Hey yhere guys. I hope I'm in the right place to ask this question. I have a 98 Dodge Ram 1500, V6, 3.9 litre engine. The truck runs like a champ and still gets great gas mileage. The problem I am having right now, is that when I drive the truck, I get a tapping sound as though the lifters or the valves might be tapping. This ONLY happens whenever the truck is moving and it seems to ONLY happen when the speedometer is going up. From the stop or netural position, you can rev up the engine and hear no tapping whatsoever. If I'm driving the truck and let's say get up to 70 mph, and maintain the speed at 70 mph, the truck runs very quiet, but once I start to press on the gas, I hear the tapping sound. And it doesn't matter at what speed I maintain,( 20 mph, 40 mph, 35 mph), it's only when I press on the gas pedal does the tapping noises come back. Had the engine looked at and was told by a very good mechanic that the engine is sound and that it's unlikely the tapping noises are coming from the engine. Could the tapping sounds come from anything having to do with anything having a connection with the speed controls?? ANY help would be GREATly appreciated in this matter. Thanks a lot in advance....

 

im having a similar issue,not sure if mine is tapping but definitly something. Happens at 35+ when giving it gas but as soon as i let off gas it goes away,give it gas,comes back..Im leaning towards exhaust manifold gasket leak...might be yours too.Lets see what others think.

 

Exhaust manifold leak, lifters, valve, or noisy injector. Are you sure its ciming from the motor and not the diff?

 

Dont think it would be the diff for him or me for the fact that the noise is noticeable with throttle. With mine i can be coasting at 70mph and dont hear it, if i give it throttle i hear it. If it was the diff for either of us wouldnt it be making the sound even coasting at higher speeds?

 

Nope. When you're on the gas the pinion puts pressure on the backs of the ring gear teeth, and when decelerating the ring gear puts pressure on the backs of the pinion gear teeth.

I'm not saying that anyone's got a screwed up diff, but it's common that they'll growl or grind only when accelerating, or, rarely, only when coasting.

 

That worries me now, I also have a clunking sound when i put it in reverse and when it shifts if im going slowly. Pretty sure one of my u joints are bad but maybe my diff is bad also....thats pricey.

 

In my experience, the most common of the ones mentioned and not mentioned is #1. fuel octane....get some good fuel injector cleaner + octane booster and mix it with your fuel......#2. overheating will cause this also, so make sure the engine is not running hot ( ck for bad radiator cap and ck radiator coolant level)
#3. timing...If your timing is off (to advanced) it will also make the lifters rattle.....#4. sticky lifter...Put some lucas (or similar) additive in the oil....I would look at those things first, take a couple Ibuprofen, and If that don't work! call the doctor back in the morning...LOL

 

If you know U joints may be bad, fix them first then see if ticking is gone....before you lose your driveshaft on the highway (like at least one member here did).

 

Hey guys..Thanks for all of the input to my tapping noises coming from my truck. Within the last few months, I have had the radiator and cap replaced (leaking), all ball joints replaced, all shocks replaced, thermostat replaced, had a compression check done, always replace my oil and filter at 3000 miles or every 3 months, always use Lucas oil treatments and Lucas gas treatment. Had to go to Atlanta yesterday after I posted here (5 hrs one way) and just got back here today (Fayetteville NC). Instead of driving my 2011 Ram, I opted to drive the 98 Ram down and back just to see what would happened. As I stated yesterday, the 98 gets great gas mileage, got to Altanta and back with no problems. So I think I'm gonna get me a beer, change the oil in the 98 and call it a day,lol...Thanks again all for your help. Have a great and blessed day.