I have a 2001 supercrew with 800 miles on it. It has a 5.4, 4x4, 3.55 limited slip. Whenever I accelaerate from a full stop, I hear and feel a clunk from the differntial. The dealer tells me that is normal for all F-150's. He added that expeditions don't have this sound becuase they are automatic 4x4's.

Is this true, or am I being feed a whole lot of B.S. I cant beleive that a $33,000 truck makes sounds that you dont get from a $600 lawn tractor. Please Help.

 

You need to be more specific and tell us exactly when(speed, how much throttle, 4x4 off or on, etc. ) it happens and how you know it is the diff that it is coming from. The last line from the dealer is bull of course, but you knew it was.

 

I believe this is a different symptom than the famed "tranny thunk" I also have experienced what I would call a sudden grabbing or slipping when taking off from zero. I beleive it ha gotten less noticeable, but maybe I'm just getting used to it. I have 1800 miles on my SCrew. I have not experienced the same symptoms know and the tranny thunk. I also have not asked the dealer about it. Just haven't had time. It is the only complaint I have about my truck and therefore has not bothered me much.

------------------
Gen III
4x4 Lariat
5.4
Lmtd Slip, 3.55
ORP
Tow Package
Oxford White/Az Beige
Med Parchment leather
Heated captains chairs
Moonroof
Slider
Bed extender
CD Changer

Ordered 1/11/01
Arrived at Dealer 2/28/01

 

If its coming from the back its probably the ls. People will say it shouldnt do that, but if you talk to an engineer that helps make them or a differintial expert they'll say its normal. If you hear it when you take your foot off of the gas and coast alittle its the same thing.

 

If its really bad its not normal and there could be alot of things wrong that cause the sound

 

Thanks for the response. I hear the clunk while I am in 2wd drive mode, under light and medium acceleration. I normally hear and feel the clunk at about 2 or 3 mph as I am accelerating from a full stop at light or stop sign. I think its the differintial because the sound seems to be coming from back there. I can actually feel the back of the truck (differntial) slightly torque/twist when I hear the clunk.

When I called the dealer, the service technician told me that Ford's engineers had actually flewn out to their dealership on a similiar complaint last year; and that they told them that the differential locks up as the truck starts to accelerate and that its perfectly normal and that it can not be corrected. The ford engineers reportedly informed the dealership employees that the expedition's differntial is differnt because that truck has an automatic 4x4 system.

 

Isn't this the same problem reported (again) in the thread down a page a little in this forum? Look for the topic "Supercrew Tranny Thump". It also references a link to a still-earlier thread about the same thing.