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So a few days ago I guess this started and I'm really at a loss. Its getting a little worse now and I was going to take the truck on a little day trip tomorrow and now I'm not so sure. It sounds like a bearing tick when the bearing goes bad, but here are a few weird facts about the noise. It only occurs in forward gears under medium / hard acceleration, its there under load acceleration but very quiet.

Once you are no longer accelerating the noise goes away. It is directly linked to the speed of the vehicle, engine rpm, or transmission more specifically because if I am going very slow it is a methodical tick, and the last tick you hear is almost like a ttttiiiiiiccccckkkkk because of the speed. I mean, it really sounds like a freaking baseball card in the spokes of your bike. I do know that when it shifts gears the ticking stops and starts again to almost match the speed of the engine, not so much the speed of the vehicle.

I'm trying to diagnose the thing, and I looked under the truck today while my wife was accelerating it very slowly and I just didn't see anything. All the body bushings are snug. Tranny mount, catylitic converter have no slop in them. Its not related to the A/C being on in the front or the back. The truck DOES have an autoride suspension in the back, but the tick sounds like it is coming from the mid point in the drive shaft, so perhaps where it connects to the transmission. I was thinking maybe that it needed grease, but the more I ponder it, the more I realize that it is linked to the speed of the engine and the strain, not the speed of the vehicle.

I really think that this is drive train related between the tranny and the engine and I just hope the hell its not the torque converter... I do have 22" wheels, and they may be putting a load on the vehicle. However, it sounds ridiculous that this thing can tow 9000 pounds, has an auto ride suspension, and has been defeated by wheels and tires that are only about an inch bigger in diameter than the stock set up. I have a Vortec 5.3l, and the year is a 2002. Please someone, give me something to think about!!! 'Carl
 

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you're correct on the wheel issue (or lack of issue) The rest of the problem, I think is over my head. Be sure on it being engine speed and not forward speed. Do you think you can reproduce it on a dyno? If one in you area. Another mech. friend in the area?
 

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2wd or 4wd? if 2wd does it have a steadybearing on the driveshaft? Could be a u-joint
 

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Check those U-joints again. Bigger wheels (unsprung weight) will eat u-joints as fast as lifting a truck.
While your new wheels are only an inch bigger whats the weight gain per wheel/tire, unsprung weight on a vehicle (any weight below the springs, i.e axles & tires) has a large affect on performance.
 

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Under acceleration when it shifts does the frequency of the tick change, if so it is engine relates. If it stays constant it is in the drive train. If it is engine related it could be something as simple as a lifter which may clear up with a pint of Marvel Mystery Oil.

Phil
 

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I had the same noise from my '95 sub. it was a small exhaust leak where the exhaust manifold met the head and only ticked during accelleration. powerbrake your truck and see if still ticks. if it does it could be an exhaust leak and you can poosibly rule out drivetrain.
just my .02
 

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From your description, it does seem related to engine speed rather than vehicle speed.
Exhaust leak is one possibility.
My first thought was spark leak. Look Under the hood in the dark and see if you can see any arcing around the spark plug wires. Spark leak tends to be worse under load when the ignition system is working harder.
Lifter noise is another possibility. What's the oil pressure look like?
 

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Discussion Starter #8
So anyway, I'm sorry I didn't check back and let everyone know what happened. It started getting pretty bad and would effect the acceleration of the vehicle with any sort of a load. (meaning, not going down hill) Once again, I crawled under the truck and started wiggling anything and everything. Long story short, one of the bearing cups on the ear u-joint must have shattered. It was causing a slight vibration in the drivetrain and developed over time. When I pulled it out it was shaped like a bullet signifying it was the original problem, and since it wasn't originally bad enough for me to feel, I was finally able to have something that was profound enough to actually diagnose. I was pretty sure it wasn't the engine since it was only related to the vehicle speed, and I'm glad that I ended up with a whopping $11 part from the auto parts store instead of having to rebuild the tranny...
 
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