07 Duramax Manual Shift

[rsaint]

Has any body experienced no manual shift. When in M acts like in drive and indicator on 6. Only thing in it is the bullydog economy chip. When on warrenty they replaced tow haul mode switch which was awhile now.

 

[slomo]

if the bully dog changes the shift points it may cause a ratio mismatch which will inhibit the manual shift but i'm not sure how the bully dog is installed and would have to scan it to figure out any further,it also may need a tcm recalibration,but i have no seen this issue since this feature has been out
have you tried to remove the controler and check to see it it works that may br a good starting point

 

[flabbajabba]

I test drove 2 (used)duramaxs that had that problem?(when I was looking) I also was told that only a GM dealer can scan the 06 and up GM's. I tried to get it scanned at Diesel Tech and they couldn't do it. (I didn't buy the truck)

 

[johndeereman346]

I have a new body chev with the 6.0 gas and my manual mode shift switch doesnt work, have to buy a whole new lever to fix it