4r100 overheating when towing
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4r100 overheating when towing
I have a 2003 F250 4x4 crew cab FX4 with the 4r100 transmission. It stays cool when normal driving but I hooked a trailer to it the other day and it was an equipment hauler with nothing on it. The transmission was close to overheating so I pulled over and let it cool. It did blow some fluid out of it. The transmission seems to downshift and upshift constantly under the least bit of acceleration. The truck has around 207000 miles and Im unsure or when it was serviced. Fluid is a little dark. Transmission cooler and AC condenser are clean as can be. I have done a lot of reading on the forums but don't know where to start.
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I only have factory temp guage on the dash so I don't know the exact temp but it was touching the yellow on the guage. Fluid was not overfilled and I haven't taken it anywhere to get it scanned. Didn't know if there was something I could do myself to try or if it needed professional help. I had thought about adding an external cooler on the front of the AC condenser but didn't know if it would help.
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From: Isanti, MN
I'd first check for an obstructed cooler. You can pull the cooler return line from the transmission and direct it into a bucket. Have a helper start the truck and run it for 15 seconds and then shut it off. If you have less than a quart in the bucket your cooler is obstructed and the source of your problem.
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The one that connects to the transmission closer to the rear of the truck.
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I removed the rear line off the transmission first and checked it. It may have put out 1/2 quart and nothing came out of the transmission side so that tells me the bypass is working properly? I removed the line feeding the radiator cooler and it pumped out about 1 1/2 quarts in 15 seconds and the discharge side or the radiator cooler feeding the external put out right at 1 quart maybe a little more. All of these were done in the 15 second intervals. Does it sound like I need to replace the external cooler or bypass both and just add an external cooler? Would this also cause the issue with the transmission hunting when cold or is that another problem in itself? The fluid is pretty dark too probably from where I ran it warm a couple times hauling the other day.
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From: Isanti, MN
I removed the rear line off the transmission first and checked it. It may have put out 1/2 quart and nothing came out of the transmission side so that tells me the bypass is working properly? I removed the line feeding the radiator cooler and it pumped out about 1 1/2 quarts in 15 seconds and the discharge side or the radiator cooler feeding the external put out right at 1 quart maybe a little more. All of these were done in the 15 second intervals. Does it sound like I need to replace the external cooler or bypass both and just add an external cooler? Would this also cause the issue with the transmission hunting when cold or is that another problem in itself? The fluid is pretty dark too probably from where I ran it warm a couple times hauling the other day.
If I understand you correctly you've isolated the restriction to your external cooler. I'd start by replacing the cooler, flushing the system with THIS PROCEDURE, and testing again for flow. If still under one quart you'll need a new radiator. Sadly there's no good way to clean out an obstructed cooler.
And no, this wouldn't affect a shifting issue while cold.
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Ive seen a lot of people say that the one on the 7.3 is severely too small and to put a cooler from a 6.0 in but which year model 6.0? The 03 and 04 6.0 coolers are only 2" taller and is that enough difference or can I just put a good size on front of the condenser like a b&m or one from the parts store and just do away with the factory external? I looked is Summit and they had a pretty good size b&m for around $80 if I remember right.
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Ive seen a lot of people say that the one on the 7.3 is severely too small and to put a cooler from a 6.0 in but which year model 6.0? The 03 and 04 6.0 coolers are only 2" taller and is that enough difference or can I just put a good size on front of the condenser like a b&m or one from the parts store and just do away with the factory external? I looked is Summit and they had a pretty good size b&m for around $80 if I remember right.
I did the 6.0l conversion on my Excursion and was happy with the results. It requires splicing the lines to 1/2" to fit on the 6.0L cooler though, the 4R100 lines are 3/8ths if I remember right.
I wouldn't compromise and get a factory design cooler. They bolt in using the factory mounts and won't have you sticking things to your condenser. You can get an aftermarket cooler of the OEM design at RockAuto Parts Catalog. Pick a later 6.0L truck if you want to upgrade coolers, it will bolt right in.
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So the one on the left will bolt right in to where mine is now? I just need to know what year models will bolt in. I figure bigger is better. Which one did you put in your excursion? Is it the one in the picture on the left?
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Here is a size comparison shot I took, my stock cooler is bigger than the ones they put on the 7.3L trucks.
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Attached in post #4 is a link to Ken's (woodnthings) write up for the 6.0 cooler install. See if that helps clarify.
https://www.ford-trucks.com/forums/1...ns-cooler.html
https://www.ford-trucks.com/forums/1...ns-cooler.html