I have 2000 250 SD V10 with 4R100 tranny. I am towing at the limits of the truck (16500 Combined, 8700 GVW) and have installed an AutoMeter tranny temp gauge. The sensor is located on the drive side a few inches in front of the shift lever and about 1/4 to 1/2 inch above the pan.

My Ford service guys tells me 180 degrees is it. I read on a Diesel Forum that 250 degress is the temperature to start backing off. That is quite a range and I am not sure if either number is correct, 180 sounds very conservative, 250 sounds pretty high.

Any suggestions and comments?

Thanks,

 

myotis

Every test and all the information I can find suggests that between 150 and 200 is the sweet spot for good lube and long life.

Most of the graphs show that around 208 to 220F the lube starts to oxidize and the long term usefulness is gone but it still has lubrication ability... every thing above 220F starts to cause the oxidization to form crystals or granules around the suspended debris and the lube becomes abrasive...obvious conclusion by now.....


So over 208F for any amount of time and you need more frequent changes...

Any temps above 220F time to think aux cooler and immediate change.

The full synthetic makers argue this point but not one of them will warranty your trans if you do use their product...enough said!

 

Dear Fredvon4:

GREAT response. Being a (retired) high-tech engineer I LOVE data. Could you please point me to website[s] where I can find test and graphs about this, just to satisfay my engineering curiosity :-).

Thanks agin,

Wolfgang

 

In all my years of RVing and towing I've always been told, and been of the opinion that over 220 is bad ju-ju. Fred just qualified that belief, 250 is that 'burnt' smell and loss of lubricity which will let parts start self destructing. There is however different points to measure tranny temp, and pressure can show incorrect readings. Maybe Fred has some insight into this and where to install the temp gauge for correct readings. If I had tranny temps that high even for a second I'd have a total tranny fluid change. Not just dropping the pan, which dumps maybe 5-7 quarts out, but a complete change with a machine. Synthetic fluid will take more heat but 250 is still darned hot, good luck, Ken

 

Here's a guide on transmission temperatures. My sensor is in the port above the pan on the driver's side front. My transmission fluid is changed every 24 months. I get a 5-gallon bucket of O'Reily's Mercon and use every bit of it. The bucket is handy for taking the old fluid back for recycling.

http://www.findarticles.com/p/articl...23/ai_n8688053

Transmission Approximate
Oil Temperature Life Expectancy

175[degrees]F 100,000 miles
195[degrees]F 50,000 miles
212[degrees]F 25,000 miles
235[degrees]F 12,000 miles
255[degrees]F 6,250 miles
275[degrees]F 3,000 miles
295[degrees]F 1,500 miles
315[degrees]F 750 miles

 

Here's anpther. Same chart, but with a little explanation.

http://www.tciauto.com/tech_info/tra...expectancy.htm

 

I'm measuring at the pressure test port as well. On a hot day driving on the streets the temp stabilizes around 150-160. I haven't towed my trailer in the heat yet, but when I brought it home it hovered around 130f at the end of a 75 mile trip. Temps were in the 50's.

Anyone had the sender in the pressure port, then moved it into the cooler line out (hot side) of the tranny and compared the temp differece?

Eric

 

My F250 (01), with the V10 has the external cooler in front of the radiator. I pull occasionally. Do I need another cooler to keep my tranny cool? I am pulling light loads most of the time but occasionally pull heavy. Is that external cooler standard or part of the towing package?
Thanks
Kelly

 

i say just get a tranny cooler and you wont have to worry about it as much,they arent that expensive and its nt hard you can do it at home just follow the directions

 

My gut is that 80% of all the 4R100 transmission failures were due to excessive heat.

For most part-time travel trailer users, the act of backing a trailer into a difficult park position with a poor or untrained ground guide ends up in a disaster. Here is why:

The 4R100 reverse ratio is not very low, and the torque converter is slipping (generating great gobs of heat)! The vehicle is not moving forward and there is little or no air flow across the radiator(s). The rear differential is not optimized for reverse (this causes more torque load) and the poor ground guide requires 100% of the drivers attention. By the time the trailer is finally up the hill, leveled out, and straight in the parking spot, the trans temp has spiked well over 250F for several minutes.

I doubt very many savy drivers ever killed a 4R100 climbing a tall mountain IF they had a Gage.

With no Gage that same dynamic can happen. Very hight torque loads, reduced speed (little or no air to cool), engine at 5000RPM, and torque converter slipping generating LOTs of heat.

Fords factory trany oil cooler is just barely adequate in normal conditions. I assure all of you: On a 100F day with a heavy tow/haul load it is NOT enough to keep the temps below 180-200F at high speeds in modest hills.

For years I have been recommending the very inexpensive insurance of an additional aux trany cooler and install a temp Gage.

All gages, unless calibrated against a near perfect "standard" are a compromise and are BEST used for RELATIVE comparisons.

That is...... relative for us owners and users.... a different usage need than a mechanical troubleshooter who needs to know the exact min and max and compare the item to a standard to determine if there is a fault or if a repair worked. We just nned to know when it is too hot.

Back to use owner/users..... we need to know what is NORMAL and we need to know if the component (in this case a transmission) is getting dangerously close to failure so we can take steps to reduce the problem (like slow down or turn on a fan etc...)

That said, I think from a mechanical point of view that the temp probe/sensor as first item in the out-put stream heading to the factory cooler will give equally good indication of max temp. But it will be earlier than placing the probe in the factory provided body port.

In the Factory trans "body port", the max indication will not happen until the entire trans housing and fluid are up to full operating temp. But ultimately either location should indicate within a few degrees of max temp.

I have a half dozen posts all over this and the diesel stop web sites on how to install a aux cooler.

Bottom line is a $35-55 Gage and a $39-79 cooler plus one or two hours of your life can save $5000 and two weeks of grief.

 

yes, it's cheap, cheap, cheap. There are so many options now for coolers, some have built in fans if you have nowhere to mount them in the airflow. Some are 2" wide and up to 4 feet long so they can be tucked up inside a frame rail if need be. Some have transmission and oil cooling in the same unit. Adding a cooler helps in a few ways. It adds a quart or two of fluid. More fluid dilutes less fast so you keep more lubrication and additives longer. Fluid flowing into the hoses and through the cooler and back to the tranny gets cooled just from the trip.

And what Fred says about the gauges is important, they're not all accurate, so if in daily driving your's reads 120, and you know better because no tranny runs that cold, so when your gauge hits 180 you are hot and probably up around 250 really. So a little common sense can go a long way.

 

Installed a temp guage in the pan on my F53 chassis motorhome and it would not get above 145. Exchanged it and new one did the same. Went on trip pulling toad and still never got above 150. Just information for ya.

Roger

 

I tow quite frequently with my 01 F350 Triton V8 and I just recently installed a Tru-Cool HD Transmission Cooler with a 28,000 lbs GVWR capacity. As well as I just installed a Derale Deep Cooling Transmission Pan the other day, and poured fresh Mercon V fluid in as well as a new filter. While towing on a really hot day I've had my transmission temperature at around 200. I hauled my girlfriends parents holiday trailer home from a camping trip a few weeks back and it was a warm day that day, and there were several long, steep hills along the way home. The trailer weighed around 5000-5500 lbs roughly and pulled really nice, but I noticed my trans temp was reaching 200 and this was before I replaced my factory auxiliary transmission cooler with the more heavy duty Tru-Cool cooler and the Derale deep pan. But today I hauled a light load of scrap metal on my equipment trailer and today was an insanely hot day and I was driving a mixed drive of in town and on the highway and my transmission temp once again reached the 200 mark. I'm wondering if this is something to be alarmed about, or if this is within an acceptable range? I also have the 4R100 Transmission.

 

That's normal. The Ford spec is that you can run as high as 220°F all day long. The fluid isn't going to oxidize and be destroyed like they say in this thread. That used to happen in the 1960's, but fluids are a lot more heat resistant now. You can go as high as 250°F for no more than a half hour at a time without causing any problems.

If you want to lower the temps replace that aux cooler with one from a 6.0L truck. That will bring the temps down.

 

2001 F250 V-10. We tow a 5th wheel 5 ton gravel travel ocassionaly. Had the gvwr as high as 28k a couple of times. 25 minute trip back from the quarry with a couple of hills. Have a gauge with the pickup in the pressure port. Highest temp I've seen was 196 degrees. Thinking about the 7.3 or 6.0 cooler mod. Or 4.3 axel ratios. And headers. Darn thing is the truck runs fine and with 220k I'm not going to drop more money into fixing something that's working great.

I will attest to the backup issue...we blew the rear main backing up the trailer. Small truck fire. You do have an extinguisher in your truck, right?

If you back up with the 4R100 I was told go 4 low with a load.

-Mac