How low does the fuel in the tank need to be before changing sending unit. I just filled up before I got my sending unit and have only used about 10-12 gallons.

Hello & Welcome Jiru:

I would suggest that the tank be below ½ before you replace the fuel sending unit.

Thanks Dave-that was my guess but just thought I might be able to put it in sooner. Skip

Hey Skip,
Can you tell me where you got the sender from and maybee a part number,I have 99fds that the gauge wont read properly. thanks Ray Fordyce

Skip,
I would be interested in that information also. My gauge is hard over for the first 500 miles so I guess I need to change the sender.

Skip, I am assuming you have the 100 gallon tank, if so you will be fine at the 3/4 mark. I have the 100 Gallon on my '05 an have swapped it 3 time, the last time I did it myself, just crank the wheels all the way to the stop and you can reach in from the street side.

Skip. I would be interested in your source and part number for the fuel sending unit. I have a 99 40FDS and I need to replace the unit but my mechanic is having difficulty finding replacement sending unit. Thank You.

found out wrv used fuel tanks made by Transfer Flow INC 1 800 442 0056 or 530 893 5209
I called them but they dont offer a sending unit.
they refered me to Macs Radiator service
562 920 1871 they are supposed to be able to rebuild our sending units.will try to get hold of them to see if that is possible.