I just picked up my '05 XLT Supercab last week and have noticed a clunk from time to time - sounds like it's coming from the rear.

The truck does have the 3.73 limited slip rear.

It only happens whe I step on the gas a little harder than usual. I'm not talking about mashing the pedal - just a little more throttle than usual acceleration. I think it's probably the clutches in the diff. So - for those with limited slip rears - is this normal, or should I have it looked at?

Thanks,

Rick

 

You might want to check the yoke on your drive shaft.

 

I have an 04 Lariat 4x4 SCab w/3:73 LS and no clunks yet.(cossing my fingers) Anyway, I would take it in and start a file just in case you need it later.Good Luck and keep us posted!

 

Welcome to the drive train thump club. I have the same issue and Ford is attempting the fix. For what ever reason there is not a smooth transition of the power from the drive shaft to the rear axle, apparently it is a problem with the meshing of the splines from the shaft to the rear axle. The initial fix is a teflon grease that is supposed to smooth it out. That did not work so I'm waiting for fix #2. I'm waiting for a new drive shaft. I was told last week that there are none to be found and that it could be as long as a 2 week wait. I was curious and asked the service writer how they knew it was the splines on the shaft and not the splines in the rear. They responded with, this is the sequence of the procedures that is to be followed as per Ford. I would bet that fix #3 will be a new rear and drive shaft. In any event I'll have to wait for the drive shaft. I found it odd that there was not one available unless the problem is more widespread. Like you mention it depends on the amount of acceleration. If I start at a snails pace its not as noticeable. If its a medium takeoff its most noticable for a few seconds. If its a speedy takeoff its barely noticeable. The problem started when it hit 3,000 miles. So there you have it. If this sounds like the problem you are experiencing tell them you have a drive train thump and get the ball rolling on the fix. Uncrichie...

 

Im part of the clung gang too. Its like it doesnt put the power to the rear end for 1/2 a second. I havent went to the dealer yet but I think I will. I have the limited slip 3:73 rear end on the FX4 2004 Crew.

 

ford knows about the problem and has a new kit to solve he problem. i have a 04 xlt 355s . the kit was on a national back order till april 19 still did not get my parts , dealer told me new date may 23 they said ford cant keep up the demand for these parts! i think the parts are a new ring and pinion and some other fun stuff . hope this is the fix cause i had this trouble since nov. among other trouble with the motor

 

I just had the work done on mine this past Friday. Along with the other mentioned parts was a new drive shaft. It is smooth as silk however I'll hold out my final answer for at least another 1k miles. Uncrichie...

 

I've had my '05 5.4L Lariat SuperCrew with a 3.55 limited slip rear end for a little more than two months now. Bad news is she's been in the shop 8 times for a "read-end clunk." I take her to the best Ford service dealership in Austin where they've replaced everything from driveshafts to valve bodies to ring and pinion gears to gaskets. No luck. She still clunks when shifting and it's getting worse. I've been on test drives with a Ford engineers, service managers and consultants. They simply scratch their heads and say, "I don't think that's supposed to do that." So good luck to ya'll who are having the same problem I am. PLEASE let me know if any of your "mechanics" (HA!) figure anything out.

I will have to say that I can't knock the dealership as they've bent over backwards to accommodate me in every way - a free ESP plan, unlimited REALLY NICE car rentals, free fill-ups - you name it. These guys rock as far as customer service.

 

mranderson, If failure at your dealership service dept. continues I would ask for another truck or try a different service dept.Good Luck!

 

I've already done both. Tried two other service depts, both sucked! If the truck doesn't "pop a code" they're unwilling to even look at it. Argh! My current dealership is backing me up and pushing for the the lemon law on my truck which should finalize in a few more months. I have utmost faith that the problem isn't going to fix itself or be fixed by Ford so I believe a new truck is a more-than-likely possibility.