I have a new 2008 ranger (4k miles) with 3.0 V6. When driving at around 1500 rpm with A/C on it has a rough or grinding feel to it. Without the A/C it's fine.
Dealer changed the serpintine belt which did nothing to fix it.
My question: has anyone heard of this before. I suspected a faulty compressor but before I battle with the dealer I want to be sure it is not something normal due to gear shifting with A/C on or some other normal action.
Any ideas?

 

I had a similar problem in my 4.0. It would even stall out. I bought a new fuel filter and plugs. I changed out the filter and everything's good. I'll wait for the plugs.

Try that, worked for me.

 

Do you have a stick?

 

No, it's an automatic transmission.
It seems to be more apparant after the truck is driven for a while with the A/C running. I feel it when the engine gears down to around 1500 rpm and below and when it starts moving from a stop. It seems to have full power.

 

Bad gas maybe?

Or has it always done this?

 

When you say "gears down" Does this mean you are slowing down and the truck downshifts? Is it at this time it makes this odd noise?

 

Thanks for all the replys.

"Bad gas maybe?"

It has done it through many tanks of gas from different stations.

"When you say "gears down" Does this mean you are slowing down and the truck downshifts? Is it at this time it makes this odd noise?"

When it slows down to a speed that puts it at around 1500 RPM, and from a stop up to about 1500 RPM you can feel the roughness or grind (though no metallic sound). You can sense a little vibration in the steering wheel. It almost feels like the trans is working harder at and below 1500 RPM with the A/C on but do not feel it hard shifting. Also, it seems to not be as bad even with the A/C on until it is driven for a few miles. I've had Rangers with 3.0's for about 15 years and never felt this. That is why I was wondering if it was normal for the '08' 3.0 or transmission, did they change anything from previous years engines?

 

I think you need to get a mechanic in the truck with you on a test drive. It doesn't sound right to me.


Maybe you have a bad torque converter. Im not really sure.

 

Thanks for the input.
I had the dealer's shop forman drive in it with me the first time - he had me leave it, then they changed the belt. Now when I call them they say they could'nt find anything wrong. I will go to test drive another one tomorrow and see if it does the same thing.
Problem is, every time you leave your vehicle you must find other transportation. The idea behind buying a new truck was to not have to keep it in the shop.