Any reason to have concerns towing near/at the limit with a V10/4R100 combo in a '00 F350 SC 4x4 3.73 cab & chassis with just under 100k on it? Assume proper maintenance, good brakes on all axles and a driver that is in no hurry. Transmission concerns? It will probably get airbags and RS 9000 shocks in back, towing a low-profile 34' enclosed gooseneck. Guesstimating 10k.

 

We're pulling a 7K TH with a 2002 6.8L Excur 4R100 118k.
I would recommend upgrading the trans cooler to the one used with the 5R110W trans (2003).
The Dorman 918-216 (Amazon $192) is a replacement for the Ford version of the cooler.
It is over 3 times the size of the stock cooler and uses 1/2" tubes.
I think it will bolt in and need 3/8" x 1/2" hose adapters.
It really keeps the trans oil temps under control.
I actually run a large flat plate after the Dorman and a filter.
Also, take a look at the 2008 OEM differential cover (Amazon $59).
Ford would not have started using these without good reason.
I tapped a flat spot on the lower corner to add a drain plug.

 

How are your transmission temperature's? Plugs been changed? Do you have a Scangauge or something to monitor with? I also carry an extra COP, Denso makes the Motorcraft COP's and can be found on Rock-auto for far less.

I recently upgraded my radiator to help cool the transmission as the OE setup did not flow through the radiator, the later versions do. If you need the part numbers I have a thread which you can find under my profile.

 

16year old vehicle towing at max capacity..? I wouldn't do it much.

How long are your trips? How frequent?

 

Dad's 00 F250 v10 had 70K on it 10 years ago when he got it and now has 170K. I personally wouldn't hesitate to tow the same trailer with his truck any distance without notice but I've also done all of the maintenance (other then oil, Dad does that every 4K) and know the truck like the back of my hand.

 

Nothing to do with towing, but have the spark plugs ever been changed?
If the plugs have not been changed I would do so soon.
At the very least check the torque.
Ours blew the #3 plug at 108k.
The passenger side plugs on ours were a bit loose, driver's side were fine.
When the plugs work loose in our 4 thread heads there's only a couple turns left before it goes.

 

Good call on the spark plugs, personally I recommend bumping up the torque on the plugs over the the factory recommendation to avoid future issues.... The exact torque spec is escaping my mind but 50% over seems correct .... Dad had several loose spark plugs at 70K as well as my Mustang's 4.6 at 90K and both still have the factory threads for the plugs.

 

Just curious, do you remember which side had loose plugs?
It seems to me I've read about more plugs blowing out on bank 1.
The lowest miles I've read about was 68k blowing a plug.
I've been changing at 50k, checking torque one more time at 10k and have had no more problems on our 2002 6.8L & 2003 5.4L.

Bentley_Coop actually asked about the plugs first.
The trans temps can't really be read on our idiot gauges so you do need a Scangauge or add a trans temp gauge.
The Koso gauge at Amazon has a nice small rectangular readout which fits on the dash easily.
Ford actually deleted the radiator tank trans cooler on some 2000 models.
Adding a large stacked plate cooler with 1/2" ports would provide more cooling than the stock radiator cooler so a new radiator is not needed to gain adequate trans oil cooling.
Our 2003 Exped 5.4L the radiator cooler became clogged so I bypassed it, added a second stacked plated cooler and the temps are lower than before.

 

Other than way underpowered. I was always amazed that our 1999 f350 dually w/ 4.10s was such a slug. Did headers, borla exhaust, etc which didnt help. In subsequent years they became pretty powerful however.

 

Some good advice above on keeping the plugs tight and fresh. Make sure that '00 has the trans cooler in the radiator like was mentioned and since you are out West where the mountains are bigger the larger 6.0 trans cooler would be nice upgrade. And absolutely get some way to read the actual trans temp, ScanGauge, smartphone app or stand alone gauge.
The 3.73 gears on that rig are going to suck running at that weight in the mountains, consider swapping to deeper gears that will get you to at least a 4.30 effective ratio (effective ratio calculated for over stock sized tires). The 3.73s will get you over the mountains but you will have plenty of time to enjoy the view on the way up.
Look into some custom tunes from 5Star Tuning, they do wake these motors up a little and greatly improve the trans performance.
Our '05 EX with the 2V V-10/4R100 serves as our dedicated tow rig for our 11,000lb TT, we pull 3k - 6k miles a year all over the East with very good performance. The gear swap from the stock 3.73s to the 4.88 (4.39 effective due to the 35" tires) was the single biggest towing and performance mod I've made. The custom tunes and exhaust work both made improvements too but as much as the deeper gears.
Our rig has 110k miles right now and next year it will be 12 years old and we are already planning long tow trips up through Canada, I don't have any age based concerns with this and we plan to keep the current setup and typical usage for another 8 years.

 

I have to mention, add a transmission temperature gauge with it's own sensor right into the side of the 4R100. Keep it under 220 I think - Mark would know more: @Mark Kovalsky

 

With the sensor in the port on the side of the trans you can run as high as 220°F all day long with no problem. You can go as high as 250°F for no more than a half hour at a time.

 

I don't mind going slow up hills, and the truck is moving to FL., so no worries about big grades after we make it out of WY. I have an OBD II scanner that will show all the parameters that the truck can provide. Does the trans temp show up with OBD II, or is a stand-alone gauge needed? Definitely will add a bigger trans cooler to it, synthetic lube in the diff.

 

Thanks for chiming in Mark!

I'm not so sure there IS a PCM PID for the tranny temp on the early 4R100's. Or any of them, actually.

 

Do you have any idea what the temp rise can be thru the trans under heavy load?
If the fluid temp is 150 deg going into the trans around what temp at a sensor in a port on the side of the trans might be seen?
There must be a trans fluid temp sensor somewhere to drive the dash gauge.
Is the dash gauge temp sensor internal or on the side of trans?