Sorry this is long but I feel I have to relate the whole story. I have a 2001 F350 DRW truck w/7.3 (bought by me 2003) and a 2000 F250 V10 (bought 2005). Trucks now have 80,000/120,00 miles. No known major work ever done to either. Both with basically the same AT. Both have gooseneck hitches, and I occasionally pull a tandem dually gooseneck, with my 16,000lb backhoe/loader. I have never had any problems with either truck (except an engine heating issue on the 7.3 that was found to be a faulty fan clutch). The trailer was pulled by both trucks in summer weather over mountain roads, pulling grades at full power - no problems. A couple weeks ago I loaded an off road vehicle (about half the weight of the backhoe) on the gooseneck and was off to a spot about 300 miles away with the 7.3. The road was hilly but nothing unusual (grades were steep but short). I never made it. While pulling a hill it stopped going and I got out - oil was running out of the bell housing. I managed to park it off the road and got a ride to a town about 30 miles away and called for a tow. When we got back to it the tow driver said he hadn't been told about the gooseneck trailer and he couldn't handle it. As a long shot, I had bought a gallon jug of ATF while in town. Long story short - added the fluid and it pulled well enough to get itself and the empty gooseneck back to town (No leaks noted). The vehicle on the trailer was driven back to town separately. However, after filling the tranny and hooking up, there was no way it would pull the loaded trailer home. So I left the trailer there and drove the truck 300 miles home on the highway. It was OK once you got up to 50-60mph, but starting out you had to be careful as it would shudder (reverse was OK). Once back I got in the F250 to go retrieve the trailer. Hooked on and started home on the highway. No problems at first but after 50 miles or so I started noticing clouds of smoke when pulling a grade (the V10 has the exhaust crossover near the bell housing and the same thing was happening as with the other truck - but this time the ATF that was coming out was burning). I did get it home - but I had to nurse it very slow and easy over any grades.
This experience has been absolutely unbelievable in the context that here are two trucks, similarly powered failing to pull the same trailer at the same time, there having never been any problems or leaks with the trannies on either (I had changed fluid and filter on both after I bought them). And double especially since they had handled much heavier loads in the past with no problems. There are no indications of fluid cooler problems (the trucks both run cool on the gauges). I could understand this if there had been extreme temperatures or other severe conditions present - but there weren't. I just don't know what to do.

 

For one ting you are over weight, especially if the hoe alone is 16K. 2001 is the year that they used the infamous one-way "diode clutch" which is prone to failure - in second gear I believe. The trans in your V-10 is a lighter duty version of the 4R100. Don't know if year modle makes a difference here with the clutch situation. Hopefully Mark K. will be along to correct any mis-information.

 

Correct, but totally irrelevant. That won't make the trans overheat or leak.

No it isn't. It's the same trans with a different bolt pattern to mate to the V10.

The problem is that the torque converter got too hot, which caused the seal to leak. Once it cools the seal usually works fine again.

I assume this is a different trailer than the one you normally tow? If so, I suspect something is wrong with the wiring on the trailer, which causes the PCM to think the brake lights are on (maybe they are on?) and that keeps the torque converter unlocked. An unlocked converter makes a HUGE amount of heat.

 

"Nobody has made MERCON since 2006. MERCON V replaced MERCON. Get over it."


You've said it so many times, they're gonna put it on your Tombstone......

 

It's gonna save a lot time on the forums. Now all he needs to type is, "See my signature."

 

I agree 100% with Mark. Happen to me on the beach. I would think your converter now needs replacing at least. Only because of all the weight you've been hauling over time. I drove mine another couple years after this happen, with no more leaks before something else caused me to replace.

 

I wouldn't expect the converter to be damaged.

 

So Mark, what damage do you reckon there would be? I'm new here and trying to learn all I can.

 

I wouldn't expect anything to be damaged. Why would something be damaged?

 

My damage question...at what point in overheating does the torque converter become damaged?

 

Did you check and make sure the brakes weren't dragging on the trailer?

 

A couple of questions:

1 - How much does the empty trailer weigh? I'm guessing 8k or so, so you're pulling roughly 24k? And grossing about 33k with the dually?

So you obviously know you're WAY over legal weight, WAY past what the truck was designed to haul, and well past what many people with much more towing and pulling experience than you or I, would even consider to be safe. I'm shocked that you haven't had any problems yet, especially transmission.

2 - What upgrades have you done to the truck and transmission? You said you had gauges, but you didn't say anything about a bigger cooler or anything else.

3 - When you said the gauges said it was running cool, what does that mean? Does your transmission temp gauge have numbers on it, or does it just say cool/hot?

Generally when these things overheat, the seal temporarily fails and it pukes fluid out of the bellhousing. Once it cools back off, the seal does it job again and everything is back to normal. If you have symptoms AFTER that, then, you can start looking for signs of damage.

But bottom line is that you are simply towing too much weight. Get an F-550 if you need to haul a 16k loader.

 

It is the same trailer I have always pulled. What about the brake lights? I have electric brake controllers on both trucks - the trailer brakes work fine on both. The brakes on the trailer are activated by pressing on the brake pedal and turning on the brake lights. If the brake lights (and therefore the trailer brakes) were on, you couldn't pull the trailer with a Kenworth.

 

Yes - a tandem dually trailer has powerful electric brakes and any drag would root you to the spot. It rolls free without brake actuation.

 

Everything is well within weight guidelines. Truck weighs 7000 empty, plus 4000 load on gooseneck hitch, or 11000 out of max 12000 GVW. Trailer weighs 6000 empty, plus 16000 tractor or 22000 out of max GVW 24000. I have virtually never seen an F550 on the road - everyone pulls their goosenecks with F350s or even F250s. Kind of ridiculous to get an F550 which after all has the same engine and transmission. It may have different tires and wheels - but no tire or suspension component is loaded beyond its rating, and the trailer has its own separate brakes.
When I say it runs cool - the water temperature gauge stays in the lower part of its range. I do not have a separate transmission temp gauge - the transmission oil is cooled through a radiator heat exchanger.