2004 F-150 5.4L 4WD

I recently noticed that every once in a while i will feel a quick vibrating/grinding sensation if i accelerate a little too much when going around 40-50 mph. It is very quick (maybe half second). Far from a car expert but it seems like if it were a transmission or rear differential issue it would be more constant or consistent. I do have a rear differential leak that i plan on getting fixed pretty soon, however, the level was just checked and it is fine.

In addition, i have noticed a jolt sensation as i am going up the incline at my gf's apt complex from time to time. It is just a slight jerk as if my truck is going into some type of overdrive mode or something.

I am sure both of these could stem from a variety of issues but has anyone experienced anything similar with a pickup truck? Any idea what could be going on??? tia

When were the last time the transmission fluid changed/?

Also check your u joints.

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slight jerk as if my truck is going into some type of overdrive mode or something.

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No biggie, that's just V-Tec kicking in

I have never changed the trans fluid. I have 94k miles on it. A while back, when I was around 75k miles or so I read an article stating not to change transmission fluid if you haven't done so regularly every 30k miles as it may do more harm than good. I had never heard that argument...sounds crazy but the write up was pretty convincing...I'll try to find it.

V-Tec? Excuse my ignorance.

V-Tec is the secondary cams that engage at high RPMs in some Honda models, don't worry about that.

I would go with 1ags' advice on checking the universal joints, I had one messed up on my 2000 Z71 a few weeks back and no big deal, 15-20 dollar part and you should be able to fix it yourself pretty easily. I had the same kind of rumble but at about 55 mph...

I would change the fluid regardless. Ford has a 100K interval on 'normal' driving conditions.

The main thing is to not flush the system. Drop the pan, change the filter and top off with fresh fluid.

Flushing will shock the system and opens you up to problems.

txag2008 had some vibration issues with his F150 and replaced the coilpack - said it was fine after doing that repair

SL...



OP, listen to 1ags, not us morons - we're just joking with you.

Good advice, I will be sure to change fluid and filter. How would one "check" the u joints? Or do you guys mean just replace them and see if it fixes the problem?

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V-Tec is the secondary cams that engage at high RPMs in some Honda models, don't worry about that.

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Well shat...I could've sworn Vtec kicked in around 3700 RPM with my TBI

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txag2008 had some vibration issues with his F150 and replaced the coilpack - said it was fine after doing that repair

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There are no coil packs on any 04+ V8 Powered F150s. They're all coil on plug.

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Good advice, I will be sure to change fluid and filter. How would one "check" the u joints? Or do you guys mean just replace them and see if it fixes the problem?

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Grab the driveshaft, move it up and down, left and right, if its clunking, then the joints are shot. Also listen for squeaks or whining when going down the road.

Same thing happened in my 2005 5.4L. Between 40-50 mph in 4th gear the tranny would slip. It also slipped at wide open throttle. It's your transmission.

Sh** i hope not. I thought slipping was when it fell back into a different gear or tried to? This is just a quick gringing/vibration as it is still progressing fwd through the gears.

Did you end up having to get a new transmission? What did that run you?

[This message has been edited by Charles Bronson (edited 1/30/2012 1:50p).]

I dumped it. Got a 2012 FX4. I talked to a subcontractor today who had a 2006 that was doing the same thing. He said something about the syncronizers were bad? He dumped his too for the same truck I got lol.

[This message has been edited by ArmedAg94 (edited 1/30/2012 2:51p).]