Just got back from another 5000 mile tow with my 17, 5.0, RCSB. 20% of the mileage on the truck has been run up with this trailer on the back and another 20% with my other trailers on the back. On the run over the pass from Yuma in to San Diego the trans temp ran to 224 and did not come down for 30 miles plus on the other side. This is the first time I have seen this slow cooldown and I am hoping it will be the last. I have an AFE trans pan (+7 quarts) coming and it should get installed next week. Has anyone else installed this pan? The B&M adds 3.2 quarts. I am a believer in the more oil is good and I am buying this pan because I got a super deal, $120 back of retail. I may build a windage tray to help control slosh but then I am not racing this truck. Input please. By the way my truck is a bit of an anomaly with a M (16,001# to 19,500#) in the VIN for GVWR. I was talking to a ranger in NM and we figured out why this truck exists. States place special orders all the time with Ford and Dodge. Every year NM Dept of Forestry orders special equipped 4x4s for offroad use and special equipped 4x4s for onroad. Since TDOT has been ordering Fords exclusively I am guessing this, along with the its twin, were unclaimed leftovers from TDOT’s 2017 special order.

 

Two things:

1) 224ºF is not hot for LV fluid. In the workhorse F250, the fan doesn't come on to lower trans temp until 249ºF, and it shuts back off at 246ºF. It's not handled like an emergency, the fan is only engaged at 20%. There are five steps, with the fan not getting to full ape until 265ºF. LV fluid doesn't experience instant degradation until somewhere between 285 and 290ºF.

2) With the transmission relying entirely upon dumping heat into the engine coolant system, your engine and radiator are going to determine the operating range of the transmission. If it was taking the transmission a long time to cool down, it was most likely due to the engine taking a long time to cool down. Maybe you have a blockage in the radiator (easily determined by using a cheap infrared thermometer), or maybe you need the larger radiator for your driving style.

Adding a bigger pan for more fluid will lengthen the life of the oil more than provide additional cooling. Some additional cooling will come from having a larger surface area on the pan, but it's not a striking difference. With more fluid, it will take the transmission a bit longer to heat up during climbs, but also longer to cool off after.

I'd attack the source of heat first. Increasing oil capacity is beneficial, but only doing that is like throwing more water on a fire, but not enough to put it out.

 

49,900miles, no cold spots on the radiator, fans kicking on as needed. I am just uncomfortable with a 224F oil. I may have a slightly restricted radiator but it does not appear so. Most of my fuel stops were pull off, fill up, fire up and leave. Once I got a quick overheat warning caused by the heat soak and then I paid a bit more attention to fire up temps and while the gauge always showed WARM the cool down was instantaneous. This quick recovery leads me to believe the radiator is doing its job. I will be venting my under vehicle covers a bit to force air over the trans cooler on the crossmember and I will check the additional cooler up front, HD cooling option based on GVWR, for bugs but there were very few on the windshield so I do not believe I will find any. Just thought I would ask but as I said before more oil is good. Not just for cooling but also for the ability to carry more contaminants.

 

If you're simply taxing the tranny but everything else looks good, you can always put an oil to air cooler inline with the oil to water cooler.

OEM trans cooler is $55
Mounting bracket is $24
Larger Raptor cooler that fits the same bracket is $58

There's also this little device that's great if you have true cold in winter and want to keep oil from flowing through the oil to air cooler.

Double-check that you don't have a cooler under the bellhousing. 2017 was the switch to 10r80 and I thought also oil to water cooler, but parts sites list the grill mounted transmission cooler until 2019.

 

Time to find some average running temps to figure out what exactly is going on. This truck has the water to oil/air trans cooler on the crossmember and the aux trans cooler out front like I thought. The radiator might be getting a little weak even though I can not prove it at this point. If the trans temp sensor is on the hot side I am most likely fine. If it is on the cool side then I potentially have an issue with engine temp being a touch oil the hot side. Time to figure out where the trans temp sensor is located in the oiling circuit.

 

If the trailer you are pulling is the 15' Starcraft you mention in a previous post, you should be having no problems. You are keeping it below 70 mph I assume, if not, give that a try next time.

 

The trans temp sensor is inside the transmission.

You say you have an oil to water cooling under the transmission, AND an oil to water cooler in front of the radiator? Haven't heard of that, but you say it's a special order truck. Do the lines going to the oil to air cooler look oem (aluminum tubing + rubber hose) or add on (rubber hose only).

 

Bugs may not be too bad now, but over the miles they accumulate. Be prepared to get wet (choose a hot day) and back flush the bugs, dust & dirt out of the cooling fins. I start doing this at 3-4 years vehicle life, and normally annually after that.

 

This truck has the HD towing package. Cooler on the crossmember and cooler out front of the radiator/condenser stack. The medium duty package only gets the cooler on the crossmember. The AFE +7 quart pan is on and it took about 13 quarts to fill it. Went for a test drive and there is no difference in trans temp during normal driving. I am leaning towards a lazy engine thermostat so one is on the way and I will do a complete drain and refill on the cooling system. Stay tuned.

 

Is this what is on your crossmember? I did not know these existed, but don't follow the 5.0 closely. Appears they used a mini oil to water with an oil to air before going full oil to water.