I HAVE A 98 F-150 4.6 AUTO O.R.P. AND I AM FELLING A SLIP FEELING ON TAKE OFF FROM STOP FEELS LIKE SOMETHING IS IN THE BED OF THE TRUCK AND IS MOVING ON TAKEOFF..CANNOT PINPOINT BETWEEN TRANS. OR REAREND IT DOES HAVE LIMITED SLIP REAREND ALSO SEEMS WORSE WITH WEIGHT IN TRUCK........ANYBODY HAVE SOMETHING LIKE THIS HAPPEN IT IS DRIVING ME NUTS TRUCK ONLY HAS 14K MILES

 

Hi JCTruck:

I have a similar condition with my '97 4x4.

Recently I had the truck in for service and requested the Ford Service Writer investigate the problem. After the mechanic test-drove the truck, he stated to me that the noise was wind-up in the rear axle (springs?) initiated under braking. The mechanic said the clunking noise on takeoff was typical, and was not a problem.

Personally, I am a bit skeptical about this explanation, but for the time being, I am pacified.

Hope this helps. Perhaps another F-150 Online Member can shed more light on the subject.

Wilk

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'97 F-150 4x4 Super Cab; XLT 139" Wheelbase Flairside; Silver Frost Clearcoat; 4.6L. (Romeo); 4-spd Automatic Transmission; Preferred Equipment Package 507A; 3.55 Limited Slip Axle; Electronic Shift 4x4; California Emissions; Sliding Rear Window; Trailer Towing Package; Off-Road Package; 6-Way Power Driver's Seat; Remote Keyless Entry/Anti Theft; 6-Disc CD Changer; Ford Bedliner; Ford Running Boards; Ford 600 Plus Vehicle Security System; Ford Nose Mask; Roll n Lock Tonneau Cover; Ford PremiumCare Extended Service Plan (5 year/100,000 miles).

2000 SVT F-150 LIGHTNING XLT; 120" Wheelbase; Flareside; 5.4L EFI SOHC V8 SC Engine; 4-SPD Automatic; Silver Clearcoat Metallic; SVT Online Store Lightning Front End Mask; Roll n Lock Tonneau Cover.

[This message has been edited by wilywilky (edited 02-25-2001).]

 

JC, lube or have lubed the slip yoke. THis will cure your problem.

 

The way to tell for sure that it's the drive shaft yoke is to come to a few very gentle stops where the truck remains level at all times, then hit the gas. Then, come to a few hard stops, where the nose of the truck dips down and the rear goes up. Then hit the gas.

If the clunk only happens after you come to the hard stop, then get your slip yoke lubed.

If it happens no matter how you stop, then it's probably something else.

 

not to sound to stupid but where is slip yoke located i thought it was bearing on driveshaft but truck does not have one
thanks

 

I think the slip yoke is up by your transfer case on the rear driveshaft. It's not really a bearing per se . . .more like a splined shaft over a shaft i think; along the lines of a Power Take-Off concept. its purpose is to shorten/lenthen the driveshaft as your axle twists (braking/acceleration) or as your load in the bed changes. that is probably why it is worse with a load. it is also often worse after you take off from a hard stop. When mine would let go, it even made the rear differential gears clunk.

 

If none of those solutions work, drain and fill your rear-end. My buddy had the same probelm on his shovie Z-71, and that did the trick!

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MY TRUCK:

99 F-150 4x4, 5.4 Triton, 3.55 gears, Amazon Green-Harvest Gold two-tone.

MY MODIFICATIONS:

Lund bug shield

Window vent visors

17" Chrome ORP wheels

Clarion Pro-Audio in-dash CD

Connex 3300HP CB radio, K-40 antenna

Husky floor liners

Custom dual exhaust w/Flowmster muffler and dual 3" chrome tips

Hidden hitch

K&N Filter

SUPERCHIP FLIP CHIP....expected delivery 2-27-01

Extang tonneu cover

Rancho RSX Shocks

 

Not a stupid question at all. Just follow your drive shaft towards the front. The yoke is the part that's sticking into the back of the transmission or transfer case.

 

I agree, had the exact same prob with mine, a little lube on the yoke, and no more noises.

been about 10k since that, and all is still well.



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Bambino Online
Owners Gallery Truck #179
1999 reg cab/short box/ORP - 3.55; 4.6l 5sp; factory snapless tonneau; twin 6" kicker sub tubes; Custom Exhaust

 

i believe nomopar4me is correct. you are probably feeling the yoke move. it is probably sticking a little. have it serviced before it needs to be replaced. had the same experience on my '94 F150 4x4.

 

I had that EXACT problem on my 97! They thought I was an idiot!? I was starting to feel like on after the 5th trip in for it! If it's the same thing I had, it sounds like a gallon of washer solvent rolling to the rear of the trunk when you take off, right? They tried the slip yoke lube. No luck. They replaced the whole driveshaft. No beans. Then they tried the u-joint yoke on the pinion... Nope. 4th time was the driveshaft assembly again. Finally, they replaced both of the rear spring packs. Never came back in the next 25,000 miles.

The way I discovered it was I hauled a load of lumber and concrete in the bed for my father. With the weight in the bed, it didn't make the noise. As soon as we unloaded it, I took it for a ride and it did it again.... that's what pointed me towards the suspension. It was exactly what wilk said.... axle windup and a shifting spring. However, it's DEFINATELY not normal.... if it was, it would have done it from the factory.

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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.

 

THANKS FOR THE REPLIES AS FOR THE DIFFERENCE IN THE CLUNK IT IS A LOT WORSE WITH MY PLOW ON WITH NO WEIGHT IN BACK OF TRUCK SO I AM NOT SURE ABOUT THE LEAF SPRINGS CAUSING IT
MADE APPOINTMENT WITH DEALER SINCE ONLY ABOUT A MONTH LEFT ON MY WARRANTY.
IS THE SLIP YOKE A NORMAL ITEM THE DEALER WOULD LUBE ON ANY KIND OF SERVICE?

 

Actually, there's a TSB or something on the "clunk." My '97's clunk was fixed under warranty.

 

The fact that when you lighten the rear end (i.e. put on the plow) it gets worse, leads me to believe it is in the rear suspension.

The TSB on the problem calls for the inspection and lubing of the slip yoke. Most dealers ignore it unless someone complains about it, as it's not a very common problem. Try loading a pile of something into the bed (like a 4 wheeler or a snowmobile, or maybe just a bunch of friends... something REALLY heavy!) and see if that makes it stop. I suspect it's the springs.