I was hooking up a pop-up camper yesterday to head home and when i put the truck in park and hopped out i noticed a low growling sound similar to an exhaust brake (its the closest sound i can think of. its only happened twice so im not 100% exact on it yet). this went on for about 30 seconds to a minute then stopped. truck temps where fine as i had just started it and continued to run about mid 190's while towing on the way home. then about 5 minutes into my ride to work today it happened again i was going about 35-40mph. didn't last as long this time 10-15 seconds. prior to this i noticed my fan kicked on a lot which is weird since it was just winter and has not exceeded 70 deg here yet. the last time that happened was friday. the only other odd thing is every once in a while its hard to shift into gear. Any ideas or things to check would help thanks.

 

Wondering if your AC compressor is going out. Perhaps a bearing? When it kicks on you hear the nasty bearing eating itself. When it shuts off it goes away.

Just a shot in the dark taking into consideration the duration of the noise. My truck has an intermittent huff when idling. I thought it was an injector. When I shut the AC off, it didn't huff anymore. The timing this occurs is similar to what you describe.

 

this has been bugging me all day and actually the compressor crossed my mind. I will check those out tonight. thanks

 

My 05 will make a slight noise (1 second) when the AC kicks on and off. Perhaps yours is starting to fail and harder to turn and you are hearing the engine labor some while it picks itself up to keep turning the compressor.




I would pull the belt and check all thing that turn. You may have something turning tight and the AC compressor is fine but adding to the load.




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