O5 Expedition overdrive issue.

[mikecynn]

Hey folks:
I have a great running truck with 182k on it after I changed everything under the hood attached to the engine block. Lately though it has a rather consistent problem with the overdrive.
When the truck is cold the tranny runs fine. After it's all warmed up, say an hour or so of back road driving. It will stop shifting into overdrive at 40 to 45 mph where it normally will. I can still get it to shift into overdrive if I accelerate the truck up to 55 to 60 mph, it will drop into overdrive, but If I hit any kind of hill to climb it will chatter or shudder the trunk as it wants to both stay in overdrive and try back down to 4th gear at the same time.

Note: bought the truck with 157k and have never touched the tranny.
I don't know about the fluid changes or if it ever had one. That I
will do if the other problem can be fixed without major repair.

 

[TobyU]

I would certainly change the fluid and filter via a pan drop. Converter shudder feels similar especially when giving it a little more gas on a slight incline. Feels like driving over rumble strips or it can't decide what gear to stay in.

 

[sandeep]

May have issues with slipping O/D band. Does the fluid smells burnt up? Good Luck.

 

[johnboneske]

At that many miles I WOULD NOT change the fluid, if you don't know if it has ever been done?? Everyone has their own opinion, but if you don't know the service history don't change the fluid... The trans may rely on the "crap" in the fluid as a type of friction modifier. Just my .02

 

[TobyU]

At that many miles I WOULD NOT change the fluid, if you don't know if it has ever been done?? Everyone has their own opinion, but if you don't know the service history don't change the fluid... The trans may rely on the "crap" in the fluid as a type of friction modifier. Just my .02

Actually I think that would be the opposite of a friction modifier. I think the friction modified fluids are more slippery not sticky but I certainly know what your are saying about fresh fluid.
The old ones that came with mercon and not merc V, can start to slip with merc V more often than if you use mercon.
Some old timers even strain old fluid and put it back in. I don't go that far.
05 is barely onto merc V days. Still a 4r75w right? They work fine on either but don't shudder as soon on merc V. That is why ford came out with it. Better synthetic more slippery (kinda) fluid to eliminate converter shudder complaints

 

[johnboneske]

Actually I think that would be the opposite of a friction modifier. I think the friction modified fluids are more slippery not sticky but I certainly know what your are saying about fresh fluid.
The old ones that came with mercon and not merc V, can start to slip with merc V more often than if you use mercon.
Some old timers even strain old fluid and put it back in. I don't go that far.
05 is barely onto merc V days. Still a 4r75w right? They work fine on either but don't shudder as soon on merc V. That is why ford came out with it. Better synthetic more slippery (kinda) fluid to eliminate converter shudder complaints

are you sure?? I looked in my book and my 2003 shows Merc V.

 

[TobyU]

are you sure?? I looked in my book and my 2003 shows Merc V.

What book are you talking about? Somewhere right around 02 or 03 is when the owner's manuals started recommending Merc V because that is when Ford stopped making the old Mercon.
You can go back through all the 90s and 01- 02 or so and read the dipstick or the owner's manual and it will tell you to put Mercon in it.
I had a 97 V10 a 2001 and a 2000 with 4r100 in them and they all came with Mercon.