Is there going to be an announcement on December 8th or is this yet another tease?

 

Wow. 4.56 and stock tires. What rpms are you running st 70? You changing tires?

 

The 4.56s aren't bad at all on the highway. At 70 mph, I'm only seeing 2300 RPM. At 80, I'm around 2700 RPM. Remember this is on the stock 32" 4WD tires. If I had a 2WD, I would have gone with a 4.10. I am still seeing 15 mpg on the highway at 80! Around town, I am getting nearly 1 mph BETTER. The truck actually accelerates now, especially with a 6,000 lb trailer. I downsized to my F-150 from a 04 F-350 w/ the 6.0L PSD. I had a box (module) on the 6.0L, which added over 200 ft/lbs at 2,000 RPM, so pulling a 6,000 lb trailer at 70 mph, turning 2000 RPM was a dream. The truck would pass with the trailer on a two lane road WITHOUT having to downshift or even unlock the converter. SO, you can imagine the disappointment going from that to the weak power of a gasser. The 4.56s helped improve this weakness a little....at least I can use O/D at 70 mph now when towing.

Maybe it is a balancing issue, but my guess is just a bad production run or production period on them. Maybe they weren't handled properly before install and had minor bends in them? I'm not sure. My truck was smooth at 90 mph too even with the 4.56s, but fall down to 80 and it was bad, so it only occurred at specific driveshaft RPMs. Now with the carbon fiber shaft, the truck is silky smooth at ANY MPH.

 

I would call your Dealer the following week. A Ford Engineer from the KC truck plant said it is due to dealers the 8th. My service rep said it was due the first two weeks of December.

 

I don't think the problem is with the length of the driveshaft but more the weight of it combined with gear size. Read what DonsFx4 said above. He had the same problem. I'm thinking of getting the carbon fiber driveshaft and a lighter muffler. Then I want 4.30 gears and superchip tuner. Just think how fast that truck will roll lighter and smoother.

 

Robert,
I am assuming with the 4x4 you must have a single piece driveshaft on your Supercab. My 2 wheel drive truck has a two piece driveshaft. What are my options as far as carbon fiber go?

 

Chinstar,

Ahhhh....good info!!! I didn't know that. I assumed that all F-150s used a one piece. You've got me stumped on the 2WD. It all depends on which one may be causing the vibration. The rear portion is probably the longest, right? If so, and your vibration is speed sensitive (not RPM) and happens from 45-60 mph roughly, it's 99% most likely your driveshaft. Typically 2 piece driveshafts connect to each other at the carrier, so they can be replaced independently. I would contact PST (www.pstds.com) to discuss at least an aluminum replacement. It may be pricey since you have twice as many U-joints.

 

Hey guys didn't have a vibration until I got on here and started reading about other people having them and then at around 3000 miles I started getting one during acceleration between 50 to 70mph and then it goes away once I come up to speed. Called my dealer yesterday and they said bring it in because they new all about the vibration in the F150's coming from the driveshaft and would take a look at it.

I have an appointment at the dealer for Saturday. My sales guy said that the Ford Factory guys told him it has to do with the two part drive shaft and they are going to have a fix for this.

I will let you all know what I find out.

 

Fords new tsb will address the drive shaft.. No need to have one build it seems the culprit in the drive shaft (ones vibrating) is the u joints and the carrier.