What kills the transmission?
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Ive been reading a lot of transmission failures affecting 7.3L and I was wondering whats causing them and how to prevent them
Im a newbie and currently shopping for an excursion. TIA
[/ QUOTE ]the guy that replaced mine said make sure fluid is full and changed every 50000 miles and not to let them get hot above 221*. he said if it stays cool and ur fluid is good it will last a long time. me i had low burnt fluid and i hauled a obs f250 and i burnt mine up pretty fast, got hot and kept on it.
Ive been reading a lot of transmission failures affecting 7.3L and I was wondering whats causing them and how to prevent them
Im a newbie and currently shopping for an excursion. TIA
[/ QUOTE ]the guy that replaced mine said make sure fluid is full and changed every 50000 miles and not to let them get hot above 221*. he said if it stays cool and ur fluid is good it will last a long time. me i had low burnt fluid and i hauled a obs f250 and i burnt mine up pretty fast, got hot and kept on it.
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909 Posts
#1 High heat. A larger cooler is a good idea.
#2 4r100's were designed to shift like a car. A valve body is a must... ~$225
#3 That right foot. (It wont hurt too much if you take care of #1 and #2)
/ubbthreads/images/graemlins/grin.gif
#2 4r100's were designed to shift like a car. A valve body is a must... ~$225
#3 That right foot. (It wont hurt too much if you take care of #1 and #2)
/ubbthreads/images/graemlins/grin.gif
What are these problems of which you speak?
(Just back from a high-temp, well, for Michigan it was high-temp, tow of about 9500 lbs and barn-like frontal area with my 207.5K truck on the original engine and 4R100, which have never been apart at all, nor have they any reason to be taken apart.)
Seriously, most of the "problems" people have with the trans, apart from the 2001 mechanical diode, are largely a result of overloading (exceeding GVWR/GCWR) or overpowering (chip, tuner, etc.)
But yeah, heat is the killer. Ford specs say 221F max steady-state (at the sump; the pressure port everyone uses for temp senders is a reasonable surrogate), with brief (30-45 minutes at a stretch) excursions to no more than 248F, such as towing heavy up a big grade. Keep it under that, maintain the fluid per the PM schedule, and you should get good service life out of your trans.
(Just back from a high-temp, well, for Michigan it was high-temp, tow of about 9500 lbs and barn-like frontal area with my 207.5K truck on the original engine and 4R100, which have never been apart at all, nor have they any reason to be taken apart.)
Seriously, most of the "problems" people have with the trans, apart from the 2001 mechanical diode, are largely a result of overloading (exceeding GVWR/GCWR) or overpowering (chip, tuner, etc.)
But yeah, heat is the killer. Ford specs say 221F max steady-state (at the sump; the pressure port everyone uses for temp senders is a reasonable surrogate), with brief (30-45 minutes at a stretch) excursions to no more than 248F, such as towing heavy up a big grade. Keep it under that, maintain the fluid per the PM schedule, and you should get good service life out of your trans.
[ QUOTE ]
What are these problems of which you speak?
(Just back from a high-temp, well, for Michigan it was high-temp, tow of about 9500 lbs and barn-like frontal area with my 207.5K truck on the original engine and 4R100, which have never been apart at all, nor have they any reason to be taken apart.)
Seriously, most of the "problems" people have with the trans, apart from the 2001 mechanical diode, are largely a result of overloading (exceeding GVWR/GCWR) or overpowering (chip, tuner, etc.)
[/ QUOTE ]the guy that built my tranny asked me if i had a tuner/chip, i said yes and i also told him how i drive and all that. he said it would not hurt the tranny at all unless i had the chip on max and was pulling a real heavy load.i said what do i do,his response was put the chip in tow mode(dps tow settings). i also noticed in his lot was 99% superdutys. he said the 4r100 was the weakest link to the truck.
What are these problems of which you speak?
(Just back from a high-temp, well, for Michigan it was high-temp, tow of about 9500 lbs and barn-like frontal area with my 207.5K truck on the original engine and 4R100, which have never been apart at all, nor have they any reason to be taken apart.)
Seriously, most of the "problems" people have with the trans, apart from the 2001 mechanical diode, are largely a result of overloading (exceeding GVWR/GCWR) or overpowering (chip, tuner, etc.)
[/ QUOTE ]the guy that built my tranny asked me if i had a tuner/chip, i said yes and i also told him how i drive and all that. he said it would not hurt the tranny at all unless i had the chip on max and was pulling a real heavy load.i said what do i do,his response was put the chip in tow mode(dps tow settings). i also noticed in his lot was 99% superdutys. he said the 4r100 was the weakest link to the truck.
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Also, backing a trailer up hill into a campsite gets it hot real quick, too. Bigger trans cooler helps. David
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Above is due to no fluid is going to cooler in reverse.
Bill
[/ QUOTE ]ud think ford would have thought of that.
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Also, backing a trailer up hill into a campsite gets it hot real quick, too. Bigger trans cooler helps. David
[/ QUOTE ]
Above is due to no fluid is going to cooler in reverse.
Bill
[/ QUOTE ]ud think ford would have thought of that.
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6,286 Posts
[ QUOTE ]
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Also, backing a trailer up hill into a campsite gets it hot real quick, too. Bigger trans cooler helps. David
[/ QUOTE ]
Above is due to no fluid is going to cooler in reverse.
Bill
[/ QUOTE ]Actually I think the fluid still goes to the cooler but there is no airflow through the cooler and hence the ATF cooks. I would be very surprised if there is no pump flow in any gear.
[ QUOTE ]
Also, backing a trailer up hill into a campsite gets it hot real quick, too. Bigger trans cooler helps. David
[/ QUOTE ]
Above is due to no fluid is going to cooler in reverse.
Bill
[/ QUOTE ]Actually I think the fluid still goes to the cooler but there is no airflow through the cooler and hence the ATF cooks. I would be very surprised if there is no pump flow in any gear.
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124 Posts
I have 140,000 on original tranny & TC. pulled 23000 lbs truck an trailer combined in missouri up an down hills. I usually pull with the overdrive on as long as it is not shifting in an out of overdrive. The tranny will run alot cooler in overdrive about 170-180 usually . with overdrive off it goes up to 210 pretty quick an stay there untill i put in overdrive again then it takes several miles to cool it back down.
My 20001 E350 w/60000 miles tranny bit the dust today. I had it serviced about 5000 miles ago. Over the life of the van I have towed nothing more than my 21' Seapro center console....on a 3100GVW trailer. All towing has been on Maryland's Eastern Shore back and forth from the Ocean(maybe 5000 towing). All flat towing. I was crusing through a shopping center parking lot...felt a CLUNK....and D was gone... I limped home in 2nd at 40mph...
Giz
Giz
I had two trannies completely puke their guts out in the 2000 I had. Both times excessive heat was the culprit. I installed a big cooler and fan, but that did not even help enough. Both times the truck was pulling a load slow with no air movement. The stock trannies are incredibly weak when you ask them to work on a farm.
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180 Posts
[ QUOTE ]
I had two trannies completely puke their guts out in the 2000 I had. Both times excessive heat was the culprit. I installed a big cooler and fan, but that did not even help enough. Both times the truck was pulling a load slow with no air movement. The stock trannies are incredibly weak when you ask them to work on a farm.
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I wonder what the actual temps were in the transmision and what the listed flash point/viscosity index ASTM-D2270 of the actual fluid used?
most likely the fluid overheating caused the failure, any type of discount ATF should not be considered for such a complex unit.
I had two trannies completely puke their guts out in the 2000 I had. Both times excessive heat was the culprit. I installed a big cooler and fan, but that did not even help enough. Both times the truck was pulling a load slow with no air movement. The stock trannies are incredibly weak when you ask them to work on a farm.
[/ QUOTE ]
I wonder what the actual temps were in the transmision and what the listed flash point/viscosity index ASTM-D2270 of the actual fluid used?
most likely the fluid overheating caused the failure, any type of discount ATF should not be considered for such a complex unit.
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427 Posts
My transmission went at 89,000 miles. I hate to admit it, particularly on this forum, but my failure was likely due to lack of service. I did not have the fluid changed until about 75k miles /ubbthreads/images/graemlins/blush.gif. I was always good about the engine oil and coolant but I let the transmission go and paid the price. Now, $4000 later, I am a compulsive fluid changer. Thanks to this forum I have the technical resources and therefore the confidence to do these things myself. Thanks TDS members!
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12 Posts
driving around town in OD will wear out trannys pretty quick. it sucks that all trucks automatically start with OD on.
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