My dad just picked up an 02 Ram quad cab 4x4 with the 360 and 4 speed auto. It's a really beautiful truck with the sport package, 20" polished wheels, bed cover, leather, and the infinity sound system with SWAC. He loves the truck but it seems to have been neglected. I popped open the air box to check the filter and found the original mopar filter with 4 years and 78k miles of use. It was bad, in fact the worst I have ever seen. I cleaned out the air box and popped in the K&N I was using in my 04 and then checked all the fluids and such. Everything else looks good but its dirty and could use a good cleaning. He has been driving it for a couple of days now and the K&N made a world of difference. MPG went from 7 to 16 according to the thing on the roof. Yesterday he asked me to drive it and tell him if I think the rear end is making a whining noise. So I trade trucks with him and pull out into traffic. I had a nice open space so I punched it to get some speed to hear the whine. When the motor hit 4500 rpms at WOT, the ignition cut out and then back in and out and in and out till the truck almost stalled. I got control of it and limped it to the house. It drives normal as long as you stay under 4500. I reved it to 4500 in park and it does the same thing leading me to believe that the motor is the culprit. I had a dodge with the 318 in it and it would gladly go above 5000 without a problem. We took it and had the cap, rotor, wires, and plugs changed at his mechanic and that made the truck start, run, and drive better but it still cuts out at 4500.

Can someone suggest what is causing this?

How common is gear whine with the 3.92 limited slip rear?

Would new gear lube quiet it down?

Thanks.

Bob

 

From what you have said it sounds like your fuel pump might be shot or there's a clog in your fuel filter so try checking those, as for the rear end I know that in the maintainance manual for most rams they require you to flush the rear end fluid every 15,000 miles so if it was never done then that could have something to do with it......did you hear anything that sounded like shattering glass when you were driving it? If you did or do then your rear end is shot and the gears (all or a few) are broken/damaged

 

I'm with truckin151

Start by changing all of the fluids!!, filters, plugs and wires. Chances are that if the air filter was neglected, so was everything else. Also, download the FSM (factory service manual)---for free from this site (one of the vendors). You will need it. You may also want to consider running a couple of cans of SEA Foam, or Mobil1 w/techron injector cleaner through--just follow the directions. Start out Fresh!!! Its a lot of money up front, but you or I should say your Dad, will rest easier knowing its done. While you are doing all this, it might also be a good time to flush the radiator, and change the stat. Now, take it out and stomp on it for all its worth and see if that doesn't wake it up. Try to use synthetics where you can for the diffs and such, don't forget the additive for the LSD.

Now if it continues to drop out at 4500 rpm, you got a problem, come back here and ask.
This forum is a HUGE wealth of knowledge from the USA to Overseas.

Good Luck!!!!

 

Where is the fuel filter on these? Is it in the tank or inline? Everything else has been changed except the diff fluids. There's no chattering or sounds like the gears are damaged just a slight high pitched whine. He asked the mechanic about it when he picked it up and he drove it and said it sounds like a worn pinion bearing. If that is the case, I told him to buy another one and I'll switch the wheels, stereo, and interior and just sell this one.

If the fuel filter is a simple deal, we'll try that next and see what happens.

Thanks

Bob

 

fuel filter is not a easy deal it is integrated into the fuel pump in the tank. i believe you would have to drop the whole tank and replace the whole assembly. sorry to bring you the bad news [sm=boohoo.gif][sm=bomb.gif]

 

Yeah more than likely its gonna be in your tank which is a royal pain in the *** to get to. Also hows the transmission on it? I had a truck awhile back that made this awfull whining noise when you got on it and it was coming from the tranny. Also if you haven't already you might wanna crawl uder it and inspect the entire drive train from the back of the motor to the diff just to make sure everything looks ok and nothing is broken or damaged that could be contributing to it.

 

Could be hitting the rev limiter also due to a faulty park/neutral switch. If the computer thinks your NOT in drive then rev limit is low.
Quick check of PNS
Do the backup lights work?

 

I will check that monday morning when I get out of work. Where is that switch should I need to replace it?