Now that I'm almost settled and having time to read, I find that this 99 F350 King cab dually w/7.3 diesel 4.10 w/16" tires and 4R100 trany 68K miles w/all the bells and whistles, a Mark III..... may not be sufficient.
You will probably be over the weight limits of your truck, but with some mods and careful driving it will get the job done.
The GCVW is 23K, so I'm right on the boarder.
The GCWR of a '99 F-350 DRW is 20,000 pounds, with a "tow rating" for a 4x2 of 13,800 pounds. Notice that in order to tow a 13,800 trailer and stay within the GCWR, the wet and loaded dually must gross less than 6,200 pounds. Ain't gonna happen. Count on a wet and loaded dually weighing around 8,000 pounds, leaving you a 12,000 pound actual tow rating.
It this going to be OK but as slow as a snail?
Your Mobile Suites is going to gross a lot more than 12,000 pounds, even if you always dump all the holding tanks (including fresh water) before you hit the road. So you're not going to win any races. But since you plan to stay west of I-5, with the right mods your rig will do just fine - provided you don't try to climb the Grapevine with that rig.
I've also read that the 4R100 tranys crap out in short but one can buy a HD or supreme rebuild for around 5K. The one I have now shutters between 35 & 45 after it shifts into 3rd.
The first thing to go will be the torque converter, and provided you replace the torque at the first indication of "marbles in a coffee can" before it goes south and takes the tranny with it, then the tranny should last until a bit over 100,000 miles, provided you took excellent care of it and always change the ATF to Mobil 1 every 30k miles. When you do have to replace the tranny, there are three basic choices:
1)Ford OEM 4R100, probably less than $3000, good for another 100,000 miles, provided you never allow it to get over 225° sump temp and change the synthetic ATF every 30k miles.
2) Ford HD4R100, around $4,000, probably good for 200,000 miles provided you never allow it to get over 225° sump temp and change the synthetic ATF every 30k miles.
3) John Wood or BTS bulletproof 4R100, around 4,500 to 5,000, guaranteed for as long as you own the truck if they don't find indications you abused the tranny by overheating it. Mine was a BTS, but John Wood is a lot closer to you in CA.
Note that allowing a tranny shop - even a Ford dealer's tranny shop - to overhaul your tranny is NOT
one of your choices. It's cheaper, but you get what you pay for.
I've looked at the newer 350's and the only difference is they upgraded the 5er towing in 2014 to 22600# from the 13200# in 1999.
You missed a coupla steps up the ladder. In 2005 model year, GCWR went from 20k to 23.5k. In 2011 with the new 6.7L Ford diesel engine, it jumped up to 29,000. In 2013 model year, it was up to 30,500. I haven't looked at the 2014 specs yet.
So is there any difference in the chassis or is just a stronger motor?
There are all sorts of differences. But for GCWR, the big factor is engine power/torque and axle ratio.
So, am I screwed or can I just crawl along at my own pace?
You can spend some money and turn your sows' ear into a silk purse. Well, maybe not as good as a silk purse, but certainly better than a sow's ear. I'll summarize the mods you need, then go into more detail.
1. Gauges. If you increase engine power even a tiny bit, you must have good gauges to monitor your temps. Heat is the killer, and you don't want a dead dually. But without gauges, you're flying blind.
2. Intake. The stock intake on a '99 and even a '99.5 was awful. Replace it with a "cold air intake".
3. Exhaust. The stock exhaust was restrictive. Plus if it hasn't already been replaced, it's probably stopped up after 15 years.
One result of better intake and exhaust is faster speeds or heavier loads or steeper grades without exceeding the 1,250° pre-turbo EGT red line. You can "drive by the gauges" and maintain EGT between about 1200° and 1250° the same way you maintain a constant speed with the go pedal.
4. Tranny cooling. Look closely at your tranny cooling system. If the cooler lines run into
the radiator, then your truck had the Ford warranty fix that is a lot better than the original oil-to-air (OTA) heat exchanger. But if the tranny cooler lines go around
the radiator and into the OTA cooler, then you definitely need a lot more tranny cooling capacity.
5. Engine power. The 7.3L can handle a lot more horses than the factory settings, without reducing longevity or reliability. You can go hog wild with mods to increase power and torque, or you can do what I did and simply use a mild towing tune with gauges to add about 80 ponies. I made one long trip without my towing tune, and as soon as I got home I ordered a new towing tune. It's just so much more pleasant towing with around 300 horses instead of 230.
1. Gauges. You need three aftermarket gauges
- pyrometer with a top mark over 1,250° but not much over 1,500°. Be certain the thermocouple (sender) is installed in the exhaust manifold or the up pipe to the turbo. That's called pre-turbo. Never allow more than 1,250° pre-turbo EGT.
- turbo boost gauge, with the max on the dial of about 30 PSI. Never allow more than 25 PSI.
- Tranny temp gauge, with the sender installed in the pressure port on the driver's side of the 4R100. Up to about 210 is normal. 210° to 225° is hot. The red line is 225°. Don't allow it to go over 225 unless you can see the top of the pass right in front of you. Be sure the bottom peg on the gauge is 100° and not 140°. With 140 as the bottom peg, you'll not see the gauge move in the wintertime, so you'll wonder if it's working.
My choice is ISSPRO gauges from Diesel Performance at DieselManor, Inc.
2. Intake. Best is the Ford Severe Duty Air Induction System (AIS) for a 7.3L. But Ford no nonger makes it, so you have to find a diesel truck supplier that still has some made by the original supplier, Donaldson. Here's one: Ford AIS Severe Duty Intake System 98.5-03 7.3L Powerstroke FA-1759
3. Exhaust. Tear it all out and replace it with a turbo-back 4"performance exhaust system. Here's a good one, except get the one for a Ford and not for a Dodge. MBRP 4" Turbo Back Exhaust-Single Outlet 04.5-07 5.9L Dodge Cummins S6126409
4. Tranny cooling. Ford learned their lesson with the inadequate tranny cooling system on the 7.3L/4R100. They fixed it right with the 6.0L/5R110. So your mod is to replace the dinky little OTA cooler (heat exchanger) with the much bigger one from a 6.0L. Search on TheDieselStop.com and you'll find instrutions for how to connect the 3/8th lines to the 1/2" cooler connections. You can buy the 6.0L cooler fron any Ford parts counter, and at a discount on the internet. You want the 26-row cooler. That's the newer one and more efficient than the older costlier 31 row cooler: Here's one source: AutoNation Ford White Bear Lake Parts (previously Tousley Ford Parts)
5. Engine power. You need a 60HP or maybe an 80HP towing tune. At least three ways to get it:
1) flash the PCM with the towing tune
2) install a multi-position chip that has the right tune(s) on it
3) install a "programmer" or tuner black box that includes your towing tune.
My choice? Go with a chip that includes 60-tow, 80-tow, decel (exhaust brake), the best of the OEM tunes, and maybe one tune for acting stupid on a Saturday night (but not more than about 120 HP). I really liked my 80-tow tine from DP-Tuner, so that's probably where I would go for the new chip. Diesel tuning products for Ford PowerStroke
- note that DP-Tuner can also flash your PCM or sell you a programmer that includes the tunes you want. (But you cannot have a decel tune on a programmer. Decel requires you to switch into decel tune at the top of the pass and switch back to your towing tune at the bottom of the pass. But it takes a coupla minutes to change tunes on a programmer, whereas on a properly set up chip you can "switch on the fly".