the t-case. I also learned a lot about Ford AOD's, AODE's, and the 4R70W's from www.tccoa.com/articles/misc/index.html#. It's mostly for the t-birds and older Ford cars but alot of the knowledge applies here too.

Take for example this clip from that site:
"External cooler have always been recommended for better cooling of the transmission. Vehicles equipped with an AODE or 4R70W transmission may experience a torque converter clutch shudder or vibration. This occurs under light to moderate acceleration above 56 km/h (35 mph) while in 3rd or 4th gear. This may be due to either transmission fluid breakdown and/or the Powertrain Control Module (PCM) calibration.Ford TSB 98-3-6 recommends Mercon V for AODE-4R70W trannys to cure Torque Converter shudder. I know that Crown Vics, & Town Cars use this tranny. Isn't This the same tranny in '94 & up Tbirds? If so, I recommand it, as I have seen it work in the local Crown Vics."

Good luck and let me know what happens

 

yeah, after reading up, it sounda like it could be TC shudder.

to be honest with you, i don't know what tranny i have. I haven't looked yet. But, that link above, described exactly what it feels like.

 

Dan
What kind of miles do you have on that truck and when was the last time you had the tranny fluid changed?

 

the engine has 46,076 miles on it. I bought it 3 weeks ago. The dealer told me that they serviced it before they put it out on the lot for sale, so i can't really say when the last time the fluid was changed. My spring break is coming up here in 2 weeks, so i'm gonna take it in and have them look at it. The dealer gave me a 90 day 4,000 mile warranty, so hopefully they won't try to charge me anything. At least they shouldn't.

 

DanB, when my spark plugs went bad, this was the first thing that happened to me, then it started getting worse until it shuddered all of the time. Do you have any flashing Check Engine light or anything like that while the shuddering happens?

 

those are the exact same things my truck did when the tires were out of balance. maybe thats all it is...

 

no, i don't have any lights coming on.

 

I had this problem twice already with my '99 5.4L 4 X 4. Both times the dealer told me they replaced the ignition coil. First was a loose clamp alowing coolant to drip on the wiring. Second time was a connector that loosened; both times they replaced the ignition coil. Only shook when slightly giving it gas. But the second time the engine light came on, and shook every time I accelerated all the way to the dealer(They wouldn't pay for the towing). The truck's been fine now for about 12K since the last time. (Now have 31K)Good luck!

 

I had a simular problem with my truck starting around 15 K miles , a slight vibration or puling feeling from the powertrain . Take your truck into a tire dealer not the ford dealer . Although I had the necessary service work done , they( ford )never noticed tire cuping. That was my answer , a new set of tires and not G/y's

If you have uneven ware on the outside of your tires , that's what it will be .

98 4x4 auto 4.6 sc, 26000 miles

 

I had (have) a vibration btween 40 and 45 MPH. Turns out its 2 of the 4 four factory Goodyear AT/S tries have excessive runout.
Ford put a reed tachometer in it and took it for a drive, and it indicated a secondary tire problem.

The Goodyear dealer I took it to, said their was no problem, then after I went to Fod again, they put the tires on a balancer and watched it 'hop'. I just came from another tire dealer, who jacked up the truck, put it in gear watched the tires spin, and said, "Yeah, it's got excessive runout, didn't Ford do this?."

He then told me Goodyear has had a lot of problems with their tires recently. The 2 tires are being prorated and they're being mounted next Friday, then on Sat all 4 GY are coming off and 4 new tires are going on Sat.

 

Excessive runout - Sounds like the exact problem that I am having! My vibration is in the rear end, between 62 and 66 mph. I also have wear on the outside front tire, drivers side. I first noticed this at 3,000 miles..and the truck now has a little over 12,000 miles now. I've had the alignment checked and rotated the tires. I was beginning to think I had a warped rotor or bigger problem.

Thank you for the information. I might just trade in my tires and get rid of this vibration once and for all!!

 

Do you feel the vibration through the floor and gas pedal as opposed to the steering wheel? If so, it is most likely TC (torque converter) shudder. Contrary to popular belief, this is not isolated to the 4r70 transmission. I have the 4r100 and mine started doing this at ~20k miles. Mine was fixed under warranty. The dealer did both a software update and changed the fluid, so I can't say for certain which of these actually fixed the problem...possibly both are required.

If your shake or vibration is from the steering wheel, I'd consider checking out the tire issue. THough I still don't understand entirely, I had a pickup that had to have the tires balanced on a lug adapter to stop the shimmy. For some reason, every time the tires were balanced on the hub (typical technique), they would balance fine on the machine, however, once they were mounted on the truck they had a noticeable bounce.