This afternoon, after having driven my truck around town in the morning, I started it up to take another quick trip. First I noticed the whining sound, almost like a supercharger. This noise was competely dependent on RPM, not transmission gear. I decided to pop the hood at my destination, with the truck still running, and it sounded just like a diesel at idle. No problem with missing, bucking, lack of acceleration, at least not from this issue. Truck did the exact same thing on the way home.

Lately it seems like my tranny can't decide what gear it wants to be in. It's sporadic, can affect downshifts when trying to pass, sometimes makes it feel like my transfer case is engaged, and can occasionally produce a wicked loud clunk from the rear end. (I have never experienced the dreaded rear end vibration on the highway.) And my mileage has been HIDEOUS lately. Looks like I'm in for another trip to the dealer. Anyone else experience either of these 2 things? Thanks.

 

I have noticed the tranny, "slip-clunk" In my 150. Seems like when I am coasting 30-50 mph, and get into the gas, "clunk"
MPG stillgood.

 

Sounds like the cam phasers need to be replaced.

 

Tony, just wondering if that suggestion comes from experience or a hunch. It seems a bit drastic to suggest that this early on. Kind of like suggesting a heart replacement for a case of heartburn.

jd, i notieced the tranny does it the worst between 20-30mph, around town, only when taking up the slack getting on the power again. The tranny also seems to shift into 2nd way too early, and then can't decide if it wants to downshift or not until extra throttle is given. Maybe the tranny learned my wussy, save-gas driving style lately and I should be a little harder on it.

 

Reforder, is the diesel sound only heard at idle? Does this sound disappear at about 1,000 rpms? Is it heard most notably on the passenger side of the engine from the wheelwell area? Usually heard after the engine warms up (oil thins out)? If you have these symptoms, it could be the cam phase sensors. Been there, done that. The whining, that sounds like something different altogether.

 

FS,
It's heard at idle regardless of engine temp, noticeable right away actually. Has been less the last 2 days. It's closer to the top of the engine, around the area of the stock air cleaner assembly/intake manifold. Just curious how a cam phase sensor could go bad this early, or if this is a TSB i should be aware of?

 

Most, if not all, of the posts I have read pertaining to the cam phase sensor problem have stated that the noise starts only after the engine has warmed up (doesn't take long on these trucks). Does it sound more like a "knock", or a "tick"? My cam phase sensor noise was definitely a knocking noise. Can you hear it inside of the truck with the doors closed? I could.*Your noise seems like it may be something different.

I began hearing the noise @ 1,000 miles. I had mine changed out @ approx. 12,000 miles. They are located at the front of the engine under the valve covers. From my understanding, a newly designed cam phase sensor was released in May 2005. If you would like the TSB, PM me.
I hope this helps.

 

This is a loud ticking or tapping noise, not a knock, from under the air cleaner. But it would be difficult to differentiate the sound from that area to the front of the valve covers. But it does do it directly upon startup. Did you notice any changes in vehicle performance with the bad sensors? It seems to run fine now, except for the tranny being funny between 1st and 2nd gears.

 

No, nothing noticeable.