hey all,
i've got a '99 Lariat SC with the 5.4L and i believe the 4R100. i was just curious as to the reliability of these transmissions in terms of mileage. i have a touch over 79,000 right now and the truck runs great (knock on wood), but i was wondering how others have fared with this configuration. thanks for any replies.

 

I guarantee your 4R100 will outlast my crappy 4R70W. I'm at 74k now and it already drags through shifts. I'm gonna' change the fluid (again) soon and we'll see what that does.

 

I was under the impression that most (if not all) F150's had the 4R70W. Check your door code to see which transmission you have.

Either way, they are both good transmissions if built correctly. The stock 4R70W isn't nearly as strong as it could be. If it is rebuilt with the extra clutch plates and so on it will handle a lot of horsepower with no issues.

-Don

 

Just to be clear: The 4R100 is definitely available on the F150, it just isn't common. It was found mostly on California destined F150's (For emissions or some such silly reason) and on Lightnings and diesels.

As for the codes:

U = 4R70W
E = 4R100

-Don

 

the 4R100, was never mated with the 4.6L.

on the positive side, our 97 Lariat (4.6L) has an original tranny in it. We are now about to turn 200,000 miles. We've change dteh fluid every year/15,000 miles.