From how you explained the way you drive towing, I can confidently say it's your driving while towing habits.
When towing anything manual shift, never put it in drive, always use towhaul, NEVER allow the trans to shift into 6th gear.
Maintain no less than about 1800-2100 rpms on flat ground, 2200-2800 rpms on grades max 3000 rpms for short periods to get up that big grade.
Your lugging the engine, which is not good on any engine.

Using drive while towing the trans is searching for the right gear and can't find it, so it's going back and forth thru the gears.
This is also why your trans temps are running high, the Allison is smart but not smart enough or quick enough to keep up when towing.

Your coolant temps are probably getting pretty high as well.

 

I'm not in drive while towing ever I'm always in tow mode manual 5th so it's not my driving habits. The shifting back and fourth is when I'm in drive not hauling anything on cruise control at 120km/h. My Rpm is at about 2000 on flat ground and still wants to hunt for gears and then going up hills will down shift to 4th revving at 3200. So I belive their are other issues if I can't maintain speed when I'm not even towing

 

When in hauling the trailer in tow mode manual 5th when it drops to 4th gear i can have it right to the floor on a small incline and still lose speed fast and rpm fast. If the truck can't hold 120km/h empty on cruise control how can it tow? When towing I also never use cruise control incase your woundering.

 

My computer crashed so I can't post the video I made yesterday of it hunting gears from 6,5,4,5,6,5,4,5,6,5,4 and so on while I'm not hauling on a 3% grade at 120km/h

 

I'm using my cell phone and not sure if their is another way to post video on these forums for mobile use.

 

Try maintaining the rpms I suggested thruout your gears, when the rpms start to drop below my suggestions then drop it another gear.

You might be having other issues, but you have to keep up with the rpm demands on grades.

When your not keeping the rpms up even though your in manual, the trans will start searching.
Even empty pulling grades you still might have to manually downshift, and it's hood that your NOT using the cruise control while towing.
Maybe on flats but you have to be on top of things before hitting the grades by keeping the rpms up.

To clarify you did say in post #1, 5th, 6th, 5th, 4th that's not manual shifting to maintain the proper rpms.
NOTE: I just re-read and noticed you said empty.
Also what's your definition of a small incline ?

What HP level are you running on your H&S Mini Max tuner ?
Is your truck still stock or deleted ?

If you still have issues, I'd find another shop to check it out.

 

3 % grade really ain't that small IMO even empty.
When any vehicle trans starts to hunt for gears, it's time to shift into M and manual shift and keep the rpms up.
It won't hurt it will be in the gear you was in.

As far as posting pics using a cell phone, is easy, your pic is automaticly saved in your phone, post using "go advanced" when you want to upload pics look at the top middle of the page, click on the paper clip, you'll have the option where to get the attachment from, select the one you want, then select upload.
It will/should be in your post when you preview it before you submit.

 

Thanks for all the info! I did try going into manual befor on a hill when it would go from 5th to 6th a few times so I figured I'll go manual 5th I figured it shouldn't down shift at all I was wrong it will then go 4th to 5th and repeat instead of 6,5. My truck is deleted and I'm running the tuner in tow witch is 70hp gain I believe I don't go out side of tow setting as then my truck blows black like crazy it might as well be a ford haha. Our grades around hear are steep we have hills in town that 7-10% and our highway has some very steep well over 20% so 3% would be a hill in the road that you hardly notice if I'm reading this chart right that's only a 5deg angle I may be reading the grade charts wrong but it's a hill maybe a mile long and I'm sure a 14yr old kid can peddle bike up it easy. I have it now at GM and hopefully they will find somthing the other shop didn't.

 

Sounds like you have tuning issues or a boost leak that opens up intermittently.

BTW an easy way to get a rough idea of grade % is to remember that 45 degrees is 100% grade.

 

I agree I thought it was a tunning issue with my other programer so that's when I bought this H&S one and still have issues so not sure if maybe it's something in the factory computer someplace? Okay then are grades are even steeper in parts then I thought thanks for that tip.

 

Hotter tunes than stock....usually will expose existing problems that were there before you altered it.
Changing tunes (as you've found out)...won't fix the original issues, lacking in fuel and/or air, which will screw with the trans shifting.
Do you have a boost leak? Have you tested for leaks?
Is the pressure forcing open the EGR under boost?
Are there leaks in the fuel system, sucking air?
etc.

 

Even though your in 5th manual the trans will downshift on its own to the next lower gear it's because your going to slow in that gear.

If your in 5th manual and it downshifts to 4th all by itself that means your going to slow and the rpm's are to low.

I'd be curious as to what your rpm's are when this happens, my money is on they are to low, for that heavy truck to keep up.

Just try what I suggested on keeping the rpm's up, and that means in all gears not just one.

Once the rpm's drop to the lower #'s I suggested then it's time to downshift.

This is why the places you had to check it out, and why there're saying they can't find anything wrong.
Except for what I mentioned in my post #2.

 

I also add you can be at complete stop, select 5th in manual, the trans will upshift one gear at a time to 5th, then when you start slowing down it will downshift one gear at at time to 1st when your at a stop
With 5th gear still showing on the selector, this is done all by itself.
It's when your towing you need to keep on top of everything with the higher rpm's.

 

Yes, I read that, but he does drive in hilly areas.
I also missed his rpm's mentioned in post #3, my bad.
Also what you mentioned could also be a problem.

mx_master,
Do you have any gauges/monitor considering your tuned, that would be a wise investment.

Just about everything Hook'em mentioned you would be able to monitor with something like the Edge Insight CS/CS2 or CTS/CTS2 anyone of the 4 monitors mentioned would help educate you on what's going on.

 

Okay thanks a lot for all the info you guys. I have no way of getting more data at the moment. I did hear back from the GM dealer they said they the only issue they found was my seals are leaking in my intercooler I'm not sure now much boost the stock turbo is to put out but the highest mine has gone is 25psi that's what I'm seeing with the H&S. Other then that they have not found a single issue with my truck. Ill take a look at those other programmers you guys mentioned as well.

 

Stock engine boost is around 25-26, well mine was anyway.
Depending on your tune, I would think it would be a little higher.
You might contact H & S Mini Max and ask if they increased the boost in the tunes.

My 2 mild EFI tunes they are around 15hp & 25hp, I'll get about 28-29 max.
My 40hp & 60hp ATP tunes 31 max, my DT tunes 40hp & 60hp, 29 max.

My small boost line to my mechanical gauge had broken off, caused by the dealer tech leaning over in the engine compartment, my max boost was 15.
This is to just give you a idea on how such a small broken line would affect on how much boost you would loose.


If your boost is still around 25 when your at 2800-3000 even 3200 rpms you reported on your post # 3, then I don't think its a loss of engine power, your boost would be much lower.
My thoughts lead more to, your trans is having issues.
Converter slipping maybe ?

I don't know what pids the mini max monitors, but real important one's IMO is EGT's, Boost, Coolant and trans temps, Fuel Rail Pressure, Engine oil pressure.
The only one I have found to be correct on your DIC, is the trans temp.
There are many more available pids to monitor on the Edge Insight.

 

Thank you all for helping and giving ideas. I defiantly now need to get another programer just for learning more on what the truck is doing. Just picked it up from the shop and it's running great! Some how the orings on the intercooler pipes were gone so I was only building 23-25 pounds of boost now I'm back up to 35psi went back to that hill and now only shifts down to 5th to maintain Rpm.

 

Another programmer won't tell you much, unless you went with a Edge programmer that has the insight.
But you won't be able to delete stuff with any of the Edge programmers.

What most do is EFI for tuning with the Edge Insight gauge/monitor only, no tuning with the Insight.

If your happy with what you have for tuning then why change, just try to figure out a way to monitor more stuff.
Maybe someone running the minimax might have some suggestions.
I think the minimax plugs into the obd2 port (not sure) if so you might be able to use a obd2 Y to use both.

I had a Y on mine for a while with the Insight plugged into one side but nothing on the other. My Insight worked just fine.

 

Stuff does have a tendency to wear out overtime.
Glad you got'er fixed :thumb

 

Okay yes it plugs into the obd2 port. Okay so the insight isn't really a programer then just a tool to monitor what the truck is going then?

 

:thumb

Now, Edge does have programmers with the Insight, in the $800+ range, no deleting offered.
Where the Insight gauge/monitor only, is around $350-$450 depending on which one you like.