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I have a 2002 7.3 F350 XLT extended cab long bed single rear wheel that I bought new in 02- I maintain it immaculately and all maintenance is done by the book. It is all stock except for the Donaldson Blue 6637 air filter- the transmission started to flare and slip at 73,000 miles so it was replaced with a reman tranny by ford- while it was still under warranty it started to flare again so it was replaced with another reman tranny by ford at 98,000....it now has 112,500 miles(I don't drive it much)- it seems to run well and get between 14-15 miles per gallon, starts easily with no issues but noticed a few weeks ago when pulling my 5000 lb travel trailer in the mountains, when I would come up on a hill I would get to about 60 mph at 2200 rpm's and would find that my foot was on the floor....the tranny seemed to shift ok(up until that point)....the truck seemed to be running smoothly up until I got to a hill, then it seemed to not downshift into the lower gear- I could manipulate the gas pedal by punching it a little at the base of the incline to get it to drop into the lower gear but that is not how I drive, I drive with a soft smooth foot- I have never had to do that in the past, although I don't tow a whole lot I have used this truck in the past(5 years ago) to tow 10,000 lbs and it performed well shifting smoothly in very mountainous regions and can't understand what the problem is...(when I calculated my gas mileage at fill up it was crappy- 10.4...I usually get about 12)..I tow with overdrive OFF, there were no warning lights on the dash and the engine and tranny temp stayed normal....I am just sick about this hoping that the tranny is not failing AGAIN. I dropped the truck off with my Ford Mechanic on Tuesday and told him to keep it as long as he needs- it is now Saturday and haven't heard anything yet- I like to educate myself as much as possible with issues with my truck- did research all over the internet and YouTube and many people suggest dropping the fuel tank and cleaning the strainer cartridges and replacing the pickup screen/foot....I instructed my mechanic to do this(whether or not the current issue has anything to do with that) The fuel tank is a 38 gal plastic tank and I never use any fuel additives….does anyone have any thoughts or ever experienced anything like this....does it sound for sure like it could be the tranny or could it possibly be something else?? People rave about theses 7.3's and they can yank the side off a building but I am having this issue pulling this puny little travel trailer....and after being SO mindful about the care and maintenance of my truck I am feeling quit discouraged....I know I need to be patient and wait for the mechanic to call but was wondering in anyone had any input or ever experienced anything similar and what they did to fix it. Thanks!
 

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honestly the throttle style you mentioned is half the problem. Not trying to be rude but the 4r100 is not as advanced as newer units so you need to use your foot to force a downshift more often on these trucks. Not gonna hurt it or bad just a qwerk with 20yr old technology.

couple things to check: get a monitor to check boost, oil temp, trans temp, and icp/IPR reading to see if something is failing causing a reduction in power.

check the up pipes for cracks leads to reduced power/higher egts



Also I know how this sounds but I’d like you to try it. Look under the hood and find the red tube that goes from the intake plenum to the little metal looking cupcake on the turbo(wastegate).

unplug it from the metal cupcake and plug the end of the red tube back on the intake plenum.

these truck are programmed to let boost off way to early and you won’t hurt anything running stock injector/turbo even towing 12k.


5k weight is nothing at all for the 99-03 7.3l. You could tighten the little wastegate arm a turn or two too.A long long time ago a good friend told me to do it and I haven’t plugged it back in, in years. It just allows the truck to stay in the powerband longer to avoid up shifting.

I have an edge insight monitor to watch EGTs, oil temp, trans temp, boost etc. nothing even hotter at all I just gained a couple psi boost and made it altogether much better towing. I still regularly tow 5th wheels, skidsteer, side by sides, boats etc.
 

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honestly the throttle style you mentioned is half the problem. Not trying to be rude but the 4r100 is not as advanced as newer units so you need to use your foot to force a downshift more often on these trucks. Not gonna hurt it or bad just a qwerk with 20yr old technology.

couple things to check: get a monitor to check boost, oil temp, trans temp, and icp/IPR reading to see if something is failing causing a reduction in power.

check the up pipes for cracks leads to reduced power/higher egts



Also I know how this sounds but I’d like you to try it. Look under the hood and find the red tube that goes from the intake plenum to the little metal looking cupcake on the turbo(wastegate).

unplug it from the metal cupcake and plug the end of the red tube back on the intake plenum.

these truck are programmed to let boost off way to early and you won’t hurt anything running stock injector/turbo even towing 12k.


5k weight is nothing at all for the 99-03 7.3l. You could tighten the little wastegate arm a turn or two too.A long long time ago a good friend told me to do it and I haven’t plugged it back in, in years. It just allows the truck to stay in the powerband longer to avoid up shifting.

I have an edge insight monitor to watch EGTs, oil temp, trans temp, boost etc. nothing even hotter at all I just gained a couple psi boost and made it altogether much better towing. I still regularly tow 5th wheels, skidsteer, side by sides, boats etc.
Thanks for your input- as far as how I drive with a soft smooth foot I might say that you could have a point in that being at least part of the issue but I have been driving this truck since it had 3 miles on it with and without heavy loads on all kinds of terrain and I know that something is just not right- it has always towed like a beast....and now when I hook the TT up it DOGS on the hills with my foot on the floor.....my driving style has not changed....but I do appreciate the feedback an will try your suggestions!! Thank you!!
 
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