2013 3500 1 Ton Dually / TRANSMISSION SLIPPAGE

[Fish On]

I have a 2013 3500 dually with 6.7 & 6 auto transmission.
Have a 100 gal tank in the bed truck gross is 9600
I pull a Hallmark 53' triple axle gross is 24000
I was getting 12 mpg and at 45000 miles the trans would slip and i would have to stop.
I shut it down for 2 to 3 minutes then restarted and it would take off. I was on cruise when the slippage happened.
My mileage dropped to 8 mpg?????????? Dodge said they can't find anything wrong Any ideas what the problem
might be? Thanks for looking and any ideas you might have.

Fish On

 

[transe]

What fault code(s) did you have? So it only slipped one time, and now it runs OK? No more CEL / limp-in? Any active faults now?

 

[Fish On]

No fault codes / it has done it 3 times always on cruise and going up a grade.
Each time was able to pull over and shut the truck off / 2 or 3 minutes later started it up and took off.
No limp in or faults now.

Thanks
Fish On

 

[transe]

So how do you know the trans slipped? Did you get a CEL? Was the trans acting like it was in limp-in?

I would suspect a bad Torque Converter Clutch (TCC), but that should give you a CEL and a P0740 fault code. That would also explain a decrease in fuel economy.

 

[SnoKing]

Aisin or 68RFE?

 

[DonFitzwater]

If she slips, it'll set a dtc and go into limp mode.

 

[Fish On]

It makes sense that the the TCC is slipping as the rpm's increase as the truck slows down.
Thanks for the insight into what might be wrong. This will help me when I go back to the dealer

Thank Again
Fish On

 

[Fish On]

Thanks for your take on my problem this will help when I go to the dealer next time.

Thanks
Fish On

 

[bigblock_doc]

When going up an incline take it out cruise. It will downshift and try to make up speed.
Manually downshift and upshift, easier on the trans.