Jonblarc7

So I have a post on HP tuners about this but I thought I would put one on here since ya'll have more experience with trucks.



In my denali my trans shift fine without Tow Haul mode on. But as soon as you turn it on it goes all to hell and I'm so new to this I don't know where to start.


The problem

If I'm cruising down a flat road at 45 mph and turn on TH mode. With out changing throttle position or going up or down a hill. It immediately down shifts on gear to about 3,000 rpms then drops one more gear and now I'm sitting at 4,500 rpms just cruising down the road. And the down shifts are violent.

I pull a pretty big wakeboat and I can use TH mode at all. I have to manually shift it which it does fine, it's just annoying.

Jonblarc7

So after saying all that it was suggested to change all sections under Pattern A back to stock. So I found a 2009 denial stock tune and switch it around. then drove it around the block in TH mode without pulling anything and it seem to be working great.

So I hook the boat up yesterday and start to the lake. I made it 2 miles from the house then next thing I know. It starts dropping gears out of no wear and I'm sitting at 5000 RPMs before I could get Tow Haul off. This was on a flat straight piece of road with no change in throttle input.

I pulled the boat the rest of the way in manual mode and just selected the gears and it did great.

Not sure what to do now. Maybe something is wrong with the trans and in TH mode it senses it and causes it to down shift.


I'll put the last tune up when I get home. But the tune and log after using the bluecat tool is on the HP tuner thread.

Jonblarc7

Here is the last tune I used that worked for 2 miles and then started to down shifting with the boat. From what I've read pattern a is what I should have changed for TH mode. So I guess my only option is to set the whole truck back to stock and see if it still does it. And if it does I guess something is wrong with the trans.

GR8TALK

I'm gonna look at the file shortly but wanted to ask if you have any tire size or gear changes done. Do you also have a copy of the stock file?

GR8TALK

Start over with the trans tune. After looking at your history logs and comparing your base file to your current. I have come to the conclusion that you have the part throttle pattern B shifts all kinds of wacked. The only thing you didn't change from your base file was the part throttle 1-4 up and 1-4 down under the table labeled Pattern B in the Pattern B part throttle section of the shift speed tab. You might want to try adjusting that table using the same methodology as the other tables you changed. But if it was a vehicle I was tuning I would start from scratch. Hope this helps.

Jonblarc7

Thanks GR8talk.

When you start over do you just copy and paste to all the tables from a stock file. Is that the best method.

GR8TALK

You can copy and paste but I like to load the stock calibration and edit from there. If you go to the edit tab>view/change calibration history it will show the date and time stamps along with what was changed. Go to the bottom of that where it says base and open that file. Write it and go from there. Typical methodology is to slightly raise the low throttle position upshift speeds by 5mph or less from 0 to 50%ish. Then smooth the table out from left to right so upshifts occur at higher speeds as thorottle increases. There is almost never a need to raise shift speed above 75% unless you have changed tire size or gear ratio and or desire a higher wot shift in regards to engine speed. Then make the exact same mph changes to the down shift tables relative to gear so not to send the tcm into a frenzy. Usually 3-4mph is good from 0-50% tps on the up and down shift speeds. Highlight the entire table for all shifts both up and down from 0-50 and add x then make sure table goes up from left to right. Load it and evaluate. After 50-100 miles it should be adapted and you can correct to feel. Don't change single cells as this can result in odd behavior. Patter B should be trailer mode. Normal and Pattern A I like to keep identical.

FFDP

iTrader: (2)

It's faster to do it a different way with no need to ever write back a whole stock calibration and start all over on both sides.

Open your tune and then use the compare feature, choose a stock file and open it in the compare. Click compare again, then comparison log. Then click the "minus" icon as all the tables will be open, then you are left with just a tab saying engine and transmission. Right click transmission and select copy over all differences.

And that's it, you have your engine side the same way it was and all your transmission tables are factory once again.

Jonblarc7

Thanks I'll give that a try tomorrow before I head to the lake.

The main reason I bought HP tuner is to try and fix this TH problem. The guy that tuned it originally just didn't act like he had time to mess with it.

So I left with trying to learn it a fix a problem.

So I'll take ant advise

Jonblarc7

Got the trans tune back to stock.

It rained today so i didn't pull the boat but it acted better just driving around in TH mode with out pulling the boat. So I'll leave it on the stock tune until Thursday night. I alway got wakeboarding after work on Thursday's.

But man the stock trans tune is a lazy bastered!!!!!