4r100 overheating
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4r100 overheating
I have a 2002 7.3 4x4 cc and the trans gets hot just driving around town not towing. I put a second cooler on it, I took the in line from the back of the trans of the passenger side and put it one side of the cooler let it run through the cooler and connected the underside of the cooler back up to the line. I changed the fluid about two weeks ago. Last night I was driving it for about a half hour and it wasn't overheating but as soon as I got into my neighborhood I turned the ac on full blast and before I got to my house the trans started to get hot. I'm not sure if that's related or not.And when I say hot I mean almost to the yellow and if I keep driving it, it will get up to the yellow. I'm stumped. I was reading about the bypass valve, but mark said in another post that's very unlikely. So if you guys have any ideas on what I should do, shoot.
Laughing Gas
Joined: Jan 2007
Posts: 870
Likes: 9
From: Carbondale, CO
I would start with checking flow rates per the attached link below.
https://www.ford-trucks.com/forums/1...l#post12797931
Not sure if this is how you changed your fluid, but attached is a thread using Mark's (transmission engineer) procedure. Good luck.
https://www.ford-trucks.com/forums/1...and-video.html
https://www.ford-trucks.com/forums/1...l#post12797931
Not sure if this is how you changed your fluid, but attached is a thread using Mark's (transmission engineer) procedure. Good luck.
https://www.ford-trucks.com/forums/1...and-video.html
Lead Driver
Joined: Jun 2007
Posts: 7,760
Likes: 27
From: Hampton, Maryland.
John Woods is a big believer in removing the bypass. I know he has a specially machined piece to replace it with. I believe you can pull the bypass and test it with compressed air to see if it is actuating too early. If I recall correctly it should take between 55 and 60 PSI before it bypasses. If it is much lower than that, you have found your problem. At that point you can choose to either replace it with a new one or go with the delete kit that john woods sells.
Trying to Gain Knowledge
Joined: Jun 2003
Posts: 1,571
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From: Ezzell, TX
I was having similar issues. I removed all coolers from the system, then installed a 6.0 cooler as my only transmission cooler and it has knocked my temps from an average of 210 down to around 160-170 depending upon ambient temperature. Not saying that is your case, but it is what I had to do to mine to get temps back down.
Ted
Ted
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I'm almost positive my truck already has the 6.0 cooler, I talked to a transmission mechanic in my town, the one who gave me the other cooler to install and he told me to bypass the radiatior and just run that and the other cooler. I wasn't sure how to do that so I just ran the other cooler in series with the cooler that was on the truck
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It's a Van Gogh
Joined: Feb 2010
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From: Elk Grove, CA
2nd trans coolers are generally bad. They allow pressure drop and if an old school tube and fin variety, are not that effective.
Best set up is to delete the stock 7.3 cooler, replace with a 6.0 cooler (26 row or 31 row basically equal), plus the trans cooler line in the radiator. The radiator cooling is substantial, get that hooked up again. This configuration will take anything you can throw at it.
Then do a flow test as mentioned above and go from there.
If you are going by the trans dash gauge, it is slow to react and basically designed to keep the driver calm. If it shows hot then it got seriously hot my friend. How's the fluid look and smell?
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Laughing Gas
Joined: Jan 2007
Posts: 870
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From: Carbondale, CO
I'm almost positive my truck already has the 6.0 cooler, I talked to a transmission mechanic in my town, the one who gave me the other cooler to install and he told me to bypass the radiatior and just run that and the other cooler. I wasn't sure how to do that so I just ran the other cooler in series with the cooler that was on the truck
Are you saying the small oil to air was replaced by 6.0 cooler, and you have now added another? 2 additional coolers and the trans cooling?
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The stock was replaced with 6.0, and I added one cooler in line with that
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Maybe if the new trans cooler is mounted directly on the surface of the AC condenser it would absorb heat from it. Otherwise I doubt it.
2nd trans coolers are generally bad. They allow pressure drop and if an old school tube and fin variety, are not that effective.
Best set up is to delete the stock 7.3 cooler, replace with a 6.0 cooler (26 row or 31 row basically equal), plus the trans cooler line in the radiator. The radiator cooling is substantial, get that hooked up again. This configuration will take anything you can throw at it.
Then do a flow test as mentioned above and go from there.
If you are going by the trans dash gauge, it is slow to react and basically designed to keep the driver calm. If it shows hot then it got seriously hot my friend. How's the fluid look and smell?
2nd trans coolers are generally bad. They allow pressure drop and if an old school tube and fin variety, are not that effective.
Best set up is to delete the stock 7.3 cooler, replace with a 6.0 cooler (26 row or 31 row basically equal), plus the trans cooler line in the radiator. The radiator cooling is substantial, get that hooked up again. This configuration will take anything you can throw at it.
Then do a flow test as mentioned above and go from there.
If you are going by the trans dash gauge, it is slow to react and basically designed to keep the driver calm. If it shows hot then it got seriously hot my friend. How's the fluid look and smell?
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,707
Likes: 2,628
From: SE Florida
It means either that there is a restriction in the cooler circuit, or that the cooler bypass on the side of the trans has failed. A rebuild for the bypass is very inexpensive and easy to install.
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Mark you're just the guy I was waiting to post, so I should rebuild the bypass valve and I should flush the lines too because there is most likely a blockage right?
Cargo Master
Joined: Mar 2008
Posts: 2,975
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From: Archdale,N.C.
Based on "my" transmission experience if you have a 6.0 cooler you shouldn't need an additional cooler. I tow a 38' 11,000lb TT and with ambient temps in the 90s my trans temp stays at 160 to 165 with a 6.0 cooler.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,707
Likes: 2,628
From: SE Florida
If you get stuck in stop and go traffic, or climb a steep grade at a low speed, or have to back your trailer uphill the air to oil cooler isn't going to do much for you. Going down the road it will be fine by itself. Get into one of the situations I just named and you'll wish you had a radiator cooler.