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| 1999 to 2003 7.3L Power Stroke Diesel 7.3L Power Stroke Diesel equipped Super Duty and Excursion. |
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#1
Wed, March 15th, 2023, 05:11 PM
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Hard Transmission Down Shift
I have a 2001 Ford F-350 CC Dually with ~190,000 miles on her. She has a John Wood TowMaster with about 50,000 miles on it. I have a Wicked Wheel II and a Riff Raff open Air Cleaner, man can she sing! I have downloaded multiple towing tunes, both with modified valve body and without a modified valve body.
My problem is when the truck downshift while pulling a load, a 24' enclosed car hauler with 2 Can-Am Spyders each approx. 1000 lbs. so guessing 5000 lbs., it slams the transmission hard enough to shake the truck going down the road. I have selected both the non modified as well as the modified valve body tunes and both have the same results. In Stock setting transmission downshift just fine, nice and smooth. Can anyone give me an idea of what tune to try next time I tow other than Stock? Thank you in advance, Remark2013! 
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#2
Tue, March 28th, 2023, 08:55 AM
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Is this on the 4-3 downshift or the 3-2 downshift? What speed are we at?
I'd be happy to take a look at the issue and see what we can do to soften things up.
__________________
Bill Cohron - The Mad Doctor   Power Hungry Performance - The ORIGINAL in Ford performance tuning... Since 1997! (678) 890-1110 www.gopowerhungry.com - Home of the Hydra Chip, Minotaur Tuning Software, and the new Orion Reflash System for Navistar! Bring back  Windows™ XP and 7.  Windows™ Vista and Windows™ 8 is a pain in my a$$!  Windows™ 10 is only slightly less annoying!  Windows™ 11 is garbage!  Much to my surprise, I'm actually quite enjoying Linux! 
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#3
Tue, March 28th, 2023, 09:07 PM
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I'm going to guess that he had a VRAA7S6/8 calibration stock and now is using the VRAA6S3 and the issue is on the 4-3 since there are lots of folks out there who complain about it (not just from PHP customers either). It's kind of the nature of the beast.
I used to love the instant reapplication of the torque converter clutch to get the power to the ground and it was fine when not towing because the truck never really had to do a forced downshift. After towing a bit with it I learned to hate it and quit tuning with VRAA6S3 in its native state; ultimately modifying all the towing tunes with the delay that the VRAA7Sx calibrations have. It's annoying for sure but not as brutal as the instant reapply.
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Tuning, PCM flashing, and burning chips for 7.3s since 2008. Repairing all aspects of 7.3L Powerstrokes for 25 years. Eight 7.3L PSDs in the driveway including a 1994 Crown Vic and 1973 F100/2002 F350. Looking for the next victim. Last edited by cleatus12r; Wed, April 5th, 2023 at 05:05 PM.
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#4
Wed, April 5th, 2023, 09:17 AM
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It's the 4-3 downshift that it happens, I don't feel it when running unloaded but put a loaded trailer behind me and the transmission will downshift hard into 3rd hard. I am currently running the "VRAA63S" programing. If there is another compatible program, I am open to try it.
Kent
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#5
Wed, April 5th, 2023, 04:53 PM
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Quote:
Download a set of VRAA7S6 calibrations and give it a run. Just DO NOT mix the VRAA6S3 and VRAA7S6 calibrations on the chip as the engine will likely stall or cause a severe stutter when going from one hex code to another.
__________________
Tuning, PCM flashing, and burning chips for 7.3s since 2008. Repairing all aspects of 7.3L Powerstrokes for 25 years. Eight 7.3L PSDs in the driveway including a 1994 Crown Vic and 1973 F100/2002 F350. Looking for the next victim. Last edited by cleatus12r; Wed, April 5th, 2023 at 05:04 PM.
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#6
Wed, April 5th, 2023, 06:23 PM
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Just so that I am clear on this, you are saying to change all the programs over to the VRAA7S6 code and to not have any of the VRAA6S3 codes on the chip?
Kent Oh, and by the way, thank you very much for helping me out on this.
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Hybrid Mode
