[joehelf]

I have a '99 F350 7.3 dually with 111K miles. I pulled a 15K fifth wheel camper 300 miles from home and then back 5 days later. (I went fishing for Walleye in Lake Erie)
The truck did great! I would turn off the Overdrive on the gear shift when starting out from a slow move. Then once I was up around 55 mph I would allow the Overdrive to come back on and go down the highway just cruising. The trip went great until I pulled within a mile of my home.
As I turned off the highway on to my road and then to my drive I noticed transmission fluid pouring out from underneath the truck.
I got it home and parked it. I lifted the camper off the back end and let it sit for two days. Then I moved it to the barn. I'm gonna tackle looking at what may have happened. Maybe a seal blew? Maybe a line blew off? Maybe lost my torque converter? I was able to restart the truck and put it in the barn which means I had to drive it about 500 ft. in order to look at it. I don't know how much damage I might have done. I did go back down the road to see if I could see the trail of fluid and I definitely found where it started. I followed the line of transmission fluid all the way to where I was sitting when I put it in Park. But 2 days later I was able to drive it into the barn.
Do you think I cooked my tranny? Does anyone pull a trailer and ever use their Overdrive?

 

[67dart/cuda]

I have a '99 F350 7.3 dually with 111K miles. I pulled a 15K fifth wheel camper 300 miles from home and then back 5 days later. (I went fishing for Walleye in Lake Erie)
The truck did great! I would turn off the Overdrive on the gear shift when starting out from a slow move. Then once I was up around 55 mph I would allow the Overdrive to come back on and go down the highway just cruising. The trip went great until I pulled within a mile of my home.
As I turned off the highway on to my road and then to my drive I noticed transmission fluid pouring out from underneath the truck.
I got it home and parked it. I lifted the camper off the back end and let it sit for two days. Then I moved it to the barn. I'm gonna tackle looking at what may have happened. Maybe a seal blew? Maybe a line blew off? Maybe lost my torque converter? I was able to restart the truck and put it in the barn which means I had to drive it about 500 ft. in order to look at it. I don't know how much damage I might have done. I did go back down the road to see if I could see the trail of fluid and I definitely found where it started. I followed the line of transmission fluid all the way to where I was sitting when I put it in Park. But 2 days later I was able to drive it into the barn.
Do you think I cooked my tranny? Does anyone pull a trailer and ever use their Overdrive?

I pull a 24’ enclosed car trailer loaded with my race car and spare parts and tools and I will go down the hwy at 65-70 mph with overdrive on.
I have upgraded the transmission cooler to a larger Mishimoto cooler, a deeper aluminum pan to increase capacity and had John Woods go through the valve body. It works very well. My truck is all stock except for a 4” MBPR stainless exhaust. The truck has just under 55,000 miles.

 

[michael67]

The rubber lines and clamps are approaching a quarter century if you've never replaced them - I'd check those first. Also, make sure it's transmission fluid and not power steering fluid.

 

[JustAFenceBuilder]

I pull my dozer and it, and it’s trailer weigh 19,800. These trucks have no issue moving weight.

No issues towing in OD with my old pseudo built transmission that came in the truck and it’s a rock star with my BTS. Even pulling a 5th wheel with a rowdy head wind. No problems.

I’d check and find the leak. Power steering fluid is very similar to ATF, and in some trucks it’s the same stuff. However, Running an auto trans out of fluid once isn’t a death sentence.

 

[Gnathv]

Your 4R100 has a vent on top, if the transmission got too hot it will dump fluid out the vent.

 

[BionicArcher]

I’ve pulled roughy 20,000 as doubles, no problems

 

[ziggystardust]

I have a '99 F350 7.3 dually with 111K miles. I pulled a 15K fifth wheel camper 300 miles from home and then back 5 days later. (I went fishing for Walleye in Lake Erie)
The truck did great! I would turn off the Overdrive on the gear shift when starting out from a slow move. Then once I was up around 55 mph I would allow the Overdrive to come back on and go down the highway just cruising. The trip went great until I pulled within a mile of my home.
As I turned off the highway on to my road and then to my drive I noticed transmission fluid pouring out from underneath the truck.
I got it home and parked it. I lifted the camper off the back end and let it sit for two days. Then I moved it to the barn. I'm gonna tackle looking at what may have happened. Maybe a seal blew? Maybe a line blew off? Maybe lost my torque converter? I was able to restart the truck and put it in the barn which means I had to drive it about 500 ft. in order to look at it. I don't know how much damage I might have done. I did go back down the road to see if I could see the trail of fluid and I definitely found where it started. I followed the line of transmission fluid all the way to where I was sitting when I put it in Park. But 2 days later I was able to drive it into the barn.
Do you think I cooked my tranny? Does anyone pull a trailer and ever use their Overdrive?

I run a 99 F350 DRW for hotshot. I've grossed as high as 31,600. No, I don't turn off the overdrive, not ever. I find the transmission runs hotter when you do.

But as for your ATF dumping out, it's the front seal on your 4R100 transmission. They originally came with a gray one that when the fluid got to 250 degrees, it would deform and puke out a bunch of ATF. you will have to pull the transmission, slide off the torque converter and the seal is right there on the input shaft. Get one from the Ford dealer, it's only around $20. Easy to replace...if you don't account for pulling a transmission that weighs about 275 lbs. Would cost you nearly $1000 for a transmission shop to do it.

And if you haven't already done it, I highly recommend you install a 6.0 sized transmission cooler. The link below is a YouTube video of me installing one, and all the parts are listed in the description.

YouTube Video of me installing 6.0 cooler

 

[joehelf]

Wow! I appreciate all of your comments. So here's what I've done so far. I put the truck up on jack stands and got underneath to see if I could tell where the leak came from. No where was wet nor any residual fluid hanging around. So, I pulled the torque cover off and checked inside there but it did not look bad either. Although it was wet with new looking trans fluid. A friend's dad told me to check the fluid level with it running and warmed up. I did but could not see it on the stick. So I began filling it with fluid. It was 4 quarts low when I finished filling it back up. My friend taught me a cool trick. He said to take the dipstick and dust it with AJAX. The AJAX will let me see the exact place where the fluid is resting and won't harm the trans because it doesn't get into the fluid it just sticks to the stick long enough to get wet. When you pull it out and check the level just wipe it down. After 4 quarts I was satisfied it was enough. So the next day I drove it to work. A 35 mile trek. No one drop of fluid! All the way to work and back home. No leaks nor drips anywhere. Now I think the seal behind the torque converter makes the most sense of all that I've read and I might tackle that in a few days. But I think the first thing I will do is load up the 5th wheel and take a short trip just to see if it happens again. Since reading y'alls comments I wonder if it will take me loading the truck down again before I'll notice any leakage? Just wondering since the level is fine after only one trip to work and back.
Thanks again, I'll keep reading and I'll let ya know how it goes.

 

[ziggystardust]

Wow! I appreciate all of your comments. So here's what I've done so far. I put the truck up on jack stands and got underneath to see if I could tell where the leak came from. No where was wet nor any residual fluid hanging around. So, I pulled the torque cover off and checked inside there but it did not look bad either. Although it was wet with new looking trans fluid. A friend's dad told me to check the fluid level with it running and warmed up. I did but could not see it on the stick. So I began filling it with fluid. It was 4 quarts low when I finished filling it back up. My friend taught me a cool trick. He said to take the dipstick and dust it with AJAX. The AJAX will let me see the exact place where the fluid is resting and won't harm the trans because it doesn't get into the fluid it just sticks to the stick long enough to get wet. When you pull it out and check the level just wipe it down. After 4 quarts I was satisfied it was enough. So the next day I drove it to work. A 35 mile trek. No one drop of fluid! All the way to work and back home. No leaks nor drips anywhere. Now I think the seal behind the torque converter makes the most sense of all that I've read and I might tackle that in a few days. But I think the first thing I will do is load up the 5th wheel and take a short trip just to see if it happens again. Since reading y'alls comments I wonder if it will take me loading the truck down again before I'll notice any leakage? Just wondering since the level is fine after only one trip to work and back.
Thanks again, I'll keep reading and I'll let ya know how it goes.

I should have added this the other day, but I got busy.

After that seal pukes and then cools off, it typically seals back up and runs ok. So you are doing the exact right thing. Just be sure to have plenty of ATF with you so you don't get stranded. Let it cool off, top it off and make it home safely.

I would still recommend adding a 6.0 cooler if you are hauling heavy.

I thought I had the same issue, and was busy so I took my truck to a very good transmission shop. Well, they were short handed and didn't have time to do it for me. So I pulled the tranny and took it to them. They changed the seal (for $20) and I put it back in. STILL leaking! So I took it back apart thinking I damaged the seal when I installed the torque converter and nope, the seal was fine. Did a little more checking and found a leak on my torque converter.

 

[joehelf]

I should have added this the other day, but I got busy.

After that seal pukes and then cools off, it typically seals back up and runs ok. So you are doing the exact right thing. Just be sure to have plenty of ATF with you so you don't get stranded. Let it cool off, top it off and make it home safely.

I would still recommend adding a 6.0 cooler if you are hauling heavy.

I thought I had the same issue, and was busy so I took my truck to a very good transmission shop. Well, they were short handed and didn't have time to do it for me. So I pulled the tranny and took it to them. They changed the seal (for $20) and I put it back in. STILL leaking! So I took it back apart thinking I damaged the seal when I installed the torque converter and nope, the seal was fine. Did a little more checking and found a leak on my torque converter.

I will do precisely that! I will keep a couple of quarts with me for the insurance until I get the chance to change the seal and install the 6.0 cooler.
This website is the beast! Thanks for the video too. It made sense totally.

 

[ziggystardust]

I will do precisely that! I will keep a couple of quarts with me for the insurance until I get the chance to change the seal and install the 6.0 cooler.
This website is the beast! Thanks for the video too. It made sense totally.

In the video I mention that this was the second time doing it which is why I knew all the steps. I pointed the camera out to the wrecked red truck where I first installed the cooler.

I'm also on the Ford Truck Enthusiasts and have met a great bunch of guys who are a great help!

 

[joehelf]

In the video I mention that this was the second time doing it which is why I knew all the steps. I pointed the camera out to the wrecked red truck where I first installed the cooler.

I'm also on the Ford Truck Enthusiasts and have met a great bunch of guys who are a great help!

So, I noticed you were only using normal hose clamps on the hoses. I take it the pressure on the trans fluid is not that much? Again, I'm kind of new to this transmission and the idea of changing the cooler. As of a matter of fact I haven't looked at mine yet to see what kind of cooler I have. LOL

 

[ziggystardust]

Yes, the pressure is not very high. The PCM commands different pressures for controlling the shifts in different situations.

The pressure port on the driver's side is where you can measure that pressure for troubleshooting and that's where I measure the transmission fluid temperature which is much higher than you read from the PCM. The PCM gets the fluid temperature from a sensor in the solenoid pack and reflects the temperature in the sump after it's been cooled.