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! :)

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.

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.

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

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.

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.

Well, you CAN have both on the chip. It's not good practice though because if you accidentally hit an up or down button too many times and switch the hex code when the engine is running and while everything's powered-up, the engine can die or keep running with messed-up parameters for that key cycle which is not good.

For instance, if you want both calibration families on the chip, put one set (say VRAA7S6) on positions 1-4 and do not go past that with the engine running. Then put 5-8 (or whatever) as the VRAA6S3.

To change between the two, the engine has to be off but the key in the run ("on" position). To switch from the 1-4 set to the 5-8 set:

1. Stop the engine
2. Turn the key to "run"
3. Change switch position to "05" (or whatever position starts the other set) and wait for the confirmation blink. Your wait to start light may flash and you might hear a click. Normal.
4. Turn the ignition back "off".
5. Restart the engine normally.

Use the second set of calibrations as you normally would. Switching on the fly is fine. Just don't go to the other set (1-4 in this case) while the engine is running and especially while driving. To switch back to the other set of hex code calibrations, repeat the above steps.

Got it!I think for now I will only run one Code so I do not have any issues. Thank you again. It will be a week or more before I can give this a shot as we are leaving town for a week to visit my In-Laws.
Have a happy Easter everyone.

Kent

Could we get some feedback if this helped with shift problem’

I have same symptoms

Thanks

Ok well I reflashed to the VRAA7S6 and I can definitely agree the shift points are much better. No hard downshifting.

Thank you for suggestion. Will report back if any quirks arise.

Cheers all!