Has anyone ever experienced this? IT ocurrs when I have been at a complete stop, and begin to accelerate, only after the truck has gone one or two feet. It seems like it is coming from the rear end, and it jolts the truck a bit like the wheels hit a patch of ice, and then regained traction, though the road is dry. Thanks for any info...
scott

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2001 F-140 SuperCrew 4X4 Lariot
5.4, 3.55 LS, Wimpy stock 17" tires
-MB Quart Reference, 2 JL-8W0

 

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I get the same thing from the rear end of my new 2001 F-150 extended cab. When you start to drive it makes a thud noise. I just got this truck 2 weeks ago. I traded my 2000 F-150 regular cab because service engine soon light kept coming on, also the engine idle was rough since it came off the lot. This truck is much better.


2001 F-150 Extended cab
4x4
3.55
5.4L
XLT

 

I had a similar noise on my 97... does the engine rev, or does it feel real sluggish initially? Could be a trans problem, or could be suspension...

On my 97, it was one of the rear spring leafs shifting.... it actually felt like a bottle of washer solvent rolling around the trunk of a car, and happened every time on throttle tip-in (felt like a bottle of washer solvent rolling to the back of a trunk). How I discovered it was something in the suspension is when I loaded up some lumber and cement in the bed, the sound disappeared. They replaced both rear spring packs and it fixed it.

-Joe-


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98 Explorer (Lemon Law Case in Progress)

'00 F-150, X-cab, 4x4, Lariat, Off-road, Trailer Tow, Holandia Sunroof, built 11/99 picked up 10/00!Clear Corners, Manik Stainless Steel 1-piece brush guard, Custom CB wiring, Uniden PC76-XLW CB radio with K-40 Magna-Mount antenna (for now), 1 set of 165 watt KC Daylighters (for now... more on the way) Custom switch mounting plate and overhead console, Bully Stainless Steel Trailer hitch drawbarw/ 2" stainless steel ball.
List of planned mods: Clear tails, torsion bar tweak, bug deflector, spray in liner, and a tonneau of some sort...

93 Probe GT teal, OE rims painted to match, bone stock drivetrain.

 

Joe, Thanks alot, now that I think of it, that is exactly what it sounds like. I'm assuming that a visual inspection would not reveal anything...Thanks again,
Scott

 

Visually, I couldn't see anything wrong at all. In fact, I'm not even 100% sure they verified the problem before ordering it... it had been in for it three times prior to that time, so I think they might've just been sick of seeing my face!

 

the symptoms you describe are often explained by a sticking "yoke". it is located at the front of the rear drive shaft. it's purpose is to allow the driveshafte to "change length" as the load in the truck varies. it will often "let go" as you accelerate from a stop . .it can even make you rear differential clunk . . .

 

It could be the yoke too... forgot about that... that was one of the first things they tried for mine... didn't fix it. Then, they tried replacing the driveshaft, then the rear pinion, then the pinion bearings (because they messed up the backlash/pre-load on the pinion the first time and torched the bearings, diff, etc, etc...) then they tried the tail-shaft of the trans, all before they discovered the springs.

-Joe-

 

I have the same problem in my 99 extended cab 4x4. The dealer tightened the u bolts first. Didn't fix the problem. Then dealer "drive train" expert said it was the yolk. Greased it up and it quit for a while and now it is back. Had it in again and to replace the yolk but the tech said nothing was wrong with the one in it. Still hear the clunk and am not sure if I will get the yolk replaced or not.
Any suggestions about the springs?
Will this clunk cause other problems in the rear diff or transfer case?

 

Load it with about 800+ lbs of anything you can find... lumber, snow, logs, drunken friends, etc... if it goes away, it's in the suspension. If not, it's in the driveline.

-Joe-

 

I also have this slight "klunk" on my '01 SCrew, just as 5.4x4 describes. Service Manager said it was "normal" because of the length of the drive shaft. Is this true? Is there a fix for this, or just a quirk of our drive systems that we gotta live with?

[This message has been edited by sundog7 (edited 03-19-2001).]

 

Thanks Joe,
I'll try that. I have this really bad feeling it is the slip yolk though. What about it recking the drivetrain?

 

Thanks againg Joe,
I think I will call my Ford dealer and see if there is a tsb on this or something. I will let you know, and if possible will have them order me the springs to fix this problem. Definately making use of the extended warranty here to my dismay.

 

It's possible, but they tried that for me too... it had the same effect... seemed to mysteriously disappear for about the duration of the trip home from the dealer (about 50 miles). Came right back. I suspect it goes away not because they lube the slip yoke, but because the suspension goes to full droop and something in the springs re-aligns itself for a short time. I finally had to take the service manager for a ride and show him exactly what it was doing... I showed him, then let him drive it to feel it. It had definately disappeared after they lubed the yoke, but it did come back (verified by him as well) every time until they replaced the springs. I'm not saying for sure that's your problem, but that was mine... drove me CRAZY!

-Joe-