Hi guys i have a 2006 screw 4x4 with a 5.4 engine and with 36000 miles. My problem that i am having is I repared my trasmision twice already, the last time the mechanics replaced the fluid of the tranfer case 4x4 and now when i reach about 50 miles to 60 the truck star making a weird sound like a wining sound, i ask the mechanics what oil he used and he told me Do3 something like that. I went to the manual and it say Motorcraft MERCON ATF, i went to the dealer and they told me to use MERCON V as it is on the trasmission. I dont know what to do? If i should use the MERCON V or MERCON any imputs guys will apreciated.

 

MerconV is the current Ford spec. Have the shop that did your tranny work drain and fill it with the proper fluid.
They didn't put a heavy gear oil (as used in the differentials) in it did they?

 

Bindernut is not on the tranny that they put a different oil.It is on the tranfer case(4x4) thats my dilema? what kind of oil is it, like i said on the manual say it should be MERCON ATF but the dealer told me to use MERCON V. you know how it is dealers sometimes full around.

 

Yup...the transfer case also uses ATF. The latest Ford spec call for MerconV to be used in both the transfer case as well as in the transmission.

 

Any ATF that meets Mercon specs is fine for the transfer case. Mercon, Mercon V, whatever. If anything else was used, get it changed. Have the shop show you a bottle of the stuff they used and read the label. If it's ATF and says Mercon on it anywhere, it's fine.