Two problems related to transfer case have been reported for the 2004 Ford F-150. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Ford F-150 based on all problems reported for the 2004 F-150.
I bought the 2004 fx4 F-150 super cab in late 2005 with 25000 miles on it. I purchased a $1400 extended warranty from an independent company through the Ford dealership. After the first few months I noticed a grinding sound under the truck that sounded like a few ball bearings rolling around quickly in a metal bowl. It would last about 5-10 seconds and then I would not hear again for a few months. After about the 5th time this happened I took vehicle to the Ford dealership, and they could not duplicate the problem, so nothing was done. The next time this noise was heard I quickly turned on the 4x4 high via the switch on the dashboard and the noise went away immediately. I could do this every time after. This was telling me it was somewhere in the transfer case. So, last week around 60000 miles the transmission started grinding in traffic, slipping, and giving me a transmission fail indication where the odometer was located , and a flashing overdrive off. This happened for about 10 minutes until I could get off the expressway, and exit into a gas station parking lot. I thought for sure the transmission was going to blow out at any moment. I turned off the truck, which reset the transmission fail alarm, put the truck in reverse, which made a loud slamming noise. I then put it in drive and was able to drive home with only grinding noise in first gear. I waited 2 days ,and then drove the truck to the dealership 40 minutes away without any problems . After a day in the s repair shop they pulled the pan and it had metal shavings everywhere. They called and told me they couldn't figure out how I was able to drive to the repair shop. They found some bad seals and a vacuum pump/solenoid in the transfer case, the transmission was gone and was completely replaced. All the software has been updated, which I have heard can cause the majority of the problems. It would have cost me around $6000 if I didn't purchase the complete warranty.
The vehicle accelerated when pressing on the brakes. Contacted the dealer, they did some work to it and said it was a diaphragm, and they fixed it. This worked for a while and then it started doing the same thing again. This was August 1, 2005. Noticed it made a groaning sound and shook. They replaced the transfer case, and it hasn't made the sound since then. When standing at stop it surged, gave a little jump/pulsated and touched the brakes. It happened intermittently.