Anyone have a problem with thier rear end and tranny? (truck spec in the sig) Once in awhile when I'm sitting and get on the gas, the there is a big shudder or thud in the rear of the truck. Kind of like something hitting the tailgate after sliding the length of the truck. (this is not the case) Sometimes it's a hard hit and sometimes it's just barely noticible. And it doesn't happen all the time. Just once in awhile.

It's really nerve racking. I half expect the rear to fall out of the truck. I know there are people who are gonna say, "It's a truck, you shoulnd't be pounding on the gas." But, hell it's fun.

Has anyone seen or heard about this before?

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bIGGINS
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My New Ride->>
2001 F-150XLT 4X4 Sport SuperCab
Styleside, Short Bed, Black on Black, 4R70W, 5.4L, 3.55reg, 17in Rubber, OEM Snapless Tonneau Cover, Harley Bedliner
Add On's
Sony CDX-M770 Head Unit, (2) JLAudio 8W6's, RF Punch 150 amp, HL Blackouts, DashMiser Plus II Strobe Light (fireman)
My Last Ride->>
1999 F-150XLT 4X4 Reg Cab
Styleside, Long Bed, Amazon Green, 4R70W, 4.2L V6, 3.55reg, 16in Bridgestone Duelers, OEM Snapless Tonneau Cover

 

My truck does this, too. I think it's a bad motor mount, though.

-Jay
98 F150 SC 4x4 ORP
33x12.5 Pro COmp At's
Transgo shift kit
K&N filter
VGX pads
JL sub and Kenwood amp
custom 4 wheeling modified bumpers by tree and stump

 

I started noticing it just after I bought it. It happens after I take a turn and apply the gas.

Don

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2001 F150 SC 2X4
Arizona Beige
Short Box
5.4L
3.55 LS
Captain's Chairs
Power Seats
Sliding Rear Window
Tow Package
Herculiner Bed-liner
Bug Shield
Hard ARE Tonnaeu Cover
1.01 soon to be 1.42 Radiator

 

this seems to happen in my truck to, though its not really audible, i feel it through my shifter... only happens about once every 25 launches and only when starting in 1st from a standstill. my truck's new so i'm just going to keep an eye on it and see if it increases in frequecy.

my roomates truck ('91 chevy 4x4, 350, 5-spd) did the same thing and we almost eliminated the thud by tightening down the u-bolts that hold the rear axle to the leaf springs... in his the pinion angle was positive (you want it to be a bit negative because when you accelerate the rearend rotates up and it then be level with the driveshaft) and that is what was causing the thud. his still thuds a little, but not nearly as bad as before, and considering he has 191,000 miles, its not too bad.

It could also possibly be that the pinion isnt tightend down enough... this happened in another of my friend's trucks. unless you have a monster impact wrench or like destroying craftsman breaker bars you'll have to get a shop to get down on that nut.

these are just a few ideas... i hope mine doesnt get any worse and i hope you can fix yours... good luck!

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2001 F-150 XL SWB
4.2L 5-spd, 3.55
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Other Cars:
2001 F-150 SuperCrew (Dad's) XLT, 5.4L, Towing Package w/wrong radiator.
1994 Honda Civic DX Hatchback, 1.5L, 5-spd. Shared it with my sister in high school... recently totaled when she was driving with only 1 contact lens in.
1983 Chevy Camaro (Roomate's) 383 Stroker, Tremec T-5, 4.10, AFR Heads, Edelbrock Intake, custom cam, etc... ~500 hp (not quite built yet)
1997 Saturn SL(ow) (Girlfriend's) Breaks down alot... also equipped with firestone death-tires as we found out a couple of weeks ago while going 75 mph... luckily she managed to pull it off the highway safely.

University of Texas at Austin, Class of 2001

 

i think the only thing in common on our trucks are the 3.55 gears... i've heard there are some problems with these gears so maybe thats it... do yall have an 8.8 or 9.25? (mine's an 8.8 obviously)

 

I was checking out some other posts and there were a few on this. Looks like it's either the leaf springs or the yoke on the drive shaft. I'm taking it in and we'll see what the dealer says.

 

I had a 97 F150 that did the same thing. After several trips to the dealer they put a new drive shaft in it. The problem was solved.
Later on after talking to some other people I was told that if we had just put grease on the splines where the shaft slid into the transmission that would have probably solved it.

Marvin

 

Maybe Ford and GM have a similar problem.

From a GM board:
http://209.35.112.209/performance-discussion.html

 

In case you couldn't see the correct link, here is one of the posts on that message board. This is the sentence I noticed regarding a noise problem. "The spline simply sticks until enough force is exerted and then you feel it give".


re: fixed the clunk in the tahoe tonite

I had the same deal, I freaked out and thought my rear end was going or something was rolling around in the back. Brought it into the dealer. They called me back in an hour and said "Ready for pick-up!"

I talked to the mech and he said he took the shaft out cleaned it, greased it and put it back in (Ha, Ha, aaaaaaaaaa, he said shaft, ah, [sk0.JurRh..2 beavis). He said if it ever happens again bring it on down. Guess it all depends on your dealer- I've got a great one- Carlsbad, CA. The spline simply sticks until enough force is exerted and then you feel it give. Too bad you had to do all that work, I'd at least ask for a free oil change....Tim