Diablosport Forums

Well, I updated to 9r04 finally and the firm shifts are back. I started a new thread (here's the link http://www.diablosport.com/index.php?na ... pic&t=7106) with more info for all that have had this issue. It's just my opinion and experience, but I'm happy with 9r04 for the most part. Thanks.

COLD_ZERO wrote:Hi Johan-

Actually, you should scan forums from about 4 months ago on. We have been promised resolution many times. There are 14 guys in my group all with the same '07 ChSRT8s. We posted on here a bunch, too. It's every rev. Just do a search on my name on even this forum. Most of my posts have been about this issue.

There are a whole bunch of people with that downshift issue. In automatic ("D") it will not drop down like it did before the tunes. We've pulled fuses, reset modules, everything.

Thanks for your quick response on that post, by the way. Just please take a moment and search my user name- should be the last 15 posts or so.

Thanks.

Seriously, DS Team, are we just going to sweep the crappy auto downshift issue under the carpet at this point? We've been told for 6 months that it's being worked on, and now you guys post that "seriously, we scan the foums and not many people have this issue"???? It's on your own forums, too! Again, scan my posts and see.
Finally, if you don't plan on addressing the issue, as you've stated you would in your very own forum, just freaking let me know already. JUST SAY IT. Because I can then proceed to find another option instead of trusting you and believing you that you're working on it.

I guess I'm an idiot for believing you for so long, but I don't feel badly because you had a good reputation for addressing issues.

But, come on, "Not many people have this issue in 07 Ch SRT8s"????????? Just look in yor forum, srt8oc, lxforums, etc., etc., etc. Search for my name. I'm usually in the threads.

He he, i am going to leave my personal comment out of this.
I am on the LX forum everyday and have yet to see complaints about poor downshifting for 07 srt8's, so please enlighten me.
In your case what revision of the predator are you referring to? And what parameters have you adjusted.

I had downshifting problems with 8r20 on my 08 but 9r04 has cured that very well.

I hope this doesn't cause a diversion from anyone else's concerns but these are my observations.
First, everyone should make a clear distinction between the 5.7L and 6.1L. The firmer shift option for the 5.7L puts the transmission parameters to the equivalent of the 6.1L parameters (same transmission). The 5.7s also have MDS as another factor. Shift "feel" is subjective so discriptions of the same thing can vary. To add to the confusion some people are comparing and talking about different things when they think they are talking about the same things. Keeping all that in mind. I have a 6.1L, I have only used 8r20 with raised shift points.

When I first loaded the CAI91oct tune I selected raised shift points and reset TCM.
The 1-2 shift was ok but didn't feel much, if any, firmer than stock. The 2-3 shift was positively spongy, very different from stock. It sort of felt like a rubber band. I was worrying about my clutches. Unfounded. It seems the NAG1 is damned near bullet proof so you probably don't need to worry about the clutches with less than maybe 600 hp at the wheels. I figured it would get better but it didn't -- at least not then. I've been tweaking my tune for weeks. Somewhere along the line the 2-3 shift must have firmed up because it's not spongy any more. You don't need a kidney belt, but it seems to be how I remember it from stock. Keep in mind that I'm using raised shift points so I'm shifting further up in the power curve. That's got to effect the feel somewhat. Even back when it was spongy I was getting a significant improvement in times so I don't know if that helped or hurt. As far as "feel" goes, I think I would prefer to feel like I got kicked in the butt on shifts. I'd even sacrifice some time for that, just me. In any event, there has been a significant change in the upshifting over time. I can't imagine that the TCM adaptives, if there are any, and if they would effect this, would take that long to adjust. Apparently they did? The shifting did change and over a long enough time that I didn't notice when.

Down shifting has been fine. I haven't noticed any difference in down shifting from the stock behavior, except for this: When in autostick (doesn't do it in automatic), and coming to a stop without manually downshifting the 3-2 shift is like a clunk. It sounds/feels as if I have a worn U-joint. It's not really bad but it's very noticeable. This is like when you're coming to a stop at a red light and as you get down to about 5 or 7 mph the car will downshift to 2nd (once you actually come to a stop it downshifts to 1st). It doesn't do this in automatic.

my 5.7 does the same thing since 9r04, when its coming to a stop in autostick mode it clunks going to 1st

Yup... my 5.7 does it too... not in "D" just in Autostick from 3-2 but only when my firmness and shift points are raised, regardless of tune or stock... since the 5.7 shift firmness and shift points are set to 6.1L settings, must be a 6.1 flaw... j/k

I notice a firm and abrupt down shift in stick mode with the tune in
It is a hard downshift that goes away with the return of the stock tune.
I am not saying it is a bad thing, just that it is there.

I have a feeling that clunk could be due to the reduction in tm.

Yeah, I thought that might be the issue, I should have stated that it was not a concern for me... just an observation.

johan wrote:I have a feeling that clunk could be due to the reduction in tm.

So the implication is that, with a SRT8, with the tune, shifting in autostick is different than shifting in automatic?

Could you tell us what's different (sounds like TM)?
And if you think the performance difference is significant could you quantify it?

I can take a stab at this.... with the car in "D" the downshifts happen at a nominal time in the speed calculation. I believe that in Autostick mode, the Torque Management and TCM downshifts at the lowest possible speed programmed in the PCM. In "D" my car shifts to 2 from 3 at a quicker speed than in autostick. It's like the TM is telling the transmission to:

"HOLD THAT GEAR as long as you can, the driver is in Autostick mode, he must know what he wants, no?"

How'd I do?

fordomatic69 wrote:How'd I do?

ummm, I'm guessing "close, but no cigar". LOL

Yes, I would expect a different downshift shift point. But, that is initiating the shift and not the actual shift itself. I believe shift initiation is handled in the PCM. Also some TM parameters are set by the PCM. The actual shift (up or down) is primarily handled by the TCM.

I'm curious if these parameters (the TM ones) are set on a per shift basis?
Does/can the Predator set different TM parameters for autostick than automatic?
Does/can it set TM parameters differently for upshift than downshift?
If so, any quantification on performance gains?

johan wrote:He he, i am going to leave my personal comment out of this.
I am on the LX forum everyday and have yet to see complaints about poor downshifting for 07 srt8's, so please enlighten me.
In your case what revision of the predator are you referring to? And what parameters have you adjusted.

He he, I am going to leave my personal comment out of this.
Here are some examples that you, in your "everyday" visits to LX forum, as just one example, to "enlighten" you.
Read through them in full. It will tell you that even your canned 93CAI unmodified has been causing problems for a long time.

http://www.lxforums.com/board/showthread.php?t=88345

Here's some from your own forum
http://www.diablosport.com/index.php?na ... highlight=

http://www.diablosport.com/index.php?na ... c&start=15 (See Jected's comments, Mike Levy's, etc.)

And, for the 4th or 5th time I'll say you should run a search on some forums, so your customers don't have to, on things like "predator""downshift""automatic", etc.

So, now we can finally get by DS's defensive answers that this has never come up before, right?

Yep, I'm still having the issue. It went away for a while, but at this point it again doesn't want to give up the higher gear. I also don't have 5th available when using the stick.

07 SRT8, 93 CAI tune, 9r04.