I’ve got an 02’ Silverado that has 300k on it. It ran fine but I wanted more power. I had a shop put in a new engine & Procharger. Since then I’ve noticed a slight vibration that has continued to worsen, it’s been probably 4,000 miles since new engine. Feels like it’s in the front somewhere as I can feel it through the floorboard and through the steering wheel. Also since then, new tranny, torque converter, rear end/axles, front differential/axles, brakes, transfer case, front and rear drive shaft with new ujoints, new steering shaft. The vibration has been persistent and gotten worse. It’s not there in park when idling, but is there when put in drive or reverse. It’s there off and on when driving at slower speeds in town and is there at higher speeds especially when the converter locks up. Seems to still be there slightly when put in neutral at highway speeds but doesn’t seem as bad. It completely disappears under acceleration during a 0-60 or 1/8th mile pull, smooth as butter and the data logs show no problems with the engine. My best hunch is motor mounts as the shop that swapped my engine didn’t replace them. The engine doesn’t jump around and appears pretty solid in the bay but I’m wondering if one of the mounts rubber has worn out inside and now it’s metal on metal. When braking after a pull, the vibration is very noticeable. All indications online suggest that a motor mount would be the culprit if accelerating but not braking so that is confusing but maybe the engine lifts off the worn mounts when accelerating and then settles back down on it when braking. Super frustrated as it’s been a year and I’ve already spent a lot of money. Any suggestions would be greatly appreciated.

 

Sounds like doing motor mounts is a requirement at this point. If the vibration still persists after that, then we are looking at suspension related items. While you are under there doing mounts, look things over. It is a 4x4? maybe something is rubbing or resting on the front diff and transmitting a lot road noise

 

Yes I’m hoping to change out the mounts this weekend and will give it another look over. I’ve had it on the rack with the engine on, put it in gear and let the tires spin but couldn’t reproduce the noise. Yes 4wd, new transfer case and shaft so that seems pretty good. I need to check headers and X pipes to see if anything is off.

 

Sounds like you're on the right track

Are the diff bushings good? Are the bolts holding the diff and mounts on tight? Check the passenger side for the Y bracket bolts and nuts and there is a long bolt on the driver side that could be suspect

Check CV play. Check wheel bearings. Inners/outers wear really fast on the 1/2T trucks, especially with non stock angles or larger tires

 

ok will do and thanks for the advice

 

While replacing the motor mounts I had to take off the headers and the spark plugs which revealed one plug was burned out and another plug had oil on the threads. Replaced all the plugs and the two motor mounts but the problem is still there. Now I’m wondering if the vibration is coming from the engine and whatever caused the plug to get oil on it. I did a pull today in first gear, went up to 20lbs of boost and felt very smooth but didn’t feel that snappy. The vibration is really bad right after a pull, and if I stop in the middle of the street to turnaround and head back the other way it definitely is missing and wants to die. Thinking back on it this has been going on for quite sometime. I have the ATI balancer for the Procharger and the crank snout does not appear to wobble. It doesn’t seem catastrophic but something is definitely off. With how much it’s going to potentially cost somebody to dig around and see what’s going on, I am about ready to get the bigger 6.2l block, turn the boost down to 12 or so and make just as much power as the 5.3l on 22psi.

 

22lbs on a gen3 5.3?!

That thing built or you just feeling lucky?

 

I had a vibration once, after I popped 3 ring lands at 14.2 psi and nearly 20 degrees of timing.

 

Everything built but the crank