Most of you know I've had several issues with the transmission in my 06 F150 CC 4X4 with the 5.4L. Well, took it to the dealer for the 4th time and I was finally given a decent rental. It is a 06 F150 CC 2wd with the 4.6L V8.

I'm surprised at the amount of power it had compared to mine. I know this is an apples to orange comparison, but it doesn't feel any slower than my truck. In fact the power delivery is so much smoother. It pulls better above 3000 RPMs that my truck. Oh, and I don't have a problem with the way the transmission shifts.

Now, I think my truck is losing a ton of power through the transmission. I might have it dynoed when I get it back from the dealer to see if that is the case. What kind of numbers can I expect the 5.4L with 4X4 to put to the ground? I'm thinking somewhere around 210-230hp.

 

220-230hp should be about right for a stock 5.4 to put to the ground.

 

Thanks I think there's definitely something wrong with my transmission. Doesn't get that good MPG compared to what some of you have been reporting. I get 13.7 mpg at 70-75 on the interstate. I'm not complaining about the gas mileage because it's a truck.

The 4.6L in the F150 reminds me of the 5.0L V8 I had in my 2001 Explorer. What kind of data can be obtained from the dyno runs that might indicate something is wrong with the transmission?

Also, when mine is cold it runs really rough when accelerating. One time I saw some black smoke coming from the tailpipe. Do these trucks run really rich when you first start them up? This goes away as the engine warms up.

 

13.7 at 70+ isn't that bad. Highway mpg testing is done at like 55. When you start going over 65mph mpg goes strait down prety fast.

Black smoke is unburned fuel, and my truck doesn't do it but I have a '06 4.2.

 

Id be pretty upset if I had an '06 F-150 and only got 13.7 mpg on the highway. That thing should be pulling 16-20 mpg on the highway.
The reason why the 4.6L feels smoother is probably because its just putting out less horsepower and torque.
A 4.6L should be pretty similar to a 302 in terms of power. The 4.6L is a good engine, but I personally dont see why you would want a 4.6L when you could have a 5.4L that gets the same MPG and has a lot more power. If you are going to go with a V8, you might as well go for the big dog because the fuel economy is going to be the same either way.

 

I already have a 5.4L in my 06 Lariat CC 4X4 with the 5.4L. My truck doesn't seem to be putting down as much power as a 2wd 4.6L CC rental I have now. My truck is in the shop getting the transmission worked on for the 4th time in 2 months. I know 4X4 will take some power away, but damn the 4.6L might outrun my truck right now.

Maybe, Ford will replace the transmission instead of just replacing crap. I'd feel better if I got 15mpg on the highway. The poor mpg and after driving the 4.6L made me think something has to be wrong with the transmission in my truck.

 

If you rented a 2007, They increased the HP to 248 for the 4.6L. I have one, the MPG is great. But again I am only using it during the weekend, and I drive 95% Hwy 5% City. It is not as powerful as the 5.4. The other thing, the 4.6 got some kind of award and is rated top 5 engine worldwide in its category. I forgot where I read it. If you do occasional hauling and towing, once in a blue moon, the 4.6l is the way to go, but you got have the truck equipped with towing package and LS diff.

 

This is precisely why I went with the 5.4. Negligible difference in economy compared to the 4.6 and more power.

 

The rental is a 06 F150 with 26,000 miles on it. MY truck that's in the shop even has the 3.73 LS differential. This rental probably has the 3.55 differential. I haven't confirmed this yet.

All I'm saying is that my 5.4L seems to be lacking in power. Or, the transmission used on the 4.6L is more efficient.

Once again apples to oranges comparison 4.6L 2wd vs 5.4L 4X4. I've driven both and the 4.6L feels a little more perky than my 5.4L.

 

Adaptive strategy is why your truck seems sluggish. It's the PCM learning your driving style, that's why the tranny seems so slow to shift.

 

If the 4.6 is stronger than your 5.4, then something is definately wrong with your truck. I recently had my truck (5.4) in the shop, and they gave me an otherwise identical truck with the 4.6. Right from the get-go, I could tell a significant difference; my 5.4 had more power. I nailed the 4.6 from a stop, and it was pretty slow compared to what I'm used to (my truck).

And as far as the tranny being a big source of power loss, we (5.4 owners) have almost the same tranny as those with the 4.6. The 4R75W is just a little more beefed up than the 4R70W. AFAIK, there aren't any major internal differences between the 2 that would contribute to a significant difference in power loss. Now I have never driven a 4x4 5.4, so I also may be comparing apples to oranges... But either way, a properly running 5.4 IS stronger than a comparable 4.6.

 

My tranny has had problems since I had 6000 miles on it. It's been rebuilt 3 times at the dealership and I just took it to the dealer yesterday for the same problem. I'm ready to Lemon Law my truck. This is the last chance for the dealer to fix the problem.

I have a 1-2 gear hard shift and sometimes the transmission slips pretty bad. So, I think I've had a defective transmission since I bought the truck that's causing poor mpg and loss of power from the 5.4L V8. Yes, I did test drive the truck before I bought it. Maybe, it worked right then.

 

Yeah, that's definitely something else. I did notice mine getting sluggish though after time, and when I got a reflash of my PCM the truck was instantly more responsive. But that is completely different than what you're saying I admit.

Sorry you're having so many problems with your tranny.

 

Well, guess I'm gonna go get it dynoed when I get it back from the dealer. I'm sure the engine is fine, but I have serious doubts about the transmission. It has felt different every time I picked it up from the dealer.