05 duramax trans limp mode

[Transamjoe]

I have a 05 dually with I believe efi live It goes into limp mode when trying to pass its happened towing and not. I haul a 16,000 lb toy hauler if I have the program on 2 it’s fine but on 3 at 55 mph and 65 it will go into limp mode if I ask anything if the throttle. Has anyone else experienced this I’m leaning towards the program

 

[TheBac]

Im leaning toward a transmission rebuild...

Your tune 3 is probably too hot for towing on a stock transmission, and by the sound of it you've already hurt it.

BTW, moved to Trans Talk section.

 

[2004LB7]

We need codes, but like Ton said, probably transmission slipping

 

[kidturbo]

Is typically converter slip on the shifts with the LLY. They had a weak converter, and I've had to turn down a couple truck for buddies in the past. Towing a load up hill, little bit of throttle, and bang straight into limp mode.
So as stated above, get the codes first. Then decide if warrants a rebuild while your swapping the converter.

 

[Transamjoe]

P0735 plus various others. My last truck I installed a ppe and built the trans on a 03 with 289,000 miles and towed this fine. I bought this 05 which already was used for towing it had only 165,000 miles but I think the previous owner dumped it cause of the trans. I had the truck in the trans shop they said it was fine think I need anther shop I was gonna remove the efi and install the ppe but after your feedback believe the trans needs some love. Thanks

 

[Transamjoe]

P0735 plus various others. My last truck I installed a ppe and built the trans on a 03 with 289,000 miles and towed this fine. I bought this 05 which already was used for towing it had only 165,000 miles but I think the previous owner dumped it cause of the trans. I had the truck in the trans shop they said it was fine think I need anther shop I was gonna remove the efi and install the ppe but after your feedback believe the trans needs some love. Thanks

The first time I experienced this the truck was empty on program #3. While towing the past few times it was in #2 with no problems. Think I’m gonna try a converter

 

[kidturbo]

Majority of ones I've seen do it are just the converter. Usually up in the hard 4-5 shifts. However was riding in my buddies 05 at local dirt drags a couple years ago, and his smoked 3rd gear in a run. Boiled off some fluid previous pass, and fluid smelled smoked. So we hit it one more time for good measure.. 3rd wasn't there any longer...

 

[PureHybrid]

Local kids that run tuned trucks and stock transmissions end up having burnt c2 and c3, with some heat marks on the c4 steels. Even if they claim the transmission never limped

 

[Bdsankey]

I would get the codes but based on symptoms it seems like it's time for an overhaul.

The weakest clutch pack in the transmission is the C3 from the factory. They have 4 friction disks (8 surfaces) and are worked very hard. They come on for the 3rd gear shift, off for 4th, and back on again for 5th. This means they have very minimal cooldown time between heat cycles and tend to burn.

At OEM power levels this typically isn't an issue but with added HP/TQ from tuning etc it becomes an issue quickly.

 

[Transamjoe]

Thank you all for all your help. I already had the truck at a transmission shop they claim the trans is fine but I think they are wrong I am gonna start with a new converter and go from there also I’ll keep the tune down

 

[Bdsankey]

Thank you all for all your help. I already had the truck at a transmission shop they claim the trans is fine but I think they are wrong I am gonna start with a new converter and go from there also I’ll keep the tune down

Let me know if you need any help!

As for converters, the only concern I would have is IF it really is the trans failing you will just be putting debris into a brand new converter which doesn't usually end well.