I run a gravel driveway business and tow a 21k lb gooseneck dump. It's fine with my 2018 F-350 drw 4x4 but that's also my Sunday truck and I don't wanna take it to the quarry. So I've been hauling back roads with a 2004 F-350 and don't like how hot the 6.0 runs. Apparently Ford in its infinite wisdom put the same coolant capacity in all 6.0s and 7.3s from F-250 right up thru F-550. 28.5 quarts, smh. I may be over CGVWR too with the srw.

Another gripe with the 5R110 is no lockup in lower gears and only fair engine braking. I also don't like 8 mpg and needing 3000 rpm to climb even mild grades. I get 10 mpg in the 2018 and can climb any hill at 2000 rpm in manual shift mode. I know, the 6.7 is a beast and it's an unfair comparison. But as we say in Texas, it is what it is. On the other hand, the 6.7 is overly complex, with 2 different cooling circuits and 18 computers on board. I plan to sell it before trouble starts.

So I was looking for a F-550 cc or sc 4x4 with 7.3 and ZF6. Unicorn hunting.
UPDATE But if you look a few posts down, you'll see that no manual tranny F-550 can legally tow my trailer.

Any tips welcome.

It seems that the 450/550 don't have their own forum here on FTE so many of you hang out here?

I drove 3 hours today to see this F-550, a 6.0, against my better instincts. Here's what I found, ugh. https://www.bitchute.com/video/f1UC7u7LmMWs/

 

Thanks to @Just Strokin I found https://www.fleet.ford.com/towing-guides/

This correct info from Ford totally dashes my hopes of using a 7.3 or even a 6.0/ZF6 for my business. Only the 2005-up 6.0/5R110 F-550 can legally tow my dump trailer.

Unless I go to an older F-800, but I've never seen a 4x4 of that yet.
.

 

You have a 21K gooseneck dump trailer. For purposes of the Ford Towing Guide, gooseneck is treated the same as 5th wheel, as far as ratings.



So yes, you CAN use a 7.3L.

Now the next question is 4x4.

Here's a tip: The High Capacity Trailer Tow Package, referenced in footnote 2, otherwise known as RPO 535, is the key enabler of the nearly 3K lb bump in trailer towing capacity.

During this era, Ford only offered RPO 535 in the crew cab 4x2 F-550. Other than the secret ingredients of package 535, the engine, transmission, and gear ratios are the same between 4x2 and 4x4 offerings.

So what are the secret ingredients to 535?

1. Full Synthetic gear lubricant in the Dana 135 rear axle, which otherwise is factory filled with mineral oil (unlike the pickups of the same era). The Dana 135 holds over 3 GALLONS of lubricant, not just 3 quarts, so the cost of filling with synthetic, full synthetic at that, can be significant. It cost me well over $300 in fluid alone to fill the rear axle of my 2000 4x4 F-550 with synthetic... so imagine multiplying that cost per vehicle over an entire production cycle of hundreds of thousands of trucks... and one can see why Ford went with mineral oil for the factory fill. Except for those customers who ordered the High Capacity Trailer Towing Package. You can easily exchange fluid and add this part of the package yourself.

2. Oil to Water automatic transmission cooler. This only applies to 1999-2000 model years, which were not built with OTW transmission coolers... only oil to air coolers. The High Capacity Trailer Tow package had both. By 2001, all Super Duties had both, so this addition would not even be necessary to add to the 2003 models identified in the towing guide photo above.

That's it.

So it all boils down to the rear axle fluid (for the F-550 with the 7.3L engine). If you find an F-550 with a 7.3L and 4R100 automatic, and change the rear axle fluid to full synthetic, you will approximate the same equipment that Ford rated as adequate to tow a 21,500 lb trailer, more or less.

 

Sorry if I wasn't clear enough. 7.3 w/ ZF6 was the goal. Towing heavy with a 4R100 is a big bag of not fun for my use. Sure, it's OK out on the road, but I'm on hilly back roads most of the time.

 

I'm now looking at F650 and F800, avoiding the spendy Cat C7 and its DPF/regen stuff.

 

That towing guide makes me laugh.
The reason the ZF6 is rated lower doesn't have anything to do with the transmission, the stock clutch can't handle the load.
Put a heavy duty clutch in it and the trans will handle it just fine, my does.
This is my 04 F-450 scab 4x4 with ZF6, pay no attention to the badges, the fenders have been swapped.
Trailer is rated for 22k, truck and trailer empty weigh 16k, I normally haul 12-14k on the trailer.
The clutch in it now is a little jerky taking off but manageable, if I ever have it back apart I will probably go with a organic dual disc.

 

That makes sense. My limitation is that I may have to prove on paper the truck's rated capacity by the manufacturer during a roadside inspection. Our local deputy who enforces commercial is so tough that he once wrote his own wife a speeding ticket. He also put his own mother in law in prison. Wait, I just made that part up, but it would be a good place for mine.

I've seen quite a few ZF trucks lose the factory dual-mass flywheel, in pieces, and instead install a LUK solid flywheel and heavy clutch.

Wanna sell your truck?

 

Your deputy wouldn't know what to do with my truck being it's a 04 with 07 coil spring front and a 5.9 Cummins 12 valve under the hood.
I looked at the vin tag on mine, it shows axle weight ratings and the 15k gvw but doesn't have anything pertaining to a max gcvw listed anywhere.
DOT in this area look at axle, tire and gvw ratings for the truck and trailer, which ever is the lesser is what they consider the max gcvw.

Sorry but this truck isn't going anywhere, when it goes it'll be a pile of scrape or at my estate sell.

With you gravel business you may want to consider a single axle dump truck, that'll put you into CDL territory but a medium sized dump truck is easier to maneuver and will handle loads better.
I was looking at getting a dump trailer to pull behind my F-450 until I purchased my 93 F-800 with 8.3 Cummins and air brakes for less than a decent sized dump trailer.

 

Going to look at an F-8000 today with the 5.9 and Eaton 6 speed

 

This is good advice. Especially if you and your father are mechanics and can handle the repairs.

The only issues are the cost of truck licensing, commercial insurance, motor carrier permit, and any applicable commercial driver's licensing requirements... depending on the laws applicable in your state for the weight ratings of the truck you select.

But functionally, a single axle dump will place material easier in most curvy hilly tight turn around situations resurfacing ranch roads.

 

The only thing they can go by is you axle ratings, there is no way for them to know the factory Ford ratings unless they look up your vin. Stay within you rated axle capacities and you will be fine, a ZF6 with a good clutch in a 7.3 F550 will handle that weight.

 

"Legally" ?? Ford does not write the laws here. Ford is concerned with 3 things. 1 Sales 2 Lawsuits and 3 Warrenty claims.
I do Not for a second agree with the ZF6 = low tow capacity.

I have a truck with a ZF5 I bought in 1995. I think it has a bout half a million miles on it. (NOT A JOKE) It has never been rebuilt. It has only had the Throw out bearing sleeve replaced once. It was due to a throw out bearing locking up and killing the sleeve.
any how it is in a 89 F-Superduty (F-450) It is a Rollback Towtruck the 5.13 gears are what I credit to its long life. That and the fact that the driver was also the owner and paid all bills.

 

Sounds like you already need to have a CDL. If your pulling anything over 10,000lbs you have to have one. It does not matter what your pulling it with either, be it a f150 or a f800 if it's over 10,000lbs of tow capacity.

As for your business, I would suggest at a minimum a f650 or bigger. Due to larger brakes more truck weight so trailer doesn't push you around as easily. That's if you want to keep using trailer. But ultimately a single axle dump would be the most efficient for your business.

 

The advantage to a lowboy trailer is consistent tailgating. Done from a few inches off the surface, it usually requires no or minimal back dragging. Sometimes 5 minutes with a rake is all that's needed.

From a tandem dump, 3' or more up in the air, tailgating is an art. And results are variable. More time needed on the tractor. Much more.

Yes, CDL is required from 26,001 lbs CGVW up

 

Not really, spreading depth is all determined by the tailgate opening and speed, depending on the size of the rock your spreading one sets the chains for the tailgate to open a certain amount then select the gear and rpm to get a speed that determines the depth of the rock being spread.
Once the chains are set for the tailgate opening maintaining a steady speed reduces the amount of raking or blade work needed.

Some dump truck operators don't know how to spread or don't care and can make a mess that require a lot of blade work to straighten out.
I have a friend that does most of my spreading, unless there's overhead wires or there's a danger of turning the truck over I hardly ever have to follow up with a blade.