2000 F-350 dually, 7.3L diesel of course and i pull a 25' tandem gooseneck. I think the trailer weighs about 6000 pounds, and today with a load of about 13, 500 pounds on that trailer, and the other day with about 11, 000 pounds on, i have had my tranny up to about 210 degrees pulling some hills. I dont have it matted, im just doin a steady pull up a long hill. Whats the max temp i can run to? I usually stop at around 200, but it dont take much to get it there pullin hills. I am gonna do a tranny service and see if that makes a difference. Otherwise i guess its going to be some sort of tranny cooler or a new truck with a 6 speed. Thanks.

 

That's gettin on the verge of too hot. I wouldn't take it any hotter than that. What you need is a transmission cooler from a 5r110 transmission, behind the 6.0 and 6.4 trucks. Get one from a 05-07 6.0 and it bolts right in, all you need is two elbow fittings, and two short pieces of hose, and connect them right onto the factory steel lines. My tranny temp hasn't been over 160 since i've installed it. Basically if you have one of these, you will probably never ever have to worry about overheating the tranny again. It's about 3x the surface area of a stock one!

 

Your fine at 200-220. Red line for the 4R100 or any auto tranny for that is about 225-230. Syn fliud can take the higher heat better then dyno. Get youself a 6.0 cooler or a V-10 cooler and you should be fine. A TC lock up switch will help as well, keeping the TC locked at all times will keep the heat down alot!

210 is fine... I would not even get excited about that.

Also DO NOT turn the truck off when the tranny temps get to hot. Pull over, put the truck in N and high idle and it will still move the fluid and help to cool it.

 

[QUOTE=CSIPSD;6090663]Your fine at 200-220. Red line for the 4R100 or any auto tranny for that is about 225-230. Syn fliud can take the higher heat better then dyno. Get youself a 6.0 cooler or a V-10 cooler and you should be fine. A TC lock up switch will help as well, keeping the TC locked at all times will keep the heat down alot!



210 is fine... I would not even get excited about that.

Also DO NOT turn the truck off when the tranny temps get to hot. Pull over, put the truck in N and high idle and it will still move the fluid and help to cool it.[/QUOTE
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I think 220 is about the liimit and I wouldn't run it for an extended period.

I have the infamous early 99 and it has an even smaller trans cooler, I added the true cool in line with the stock cooler and while plowing this winter I went from hitting 220 to never over 140. When you are plowing there is no tc lock, so there is always some slip, to help I plow in 1st then there is no shift to cause more heat.

The 6.0 or V10 in line with the true cool is supposed to be the cats meow.

Now I have a question.

I have a tc lock up led indicator along with a switch to lock. My tc locks at 35 mph with the switch off and the LED never shuts off past 35 mph.

My question is I don't see the tc unlock, so what is the benefit of manually locking my tc if it appears to never unlock?

 

You can lock the TC at ANY time you want to.

 

Kirs, maybe I didn't explain my question well. I know I can lock my converter at any time.

My question was what is the benifit of manually locking th tc when it is are ready locked?

Like I said I have a LED that indicates when the tc is locked and it is locked from 35 mph too 80+ with out the switch on.

 

One of the guys posted a link to a question answer site and I can't find it now but the part that I saved was this:

"At 195 degrees F., for instance, fluid life is reduced to 50,000 miles. At 220 degrees, which is commonly encountered in many transmissions, the fluid is only good for about 25,000 miles. At 240 degrees F., the fluid won't go much over 10,000 miles. Add another 20 degrees, and life expectancy drops to 5,000 miles. Go to 295 or 300 degrees F., and 1,000 to 1,500 miles is about all you'll get before the transmission burns up."

Seemed logical at the time.

 

How about the bypass cooler line? I have seen them stick and overheat the trany with or with out the air to air coolers

 

im about to order up a tru cool off dieselsite hope to get that and some guages installed for this summer so i can tow with ease

 

Seems logical, but it isn't right. It may have been true for 1960's automatics, but modern automatics can run much hotter than that for longer times with no damage.

The continuous maximum temperature is 221F, and the maximum for no more than 1/2 hour at a time is 252F.

 

Yes, they can stick, but if they do the trans gets HOT. 210F towing 20k pounds is normal. If the bypass were not working right that trans would be really hot.

 

There is no benifit to manually locking when it's already locked. The solenoid will already be on, adding the switch to it won't do anything different.

 

Thanks Mark

 

Did a tranny service today and the oil and filter was a little dirty but not bad. No filing or anything, so thats good! Seems a little cooler, but im gonna hook onto a load of steel on my gooseneck tomorrow and try it.

I checked the auto wreckers and Ford for a 6.0L trans cooler, but ford wants $600( plus i refuse to deal with then unless i HAVE to) and the wreckers dont have one, so i guess im gonna have to Ebay it.

Kris, where exactly do you mount that secondary cooler? Thanks!

 

If you are purchasing the 6.0 cooler, remove the old 7.3 cooler and reinstall the new in the same place. Keep this in mind, the lines on the 6.0 are larger than the 7.3. A larger hose will be needed.