BearKiller

I have had a 52-gallon auxilliary tank, plumbed into the draw-lines, via a three-tank manual selector-valve (I have THREE tanks, two-20s and the 52), ever since 1985, many hundreds of thousands of miles.

I never ever replaced the mechanical lift-pump on the original International 6.9 engine, nor have I ever had any issues with either the diaphragm-pump, or the piston-lift-pump on the Cummins.

I have an in-dash mechanical fuel-pressure gauge.

When I switch from either frame-level factory tank, to the up HIGH on top of the flat auxilliary tank, I always gain from two to three PSI on the fuel-pressure gauge.


I would never consider letting a tank "gravity-flow" into the filler-neck, or however, like many are doing, as the potential for a drastic failure is way too high.


I know of several that have systems such that, should someone remove the factory fuel-cap, all the fuel from the auxilliary would come gushing out.


It is far safer, and way more dependable, to run a dedicated draw-line to the auxilliary, controlled be a manual selector-valve.



Many of the big trucks that I drive have tank outlets at the bottom of the tank, with a cross-over/equalizing line from one tank to the other, that has the draw-line to the lift-pump TEEed into this cross-over.

There are cut-off valves located at each tank, such that either tank can be cut out of the system.

On trucks that are likely to be on un-even ground, one, or the other, valve must be closed, when the tanks are more than half full; reason being that, should one tank be higher than the other, the fuel will flow to the lower tank, over-filling it and pushing the excess out the vent.

To prevent this, both tanks are filled to FULL, one tank's valve is CLOSED, the truck is ran until one tank is down to 1/4, the closed valve is opened, and the FULL tank will level itself with the other tank.




I really enjoy my vast amount of fuel capacity; I can fill up in Kansas City and come to the house, without having to set my feet on the ground.

shortbed rv

My RDS gravity feeds and I leave it on all the time. no problems for 1 1/2 years.

Now the Duramax has a problem. Since the fuel guage does not go down the chevy computer thanks it is not using fuel and shuts down. Those guys leave the valve closed and just open the valve when stopped to refill.

BearKiller

Concrete evidence that they are in cahoots with the big oil companies.

OutlawStorm

Shortbed the reason I have a valve installed is safety reason, and being I am commercial plated in Canada, it has to have either a manual shut off or a electric switch like I have on mine. Personally I would never leave mine on,,as all it takes is a person to walk by and take cap off and then all fuel in aux tank can leak on the ground and for me, Diesel is way to expensive to waste.

GMScott

Maybe a little pricey, but I've had my 98 gal. across the bed TransferFlow setup in 2 different trucks, logging over 400k miles on the unit. Only had one problem and that required a new pump. Unit is DOT approved in all 50 states. Wouldn't be without one ever again!!

haulin-rv

Not correct. Yes the guage goes to empty after it stays on full for about 45 minutes, but it DOES NOT shut anything down. Actually it works rather well when gravity fed, when the aux tank becomes empty and the main tank uses a bit of fuel the guage returns to full. I always looked at it as a way to see when my aux tank was empty. I ran mine for about 300k that way with no issues.

If they made a 75 or 80 that would fit a Dodge shortbed I would have gone that route, the transfer flow systems are nice. But only being able to get 50 or 60 is just not enough for me.

HiJenks

I think GMScott had the secret words....DOT approved...Transfer tanks might not be DOT and therefore not acceptable for use as an auxillary fuel tank.

haulin-rv

The tanks made by RDS and sold by Northern Tool that are aux tanks (not transfer) are all DOT approved. As long as installed and plumbed correctly.

BearKiller

I am always seeing these debates about what is and isn't DOT approved.


Most any fuel-tank I have ever seen, be it home-made or storebought, is much heavier, better built, and safer looking, than any of the flimsy original equipment tanks that I see hanging under trucks.

Factory tanks are paper-thin and slung from flimsy failure-prone little steel bands, ready to rust through and fall on the road.

If they can pass the test, anything should be able to achieve DOT approval.

dadwolf2

This is Northern Tool/RDS legal disclaimer: "It is the users responsibility to comply with local, state and federal requirements pertaining to safe transportation, loading and discharging of tank contents." This way they get to say, I sold them an aluminum tank, it's their problem after it leaves my store

Nascarcamper

I bought (eBay) and installed a used TransferFlow 65 gal tank and box combo designed for a late 90's Ford. Fits perfectly with just enough clearance on all sides without sticking up over the bed rails. I then removed and modified the tank sending/pickup unit with a in tank pump with a in-cab switch for control, from there the fuel goes through a 10 micron in-line filter/water separator, from there to a marine manual three way valve mounted in the tool box with one port connected to the old, un-used, in truck tank vent port since I did the vent mod on my truck long ago, the second port has a marine quick disconnect, this allows me to pump fuel in to my 5th wheel's fuel tank (diesel generator equipped). I have no fuel level gauge installed yet for the aux tank, the gauge for truck does not react very fast while moving down the road and refueling, it takes 20-30 minutes and will never show it as FULL, 7/8 is about as high as it will show until you reset the ECM or BCM with a key off. I guess the computer has a problem with this, but it does not have any ill side effects. The whole system cost me about $300, tank and all. Last trip south ran me through Alabama, fuel was $3.03 at that time, this saved me a bunch compared with Florida at $3.59 a gallon.

haulin-rv

Yes that may be what it says, but my point is the ones that are sold as aux tanks come with the tag that says DOT Approved. The ones that are sold as transfer tanks do not, and also do not have the 3 ports for hose hook up (out, return, and vent).

BearKiller

Where can I get this stuff ??

I have a three-tank four-port manual-valve that is getting a lot of use on it.

I would like to have a new one laying around, but they are not as common as they once were.

Thanks.

Nascarcamper

Found all my fittings and the valve on eBay, the guys name is "contactbpd1" he sells all kinds of marine hardware and supplies, From the add:
Discount-Marine-Supply
4882 Slans Island Rd.
Hollywood, SC 29449
E-mail: contactbpd1@aol.com
Phone:
Bill @ (813) 784-6762 Primary
Bill @ (813) 789-3098 Secondary

BearKiller

Thank you, NASCAR CAMPER.