This is probably not the place for this post but I'm curious if anyone has experienced this. My tow vehicle is a 2002 Ford 250, 7.3 Powerstroke diesel. I'm towing a 7000 travel trailer. The problem is sometimes, not always, I blow transmission fluid while towing and it leaks out when I stop. The transmission is not overheating, if the gauge is working correctly. I have had the transmission serviced regularly and talked to several dealership service reps about this and they all say nothing appears to be wrong. The leak seemed to have stopped for a period of time and then it started back again today. I'm not positive but I think it has always done this in the hot summer months. I camp more in the cooler months so that may explain the intermittent problem. Any ideas what I'm dealing with before I head to ANOTHER transmission shop?

First off leaking from where ? Vent tube? Maybe your TC is not locking up. Hard to determine without knowing where the leak is.

You'll be much more likely to get better help hereIt's where many knowledgeable Ford owners and pros post.

It may be that when you tow, the trans fluid get very hot, even though your temps read normal. Some fluids will start to foam and leak out the vent. Is your fluid top grade? Is the cooler blocked with bugs and dirt? If the leak appears near "Bell Housing" case, more than likely, vent. Most often if the TC or front pump seal is the problem, it will leak all the time. I suggest changing trans fluid and filter to highest grade. Ford does require a different fluid. You may also have to add a better/bigger trans cooler.

My son has a 2002 F-350 dually 7.3 diesel. His transmission only leaks when he backs the trailer up a hill after towing home on a hot day--I believe it is the rear seal. That is the famous Ford 4R100 transmission which is not famous for reliability, as opposed to the 7.3 engine. Other son lost his at 100,000 mi. First son decided that it was cheaper to fill the fluid occasionally than pay for a complete rebuild before it goes out completely--has been running this way for over 50,000 mi. Most Ford transmissions are not hurt by overfilling--they just blow it out the breather--still best to properly fill. As said above, need to find out where the fluid is coming out. Best advice would come from an independent, non-chain, transmission shop.

Transmission leaks when towing | Good Sam Community

23 Replies

marcsbigfoot20b
Explorer
Jul 06, 2017
SidecarFlip wrote:
marcsbigfoot20b27 wrote:
SidecarFlip wrote:
I checked out the 6.0 cooler, it's huge. Between my air to air, charge air cooler and that trans cooler, I'd think the airflow to the radiator would be minimal. It's quite large. My Hayden is pretty big (or so I though at least) until I looked at the 6.0 cooler.

It's this big......

I may get one. Rock Auto has them at a reasonable price.

Thats where I got mine, best price hands down for new.

My PHP Hydra tunes made my dog slow soft shifting trans shift like it should have from the factory.
SidecarFlip
Explorer III
Jul 06, 2017
lenr wrote:
A lot of heat comes from an unlocked torque converter which happens a lot on Ford 4 speed transmissions towing and running in 4th gear. Cheap solution is lock out OD, but that spins the engine pretty fast. Have read that Banks makes a plug in controller for this transmission that increases shift points and keeps the converter locked more of the time all of which reduces heat. Just another option.

I have one on my E4OD. It increases line pressure, reprogrrams the shift points and locks the torque converter sooner and keeps it locked longer. Downside is it shifts much harder, you have to be careful on the 1-2 upshift and take you foot of the fuel pedal when it shifts which isn't a big annoyance but is necessary.

My box was rebuilt with metallic clutch plates and a modified valve body to begin with so my shifts may be 'harder' that the average box.

It's an easy install too.... watched them do it, took about 10 minutes.

The harder it shifts the less slippage there is, the less heat produced.

My box was refitted by Ford SVO along with the full Banks Kit (ata-quick spool turbo, chip, K&N tuned intake. They also installed a Detroit Tru-Trak locker in the back replacing the Ford limited slip and an ARB air actuated locker in the front. I tossed the Warn/Ford lockout hubs for a set of Mile Markers.
SidecarFlip
Explorer III
Jul 06, 2017
marcsbigfoot20b27 wrote:
SidecarFlip wrote:
I checked out the 6.0 cooler, it's huge. Between my air to air, charge air cooler and that trans cooler, I'd think the airflow to the radiator would be minimal. It's quite large. My Hayden is pretty big (or so I though at least) until I looked at the 6.0 cooler.

It's this big......

I may get one. Rock Auto has them at a reasonable price.
lenr
Explorer III
Jul 06, 2017
A lot of heat comes from an unlocked torque converter which happens a lot on Ford 4 speed transmissions towing and running in 4th gear. Cheap solution is lock out OD, but that spins the engine pretty fast. Have read that Banks makes a plug in controller for this transmission that increases shift points and keeps the converter locked more of the time all of which reduces heat. Just another option.
Sportsmen
Explorer II
Jul 06, 2017
I had the same problem on a '94 F150 w/351 .. problem was a leaking front seal that only leaked when towing our 5500 lb. TT. Had the seal replaced and it never happened again. Ford guy says that it was a known problem with that particular transmission after a certain mileage . Don't remember any more details than that....
Passin_Thru
Explorer
Jul 06, 2017
Don't know on a Ford but Chevy uses copper swedged to rubber cooler hoses that leak. I bought Parker Hoses and haven't seen oil on the drive since.
marcsbigfoot20b
Explorer
Jul 05, 2017
SidecarFlip wrote:
I checked out the 6.0 cooler, it's huge. Between my air to air, charge air cooler and that trans cooler, I'd think the airflow to the radiator would be minimal. It's quite large. My Hayden is pretty big (or so I though at least) until I looked at the 6.0 cooler.

It's this big......
SidecarFlip
Explorer III
Jul 05, 2017
I checked out the 6.0 cooler, it's huge. Between my air to air, charge air cooler and that trans cooler, I'd think the airflow to the radiator would be minimal. It's quite large. My Hayden is pretty big (or so I though at least) until I looked at the 6.0 cooler.
rockhillmanor
Explorer II
Jul 05, 2017
Had it happen to me once on an extremely tough grade.

Thought oh there goes my Trans.

Come to find out on mine, which is a Ford V-10, can't speak for other models. There is an OEM overflow valve. If the Trans gets to hot and starts to overheat it spits it out the relief valve.

I filled it back up with trans fluid and continued to drive it for 10 more years and no problems.
SidecarFlip
Explorer III
Jul 05, 2017
marcsbigfoot20b27 wrote:
SidecarFlip wrote:
First thing I did was landfill the stock transmission cooler on my F350 and replace it with a Hayden 12 pass swirl cool cooler, then I landfilled the stock sheet metal transmission pan and replaced it with a cast aluminum, finned B&M deep sump pan that adds an additional 4 quart capacity. The B&M pan comes with a temp sending boss cast in.

None of the FoMoCo factory cooler are worth much and a slush boxes main killer is heat and foaming fluid. My box never exceeds 210 degrees, no matter how hard I'm pulling in 2 or 4 wheel drive in any range, on road or off road.

The B&M pan makes fluid changes super easy too. My fluid gets changed every fall no matter how many miles I drive. Every 2nd year the pan gets dropped and a new filter installed (with the fluid change). Dexron Mercon V comes in 5 gallon pails btw.

Try the 6.0 Ford trans cooler in a 31-33 row. I never see more than 170 EVER even in Phoenix at 115 degrees towing 7000 lbs up big grades at full throttle 70mph.
The 6.0 cooler is HUGE.

Never checked one out. When I installed the Hayden, the 6.0 wasn't around. I installed it (or should I say Ford SVO-Dearborn) installed it in the truck in 1998 along with the B&M pan, metallic clutch plates, high stall sintered converter and a bunch of other stuff like lockers front and rear, extreme duty universals and a full air-to air Banks kit and chip. At the time, my BIL was one of the head men at SVO. he's since moved on to transmission engineering, he designed the current 10 speed that is coming out in the new 150 pickup trucks.

Fine the way it is and no issues. I just keep the juice changed and the K&N tuned intake filter clean. 5-40 Rotella and the big Motorcraft filter. How about 390 to the rear wheels at 60 mph locked out of OD. It's a cooker and smokes like a freight train. I just keep a close eye on the pyrometer when lugging it and the boost is up around 30 psi.