Just bought a 1998 Lariat flareside, 5.4L Triton, all stock.

When accelarating from a dead stop, I get a rear-end rumble.

The best way I can explain a rumble is to go to the highway and drive slowly down the rumble strip on the shoulder of the highway.

No excessive wear on any tires, grabbed ahold of the tires to check wheel bearings (they are tight), I checked the U-joints (all good there), No diff leaks which would imply an shaft bearing. I just pulled some tough tree stumps with it, so transmission is golden. I am stumped.

Cheers for any help you can provide.

 

what kind of tires are on there? i know mine rumble at 3 mph. the truck noticeably shakes at 3 mph going to a stop and starting from a stop all due to the tires.

 

I had this problem on my '04. Ended up being the torque converter.

 

Well, these are standard Steel belted radials. Nothing special. The rumble does feel like I have a mud traction tire on the back end and trying to drive on it.

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Torque converter?? I didn't think of that. It does have plenty of torque. With your torque converter a problem, did you still have some pulling power??

 

yea, your still going to have pulling power. But, the longer you let it go, the worse it gets. I pull a bass boat alot and when I was having problems with the TQ it was alot worse when I pulled the boat. Mainly when the tranny was at its shifting points. Can't really explain it like my mechanic can. At first he poured a bottle of shutter stop in my tranny. He said sometimes that can cure the problem if it aint too far gone. I tried that and it helped for a couple hundred miles, but eventually came back. I would atleast get it checked out. Probably wouldn't hurt to get your tranny flushed and filled that may help.....sometimes simple things like that can cure a problem. Good luck.

 

Well, the previous owner did sell this truck to get something more Beafy. What that implies is he had something heavy to tow, and needed something with more juice. If this isn't designed to tow heavy things, I could see this as being the potential problems.

"Shutter" is a good word for this.

What do you think of going to a high performance shop and getting a high proformance parts, like a torque converter?

 

Don't know what are all the options for a new TQ, but the stock TQ really should provide all you need. I would check around for the best price. Maybe, someone makes a high performance TQ....never know.

 

It's possible that it's limited slip clutch chatter.

Exactly how did you check the u-joints? They can look and feel fine with the driveshaft in place, but they can still be dry and sticky.

 

I just took my 04 into Ford today because it was shuttering or rumbling on acceleration. Turned out that the clutch packs in the rear were going to hel. The bill was just over $800.00. Fixed the problem though.

 

Well,

I just purchased this vehicle. So, I am working on the bugs, right now. Wish I could afford a brand spanking new baby.

I rolled down the windows, to see if I could hear a bit more when it "shutters". I find that either the left or right tire will skip on bare pavement, causing the shutter feel. So, I am thinking a rear end diff lock. Remember, I was trying to say that this only happnes turning right or left and accelerating from a dead stop. A rear end diff lock would do this.

But, I think a limited clutch slip would also do this going straight forward.

Please, tell me of your opinion on this logic. With this added info: Would, the clutch packs in the rear cause the skipping tire upon turning right/left from a dead stop? Or, do you think it's a diff lock?

I did have this same symptoms on my 94 Bronco and All I know is this drive train shop charged me $1200 dollars to fix. The dealer mechanic was scratching his head, somewhat like I am, now.

Besides this ONE issue, I have NEVER had a problem with any FORD I have ever been in. Par for the course is, Oil every 3,000 gas, lube, and all systems go. This includes two Broncos I took over 250k a piece on.

 

Oh, ok, its doing it from dead stop either turning left or right. Sounds like rear end to me. I had that same problem last summer. Before I took it to the dealership, I read where some people were changing their diff. fluid. I done that, and added friction modifier and now there's no more chatter in the rearend.

It may come back, but its been chatter free for almost 6 months now. I would atleast try that first before sending it to the dealer. JMO

 

Change the diff fluid. 75W140 full synthetic and friction modifier.