2001 F350 4r100 with Hydra. Truck has a DieselSite Legendary transmission, billet triple disk, modified valve body, everything minus billet shafts. Having a harsh downshift from 4th to 3rd when towing. Have been dealing with this in some way or another since I installed the Hydra, custom tunes and canned. When I am towing and it drops to 3rd it will spill a cup of coffee. The wife spilled coffee on herself 3 times yesterday. Some tunes are worse than others, Hydra tow tunes are the absolute worst, cant use them at all. 1023 tuning had similar issues but it was the 3rd-4th upshift instead. On the 4th-3rd downshift it is a rock solid shift and will perform it in a split second. With the Hydra pulled off it is just fine. (Not turned to stock but totally removed) If I let out of the throttle and hit the od/off it is a smoother shift.

My question. Is my truck compatible with a different Hex code file that has nicer TC lockup characteristics? My truck has an NMC2. Everything else is good just the 3-4 4-3 shifts and lockup. 1023 tuning caused it to slam going 3-4 and canned hydra is the opposite. 1023 pulled all the line pressure plus some and it was still too harsh.

Also thought about a good set of traction to help it out. Would rather it just shift normal though. I understand it is built to shift fast and firm but is not desirable while towing when it is harsh.

Thanks

 

It's the problem with aftermarket calibration vendors using NMC1 (50-state variant of PMT1).

It is VERY crappy when towing for this very reason. Everything else is ok except this characteristic which is fixable in the current tuning but you may want to have your current vendor just write you a set of NMC2 tunes.

 

Thanks for the reply. Can it be solved by using a canned NMC2 tune or only with custom tuning?

 

The current calibration I am using is VRAA6N3.

 

Go to the Hydraflash server and just put in a few VRAA7N7 calibrations. There isn't the selection but you will know immediately if it's something you want to persue.

You won't be able to switch between the VRAA6N3 and VRAA7N7 calibrations while the engine is running....just keep that in mind.

 

Unable to locate an VRAA7N7 files on the Hydra.

 

I can't get there without a Hydra chip where I am but it would basically do what you are able to do by pulling the chip or going to bypass "00" if I assume that you have an NMC2 or NMC3 PCM stock.

I did not think it through though that be there NMC2 tunes on the Hydraflash server or not, none will be setup with a modified transmission or valve body option anyway and all of your shifts would be pretty harsh except the moment of 4-3 downshift.

I'll check tonight when I get home as to what's there.

 

Tried a VRAA6S3, shifting is spot on. Only thing is I dont think it will activate the GP module.

 

It won't but it should still have an aggressive 4-3 downshift (unlike the NMC/PMT2)

 

It was agreesive(ish) but much more tolerable than the other tunes. Figured it wouldnt heat the plugs and then threw a code so no bueno. Are the NMC hex codes the only ones that activate the GP modules? Pulled it completely, 4-3 downshift unlocks TC for a second or two and lockups in 3rd nice and smooth. Put an order in for a tune with Jelibuilt. Made mention of the harshness with the NMC1 hex I was using. Hope then can get it sorted out no problem, is an NMC2 tune particularly hard to write?

 

No, the Excursion ones will work too but they require PATS (Passive Anti-Theft System) module data to let the engine start.


Yep. That's the main difference (and the only one you'll feel). There are a couple more things going on in each but you'll never notice driving it. NMC1 releases and instantly reapplies the converter clutch on the 4-3 downshift. NMC2/3 do not. They delay the reapply of the torque converter clutch for 2-5 seconds depending on load. It's a hindrance when driving aggressively as there isn't much power to the wheels at 3000+RPM with a sloppy converter for those few seconds but it really sucks to have that huge jerk with the earlier calibration.


No. It's no different to tune than any other calibration. There are a couple reasons that NMC1 is used over NMC2 and they're the same reasons nobody really offers PMT2 tuning either. However, it's entirely possible to get rid of the instant reapply with NMC1....just gotta know what to change.
1. More people than not just daily drive or drive spiritedly with their trucks. The issues you have are the same as everyone else that uses aftermarket tuning from the "custom" tuning crowd but you drive in a way where it is unacceptable; most don't notice. Also , some hate the "lag" on the 4-3 downshift and want it gone from their PMT2/3 and NMC2/3 (it exists on the 02-03 trucks stock too).
2. It's way easier and time-conscious to write one set of tuning that works for most everyone and not duplicate the tuning to other strategies. Why write 45 sets of tunes when you can get away with 10-12?
3. "Tuners" are cheap. Why buy all of the definition files (VRAA6 and VRAA7 in this case which are different enough that MOST of the commonly-changed stuff matches up) when you can just buy 9 and tune all of the major PCM families? I think Bill (Power Hungry Performance who sells the software to nearly everyone "tuning") has around 20 available but they cost a lot per file so just getting the minimum to start selling tuning the most popular strategies makes sense.

 

Well shoot, see how a tune from Jelibuilt works. Everything you said makes perfect sense and thank you for your time. Just trying to get something I can tow heavy with.

Next question...I also have a 2000 Excursion (dont have the hex code yet) Can I swap the PCM with my truck by chance and get softer tunes? Go back to an SCT flash tuner that leaves the transmission shifts alone?

 

You can install the Excursion PCM but it won't start. It needs to see an input from the PATS module ( verifies the correct key is used in the ignition) or it will disable the fuel.

Unless you get tuning to disable the PATS in the Excursion PCM, it will do you no good to swap it.

 

Got home about 15 minutes ago, grabbed a Hydra chip, hooked it to the computer ..... The new computer.....

It's amazing how much stuff you take for granted when you replace a computer. I'm sitting here waiting for. NET Framework 3.5 to download.

 

You're right. That library has been pared down a bit since the last time I looked at it. However, there are a lot more "complete sets" for some of the more obscure ones and vans.

There is also PMT3. Hmmmm. Nice!