2005 Libby with CRD and the fuel guage just quit working. It has about 120k on it. Anyone ever had this problem is there a float in the tank? Could of sworn when I stop quickly I could hear something sloshing around in the tank. Any ideas?

First thing you need to do is determine if the gauge itself works. I know that may sound odd but the gauge could be dead or the signal to the gauge could be dead or both. You need to run an instrument cluster test by holding down the trip odometer button as you switch on the ignition. Get a copy of the 06 FSM from Sam's NOOB site (even if you have an 05 - 05 FSM lacks diesel cooling system info and general diagnostics but has illustration keys while 06 is the reverse) and look at the Instrument Cluster Self Test, (beginning on page 8J-65 and scattered thru various pages to 8J-87) which discusses what the test is supposed to do with respect to various lights and gauges on the dash. If the fuel gauge passes that test then it's ok.

If the gauge is ok then you need to determine if a signal is getting to it. I'm virtually clueless on modern (e.g. post 1970) vehicle electric systems but I'm sure there are tests, see FSM, to the circuits that will tell you if it's getting a signal from the tank. Even something as simple as a continuity test would tell you if the circuit was not broken hence should get a signal. If the curcuit is ok than it's likely the intank system. IIRC there has been at least one forum member who had a tank float go bad. If you are going into the tank anyway while I'm not a big fan of the intank lift pump install (don't dislike the idea just think there are good options that don't require dropping the tank) I'd think about replacing what you have (pretty much just a float assembly minus fuel pump) with the combo (float/pump) assembly. Check with Sir Sam on what to get.

NOTE - do you have an old battery? I ask because a weak battery can do weird things to computerized electrical systems. stoutdog had fuel gauge problems as did I (wildly erratic readings - full to way less than full even zero in like 60 miles) that ultimately went away a few weeks after installing a new battery. Might want to get the battery and alternator output checked.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

Thanks for the help... I havent had time to fart with it yet Ive just been tracking mileage closely, but I did notice the other day that it was reading 3/4 tank which is wher it should have been, but went to a little past full after shutting down and starting back up where it has stayed since the problem first started. I am going to try to tackle it this weekend.

I had the same thing happen in my '05. Ended up being the sending unit in the tank, I was still under warranty and had it fixed by the dealer.

A piece of the unit broke off and was sloshing around in the tank. You could clearly hear it when driving. Mine did the same thing you described, full one day, down to a quarter, down to empty, back to full. It was totally unreliable. I suggest checking on parts to see if they are in stock before dropping the tank. It took the dealer about a week to find and get the parts in hand.