Attention to those replacing the cheap, plastic fuel cover

[CdnHO]

A bit off topic, but what is the purpose of the three splines in the fuel filler neck on the newer diesel trucks?

 

[H3LZSN1P3R]

A bit off topic, but what is the purpose of the three splines in the fuel filler neck on the newer diesel trucks?

My understanding was it helps keep the nozzle centered for using large truck nozzles as with no splines it can get caught on the spring on the nozzle where it goes through the flap

 

[sstoner911]

Even with a fuel cap, you will probably find the AUX tank will leak out the vent....

 

[NewRamGuy]

Even with a fuel cap, you will probably find the AUX tank will leak out the vent....

In my case, only with the fuel cap on does fuel leak out.

 

[NewRamGuy]

My understanding was it helps keep the nozzle centered for using large truck nozzles as with no splines it can get caught on the spring on the nozzle where it goes through the flap

That makes sense.

 

[sstoner911]

In my case, only with the fuel cap on does fuel leak out.

When I was looking for tanks the biggest reason I went with a pump fed Tank,
( Titan Trekker 50 gal) was I paranoid about waking up to Diesel all over the ground.

 

[NewRamGuy]

When I was looking for tanks the biggest reason I went with a pump fed Tank,
( Titan Trekker 50 gal) was I paranoid about waking up to Diesel all over the ground.

I get that. Honestly, never knew I had an issue (and at the risk of beating a very dead horse, I didn’t have an issue) until I used the aftermarket fuel cap which started this discussion in the first place.

 

[H3LZSN1P3R]

I get that. Honestly, never knew I had an issue (and at the risk of beating a very dead horse, I didn’t have an issue) until I used the aftermarket fuel cap which started this discussion in the first place.

Im actually rather impressed and confused on how it worked for you without the float valve as i figured fuel would come out of the tank vent

 

[NewRamGuy]

Im actually rather impressed and confused on how it worked for you without the float valve as i figured fuel would come out of the tank vent

I genuinely have no answer other than to point out with my setup the fuel hose going from the auxiliary tank to the truck fuel tank connects to the fill spout approximately 6” below the (now infamous) convex metal cap.
This may not necessarily pertain to the discussion but I never fill the auxiliary tank more than 80-85 gallons total (it’s a 91 gallon tank) so that no fuel leaks out of the auxiliary tank vent hose. I learned that lesson the hard way when I first ran the same tank in my ‘18 F-250.
This is not a commercial but my tank is an RDS model with a shallow (6-8 inch) ‘tool box’ on the top. The entire top is covered so that it appears to be a tool box rather than a combination setup. Both the fill inlet and the storage are accessible when the lid is raised.