James - Sorry man, I didn't mean it the way it sounded. I did re-read what I typed and can see how it sounds like I'm saying your tune is the problem. "Typical Henson tune"
I never thought your tune was the problem but feel there are things that can help the problem. The tranny is one big mechanical pc that if everything is not working in sync you get these types of issues that can be called "small, noticeable something is not right, frustrating quirks". I don't feel this is a huge problem that if not address the tranny will blow up. With that said, I feel there can be an adjustment to the tune to help this. The other option is to tear down the tranny. This is something we’re trying to prevent. I fully agree with, you shouldn’t band-aid a problem by tuning, but I feel the tune can do the same exact thing that adding mystery oil can. In other words, this case is an exception to the standard rule. One thing to note is he says when upping the pressure the problem goes away.
By reviewing the vid posted, I noticed the “stagnant” spot in the rpm’s and quickly related to this from when I was tuning. I fixed this by locking the convertor at the right spots. It’s trial and error and is next to impossible to send out a “canned tune” and have it perfect because of every vehicle being a little different. One canned tune will work perfect for my vehicle, and not so perfect on the next. Keep in mind this “stagnant” RPM problem is not the shudder problem being described, which we didn’t see on the vid.
What I meant by the low shift from 1st to 2nd is I had your tranny tunes and I remember them shifting real early out from first to second. At first, it made the vehicle seem faster just because the owner will not be used to their truck shifting this fast. But like you, I started timing things and found improvements. The reason I feel holding the RPM’s longer in first helps, is not where it shifts from doing this, but where the RPM’s land after the shift. You may have it right with the canned tune where the vehicle will be in the best optimal power range thru the gear, but I did find improvement here.
As far as the locking and unlocking the torque convertor goes, my view may be different. I’ve found that, keeping the torque convertor locked as much as possible, helps reduce times. Really, I shouldn’t have to prove this one bit. When a torque convertor is not locked, it’s slipping. When it’s locked, it’s not slipping. Further more, slipping causes friction and friction causes heat. Heat is the number one reason for transmission failure, so for me it’s very easy. We’re working with 5 speed trannies here so we don’t have the problem of “bog” from locking the convertor too fast. On other transmissions, locking the convertor too fast may result in a “bog”. Then, and only then is where I would keep the convertor open a bit longer. If you’re concerned about the tranny breaking then I would experiment with the torque reduction tables and not the convertor tables.
These are my experiences only, and the bottom line is trail and error with the particular transmission being tuned. James probably has three times more experience than I do so his views shouldn't be taken lightly. I would like to see more information in this thread.