Transmission issues - Ike Gauntlet

[2017HD]

I've been watching several of the FLT videos on the Ike Gauntlet and they are constantly commenting/bashing the gas powered HD trucks for the transmission - both on the downhill and uphill runs. They show a lack of downshifting on the downhill and requiring several brake applications to stay at their 50 MPH. On the uphill they run WOT and complain that the transmission up shifts and allows the RPMs to drift way low before downshifting and then not holding the lower gear.

 

Having owned an 07 2500HD gasser and towed with it, I had no issues with the transmission shifting either up or down hill.

 

Was there a change in programming in the 14/15 time frame that would account for this?

 

Is there something about the way they do the testing max load WOT??

[2016HD]

Lack of Driver input!!

[newdude]

They have problems because of how they run the test. Every test on the Ike uphill involves holding the pedal to WOT and leaving it there. The goal is to go as fast as possible, typically within 5 mph of the speed limit on the Ike. In real world its not all about how fast you can climb that pass, therefore you can use manual mode and then lock it out of those higher gears it shifts into that rob the power.

 

They had similar issues two-three years ago when they tested a 2015 similarly equipped gas HD. But, you think GM has funky shifting, the Ram HD 6.4 they did back in 2015 wouldn't get past 2nd gear I think. The ratio change from 1st to 2nd was so steep that it cut power hard.

[sdeeter19555]

I've been watching several of the FLT videos on the Ike Gauntlet and they are constantly commenting/bashing the gas powered HD trucks for the transmission - both on the downhill and uphill runs. They show a lack of downshifting on the downhill and requiring several brake applications to stay at their 50 MPH. On the uphill they run WOT and complain that the transmission up shifts and allows the RPMs to drift way low before downshifting and then not holding the lower gear.

 

Having owned an 07 2500HD gasser and towed with it, I had no issues with the transmission shifting either up or down hill.

 

Was there a change in programming in the 14/15 time frame that would account for this?

 

Is there something about the way they do the testing max load WOT??

I was told the programming was changed slightly in '11 because people complained the 6spd shifted too much...I asked about this when I bought my '12, cause it holds gears longer than I would like it to causing just a tad more RPM drop than feels right. This might also be partially because of my 3.73s too...

 

But it has no problem dropping gears and holding them downhill as long as T/H is selected and the truck senses the load pushing it. Once locked to a lower gear, it stays there. One thing to keep in mind is a gasser doesn't have the reciprocating mass or compression of a diesel, and dropping gears doesn't give the same engine braking effect as a diesel (even one WITHOUT an exhaust brake), they just tend to wind up.

 

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[Cowpie]

There is good reason why GM included a manual mode. No transmission can adjust for every variable. My pickup spends most of its time in manual mode, and given where I frequently drive, hardly ever sees 6th gear.