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AllYourBaseAreBelongToUs
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What is the max temp you should allow your transmission toget too for an extended period? Seems like it was 220deg. but I'm not really sure.

My trans temp is about 185 around town and I'm about to make a road trip to Panama City. Just wanna make sure I don't overheat it since this is the first "long distance" trip I'll have made since putting the trans back in.
 

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I think ford's spec on the high end is 248º, but this is for 5 minutes or less to be safe.

I have seen 220 but I had good reason. Very steep, slow, off road driving with my truck full and pulling a trailer with 6 horses going elk hunting.

The situation really dictates what's acceptable, in my case I felt 220º was perfectly acceptable because of the load I was putting on the trans.
BTW, I went to low range the next couple days and it stayed much cooler, less stress.

220 just running down the freeway empty is certainly a little high.
 

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I also agree with kanman on the fluid, if it ever does get that hot for just a short time, may not kill the trans but definitely does a number on the fluid.

I would replace fluid if I had it in the 240-250 range for very long at all.
 

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Laces Out
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at 240 you begin to lose trans fluid out the breather i believe..and i know for a fact the od on/off light flashes..thats way hot and bad for the fluid and the seals.
 

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Local Machine Gun Builder
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Lost the Ford Reman in my '97 about 2 months ago. HAd to climb a STEEP grade 1st gear, 4 lo, fluid coupling the whole way up for 6 miles towing 8,500, road too narrow and no pulloffs. Kept watching the temp gage which got up to about 220 on the way up. Top of the mountain levels out flat, was able to get some speed and watched the gauge go down but puked enough out the front seal and the truck stopped moving forward. Filled it up with some fresh ATF and drove it home 200 miles to the tranny shop.
Tranny shop said it was definitely in bad shape. New tranny, new coolers, and now can't get it over 180 even in this heat.
 

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Really it you want any kind of life out of an automatic you should keep the fluid temp under 200*F sump temp. There are a few exceptions but they don't apply to 4R100's. You can run a lot of temp, but the oil and particularly seals and square rings can take it for only so long.

The hotter the oil gets the more it bakes the seals and they get harder. The harder the seals get the more oil they will bypass, which is particularly bad on items like apply clutch seal rings.

I don't like to see more than 185*F sump temp for any length of time on my personal stuff. I also change the fluid quite often, around 10K miles. The color of the ATF is a poor indicator of it's state of life. When the ATF changes color it is getting really close to too late. The friction modifiers are particularly important and you can't see that in the color of the oil, but they do get "used" up.
 

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Grumpy Old Bitter Bastard
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What is the max temp you should allow your transmission toget too for an extended period? Seems like it was 220deg. but I'm not really sure.

My trans temp is about 185 around town and I'm about to make a road trip to Panama City. Just wanna make sure I don't overheat it since this is the first "long distance" trip I'll have made since putting the trans back in.
Danny, what is your definition of extended periods. 220 for 15 minute hill climb, that's not too bad, but 220 for a hour, I'd be worried. I run 150 empty, 180 moderately loaded. I have yet to see over 200. While 185 around town is OK, it does seem a bit high for an unloaded truck. I'm guessing with your higher trans pressures and all, it will probably run hotter, but not 220 continuously.
 

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Last month I pulled my fiver up a steep hill with many switchbacks, and I got it up to almost 260 for maybe 5 minutes. The ATF looked fine, but didn't smell right. It wasn't burnt (& I didn't lose any going up the hill), maybe call it lightly toasted :shrug:. I dained the pan & replaced the filter in the pan. It's not had any problems, so I think I'm okay.
With a stock tranny, I would have stopped a few times going up that hill.
 

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USN-Retired
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Danny, what is your definition of extended periods. 220 for 15 minute hill climb, that's not too bad, but 220 for a hour, I'd be worried. I run 150 empty, 180 moderately loaded. I have yet to see over 200. While 185 around town is OK, it does seem a bit high for an unloaded truck. I'm guessing with your higher trans pressures and all, it will probably run hotter, but not 220 continuously.
I agree and I run just about 70 deg above ambient unloaded and even towing at 16K GCW running out of OD on 7% grades beating the snot out of my tranny in 90deg weather for 5 to 10 min. I have never seen over 190 to 195. While temps higher than 200 are not a real cause for drastic action, these trannies IIRC are designed to run most efficently at around 165 to 185 so anything warmer is not helping tranny life down the road. Also, two other things over the years I have noticed at least with my Van when towing is that even after an hour or two on fairly flat or Interstate type hills whatever my base temp is e.g. 150 to 160, if I get into the mountains and it gets up to say the 190 range it takes a looooooong time to come back down (like 20 to 30 min out of the mountains) and then it seems to like a base temp of anywhere from 10 to 15 degrees more until I stop and get it back down at least the the initial base temp.

LarryM
 

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Bleau May
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With the Ex having a BTS trans and a 6.0 trans cooler I don't recall if I have seen it hit 150*.
 
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