This is the second time this has happened to me in the last wo weeks, when driving down the highway with the 120hp tune in traveling at about 65MHP the truck automatically goes from overdrive and downshift and the check engine light comes on, then it will not allow me to put the tranny in reverse at all. Anyone else have this problem?

Could be your NSBU switch. (Nuetral safety back up)

what gear does it downshift to? Maybe you're limping the tranny.

when i am at 65MPH just cruising it goes from about 2000RPM to about 2500RPM at 65MPH......I am not sure what it is and its the second time it has happened now, and both times were while on the highway about 65MPH, i can say i do drive the truck very hard, but the times this occured i was not full throttle or really beating on it?

And yes it was always in overdrive, so is that prob limping the tranny?

Thanks for the replys

-Ltrain

I bet it happens when you start to put you foot in it................. If this is the case you are sliping 5th gear and the transmission is going into limp mode to protect itself. You need to pull over and shut it off for about 1 minute. Restart, then see if you have all forward gears. If it's locked in fouth you will need to repeat the process for a total of three times for the TCM to reset itself. The vehicle must move forward during each resart for it to clear the code. Time to upgrade the transmission and converter.

Thanks for the help.....now if i run the 40hp tune for towing, will I be ok, or is there permanent tranny damage?

Also what yould be a safe fix for this...Converter and shift kit? if so who would you recomend and possible price to buy parts+ average cost of install

thanks

-Ltrain

I would say you are limping your tranny. As soon as it jumps out of OD, throw the shifter to neutral for about 10 seconds then put back in OD and it wont fully limp and throw a code:o . You should be able to run the 40hp tune with no problems.

I would say that you have definitely done damage to your tranny. The fix is definitely to upgrade the tranny. Each time you limp it, it will become easier and easier to do. You should be fine with the 40 Hp setting, but get that tranny upgraded and you will never look back. Then the stacking can begin. . .

check out www.suncoastconverters.com or www.ttspowersystems.com for some prices and options. Install isn't cheap but depending on where you are, there might be members that could help you do it yourself. . . otherwise I think around 1200 to do a SCII install (don't quote me on that, just a ballpark).

Dennis

or http://atsdiesel.com/index.asp

Dennis