Random Downshifting 2010 E450 SuperDuty

[goldfinger]

My 2010 Lazy Daze C Class E450 Super Duty with Triton V10 randomly downshifts on flat terrain when cruise control is on and trans is in "drive" mode (NOT Tow/Haul).  I have to pull over to the side of the freeway, shut off the engine, then start it again.  I've discussed this with my local Ford dealer but they look at me as if I am an old grey haired dummy.  I'm a former Parts Manager for Cadillac and Harley Davidson, so I'm a bit more knowledgeable than they give me credit for, despite the fact that I'm a 62 year old woman. I also have a 1998 C Class on a Ford E350 chassis with a Triton V10, that I bought brand new, that has never had this "random downshifting" problem, so I do have plenty of RV driving experience.  Anyone experience this also? Thanks! 

 

[znerf]

This is fairly common with the newer 6 speed transmission it does not take much of a grade in the road or a headwind for it to down shift. Most of the time I tow in 5th gear. The MPG on my truck is only about a .2 or .3 difference. Your older Ford had a 4 speed trans and was not controlled by the Computer the new one is. Have the FORD Dealer see if there is a upgrade to the computer there may be a upgrade in the service bulletins (TSB) 

 

[goldfinger]

Thanks!  Never occurred to me about the "head wind"!  With the new computers on vehicles, I feel like I'm driving "Colossus, The Forbin Project"! I check online for service bulletins all the time, since I found one regarding poor engine performance that I complained to my Ford Dealer, El Cajon Ford (they shrugged it off) and I brought it to their attention with the service bulletin #. 

 

[SkyWriting]

Anyone experience this also?

Yes. A great repair shop is hard to find but a joy to work with.  Walk out and shop around till
you find what works.  My favorite service man almost tastes the oil when I bring in a car.  He
examines the oil cap like a x-ray technician would check for dark spots on your lung.

 

[driftless shifter]

Yes. A great repair shop is hard to find but a joy to work with.  Walk out and shop around till
you find what works.  My favorite service man almost tastes the oil when I bring in a car.  He
examines the oil cap like a x-ray technician would check for dark spots on your lung.

He's looking for condensation mud in your oil. If it's there, it indicates short trips with a cold engine, never warmed up, driving style. That kind of driving is hard on a drivetrain, causes numerous out of tune type of complaints. Your mechanic sounds like a keeper.

Bill

 

[terry735001]

some thing to add  on used GM RV

cruise control is run by the TAC  module    on newer like 8.1l  or so 2002 up

if the wight of the RV is not update to the right TAC you well all ways get a MIL light ... check engine light...

i am finding it hard to find a new or used TAC module for my RV  so i could installed a lower GVW module but my cruise control would pop the engine light all the time as the
car/truck would not get up to speed fast / or to slow 

so what i am trying to say is  .. well not 100% sure on ford ..  but if any thing was wrong i am sure your light would come on  saying so

O yeah  too add  on used / new    if a guy  LIKE me on the road could not find the right part number i would install what ever i  needed to get back on the road 
to any one with a RV that dos not like cruise control  this could be why

all so with a high towing trailer/load with cruise control on can do the same thing some times 

just a really good note to add i guess