Auto Trans Tuning & Weather - Problem? Normal?

[jimlem]

I had a strange and un-nerving experience today. Every time my truck up-shifted from 2 to 3 and then 3 to D, it felt as if I was being rear-ended. Here are the particulars: 2002 1500 HD 6.0L 4L80E 4:10 E80 rear end & 32" BFG AT TAs. I run a Hypertech Hyperpac tuner and it is set to correct the tire size, which it does fine. I have been running shift firmness at #2 (there is Stock and then settings 1-4) I was also running it set to hold the shift points to +200 RPM from 1 to 2 and +100 RPM for 2 to 3 and 3 to 4 (OD). It has always run just fine and honestly it was hard to notice a HUGE difference over stock at these settings. The tuner is also running the "Premium" performance tune, Redline bumped up to 5400 RPM, Top speed limiter raised to 118 mph (not an issue, never even come close). Rear end gearing is set to "Stock" and it knows it's the 4:10s.

 

Never had any issues before, except for once when I set shift firmness to the highest to see what it was like. It was like it was today; Harsh, like I was being rear ended on every up shift whether it was a slow easy one or one at speed under load. That lasted half an hour and I set it back down to #2 and have kept it there. About 99% of my driving is done around town, start and stop, 35 to 45 mph zones on average. At #2 life has been good.

 

The one variable today was weather and I took a 75 mile round trip on the local freeways. Today was a rare very rainy day around here. I saved this for last because I did not want anyone to just jump to the conclusion that it was the wet roadway. I have driven with the same settings in very rainy wet conditions a few weeks ago and all was fine (but that trip was the usual 35-45 mph city streets) Today, en route to the freeway, with the engine still warming up, I thought I felt something on one of the 3 to 4 shifts but it was mild and my attention was elsewhere.

 

Through out the 1st half of the trip, on VERY wet freeways there was a bit of a kick on the 2 to 3 shifts and all the 3 to 4s were like being hit. I even checked the mirror on the 1st couple because there was a lot of stop and go and today would have been an easy day to get tagged. Traffic varied from stopped to sustained periods of 65 mph. I tried making it shift under various loads as well as holding each gear and up-shifting manually. The harshest hits were the very low speed low load up shifts into D. Where the truck is trying to hurry and get you into overdrive. The 2nd worse were the manual up shifts from 3 to 4. It did not make much difference if I shifted while on the gas or backed off before up shifting. The least harsh shifts (and not by much) were when traffic finally broke and I just went from stopped or slow to 65 with the pedal (almost) WFO. There were still harsh "hits" from 2 to 3 (not as bad) and 3 to 4 (bad but not as harsh as the lower speed/load up shifts).

 

Any ideas? Anyone else have these issues with whatever tune they are running? Those that have played around on how much TM they eliminate, has this been an issue? Has roadway wetness been an issue? I would have thought dry roadway would be worse with the slippery wet road maybe somehow absorbing or allowing a harsh shift to spin a bit, lessening the jolt. But why the jolt in the 1st place? (The wet???) For the sake of this discussion, I will stipulate that all those Blackbear and custom dyno tunes are the best. Yay- you win. I'm not starting a "my tune is better thread." And just telling me to get a Blackbear tune does nothing to explain or troubleshoot any of this. I'd really appreciate anything anyone might be able to offer. Plus it gets better.

 

Before driving home, I re-programmed the Hyperpac as follows: I set shift firmness to #1 (one above stock) I did not want to all the way back to stock. I also changed the shift points to +100 RPM from 1 to 2 and stock RPM shift points for 2 to 3 and 3 to 4. The weather and traffic were identical on the way home. The entire way home, I did not have a single harsh upshift. I could not even make it happen on purpose by imitating the above actions. Could this all be over +100 RPM on the shift points and a wet road? I really don't think (IMHO IMHO IMHO) that the change to the shift firmness settings would have made any real difference on any other day of the year.

 

Thanks in advance for any insights you can offer. I know it's a long post but now you know everything I do. Oh yeah, go ahead and open your Christmas presents, or finish Christmas dinner but then I want you all right back here afterwards to get this sorted out. Thanks you guys. Merry Christmas or appropriate holiday wishes to all.

 

Jim

[fbachman]

I am admitting (for the sake of full disclosure here) that I did NOT read the ENTIRE post in detail...

 

Also, I am not familiar with the Hypertech products, but I am familiar with the Diablosport Products.

 

Now, that being said, DS does not offer full TCM support via all of their products, meaning that the tuner does NOT allow for the setting of any TCM settings. They claim to be working on offering that

 

Now, here's what I do know relative to the DS products. There are sporadic reports from users of some of their tuners of hard shifting, much as you describe. There are trannie behaviors that you can tweak via the PCM, then there are things that can only be tweaked via the TCM. DS, at least on the 7194 for the trucks, does not support TCM adjustments, but you can tweak PCM trannie realted settings, such as pre-shift timing and throttle retard, etc..

 

When this happens, it is my understanding that these folks send their tune in, and DS makes changes to the tune to alleviate this situation, as it appears to be highly situational. If I am not mistaken, many of these folks also are trying to incorporate tire change settings. Maybe there is a similarity here.

 

Therefore, I would recommend that you contact Hypertech and ask them what is going on, and if they can help.

 

Another recommended troubleshooting step, if you have not done so already, make sure it is,indeed, the tune and/or its settings. Flash back to stock, and see if the issue goes away. IF it does, then you have certainly narrowed it down to the tune. If NOT, then you may have a different trannie issue going on. You may also try to return the tune to "default" settings and see if that affects things. At that point, you may have narrowed it down to compounding setting changes that resulted in an undesirable result.

 

I hope this may be of SOME help to you. I am afraid I can't offer a whole lot more here.

 

Are you throwing any codes?

[66nova]

Just get a blackbear tune!

 

 

Seriously though, I agree with Grumpy. I would flash it back to stock, drive it for a bit, and see if you have any problems. No problems, then go back and try the tune again. I have 100% of the TM and my truck shifts quick and firm, but not jolting my head.

 

The only time I have had any issues with it shifting harder than I would idealy like is when I take off hard, but then get out of the throttle right before it is wanting to shift. Then bam, it hits hard.

[fbachman]

Just get a blackbear tune!

 

 

Seriously though, I agree with Grumpy. I would flash it back to stock, drive it for a bit, and see if you have any problems. No problems, then go back and try the tune again. I have 100% of the TM and my truck shifts quick and firm, but not jolting my head.

 

The only time I have had any issues with it shifting harder than I would idealy like is when I take off hard, but then get out of the throttle right before it is wanting to shift. Then bam, it hits hard.

 

I agree... as indicated, some of the PCM trannie settings are tweaked in mine---can't touch the TCM with my tuner. Shifts MUCH better than stock. I too can create the very hard shift if I jimmie the throttle just right.

 

I am not sure I would remove all of the TM, even if I could. Given the way mine shifts NOW, I am happy. At least it doesn't feel like I am sliding down a muddy slope when it shifts. It shifts as firmly as I like it to, but doesn't give ya whip-lash as a matter of principle....

[jimlem]

Just get a blackbear tune!

 

 

Seriously though, I agree with Grumpy. I would flash it back to stock, drive it for a bit, and see if you have any problems. No problems, then go back and try the tune again. I have 100% of the TM and my truck shifts quick and firm, but not jolting my head.

 

The only time I have had any issues with it shifting harder than I would idealy like is when I take off hard, but then get out of the throttle right before it is wanting to shift. Then bam, it hits hard.

 

I agree... as indicated, some of the PCM trannie settings are tweaked in mine---can't touch the TCM with my tuner. Shifts MUCH better than stock. I too can create the very hard shift if I jimmie the throttle just right.

 

I am not sure I would remove all of the TM, even if I could. Given the way mine shifts NOW, I am happy. At least it doesn't feel like I am sliding down a muddy slope when it shifts. It shifts as firmly as I like it to, but doesn't give ya whip-lash as a matter of principle....

 

 

Thanks guys. First I am really beginning to see the entire incident as related to the rainy, wet conditions. BUT WHY/HOW? These days are so few and far between that I figured tests like those you suggest would be put off until god knows when. However, it seems we are due for a short but really wet Xmas here in So.Cal. Something like 6" of rain between Wed. and Fri. As a trip over the freeways and thru the toll gates to grandma's house is called for in about 12 hours I will try your suggestions. I hate to return to stock when I just filled up with premium gas today so I could use their premium tune. There actually does seem to be a tiny bit better throttle response etc. when using there 93 octane (Premium) tune over their 87 octane (Regular tune). Of course neither can sh*t in the woods like a Blackbear.

 

*** Remember the problem occurred on a rare rainy day and 1 1/2 hours later, I dialed back the shift firmness and shift RPM points and it was GONE while driving back the same route in the same wet conditions. I realize that w/o out doing as you suggest, I am leaving out a troubleshooting step that removes any sound testing metholidgy. So, I'll try stock one way in the rain and maybe bump back up to where I am now for the trip home and see if there's a difference.

 

Robert you say you "have 100% of your TM and your truck shifts well and firm." Do you mean you have eliminated 100% or kept 100% of your TM on the truck? If you mean removed, does weather affect your shifting at all? Frank, you may know as much or more than I do about Hypertechs. Are you saying you believe the Hypertechs can somehow touch the TCM as well as PCM where Diablos cannot? Are those shift parameters I mentioned (possibly not read 100% by you ) only tuneable via the TCM? I ask because I always got the feeling Hypertech made a decent product but doesn't go out of their way to be special. If so I am momentarily thrilled to know mine does something another brand does not. But, then I just remembered neither of us has Blackbear tunes so we aint scheisse.

 

Seriously, I have sent Hypertech several emails (they listed absolutely no contact info with my product except an email address they ignore) asking some of these questions as well as interesting things like why do I have 2 USB ports, a 2nd smaller OBD ll cable connection and what appears to be a DC in power supply socket? What do they do? How might I put them to use? Not a single response to my emails. I just figure they don't really care much after getting your money. My point is: I never really looked into my Hyperpac and how it works, what all it can do. Now I am even more interested in its details. Thanks again guys. Have a great time however you celibrate the holidays. Hopefully those custom tuners I was hoping to catch with lots of knowledge on this subject are just busy with the holidays or trying on their Dallas BB Tune t-shirts and not ignoring me because I teased them a tiny bit about their tunes. Oh well.

 

Jim