Can someone help me determine the type of transmission i have in my 1999 F150 Extended Cab 4x4 with a 5.4? How do i go about determining which it is? Is it stamped on it somewhere or can i tell by some sort of trademark feature? Thanks.

 

Hi and welcome to the forum

The easiest way is to check the code on the vin sticker in the drivers door jam.
More than likely it is a 4R70W.

U = 4R70W
E = 4R100

Jimmy

 

How much tougher is the 4R100 than the 4R70? I haven't seen any of these fail but I haven't seen any with over 100k come in for maintenance either.

 

I believe that the 4R100 is supposed to be better, it just depends on what it comes in. The F150 4R100 isn't as strong as the PowerStroke 4R100. The Lightning uses the F150 4R100 casing with PowerStroke guts in it.
I haven't really seen either fail. You might read up in the tranny forum for better details.