whats that squeak ??? HELP

[jdawg04 4.8]

So here the deal i have a 04 rcsb 4.8 with following mods

comp 212/218 w/supporting PRs and springs, JBA ti coated shorties, CAI, Loud exhuast, ASP Underdrive pully, LS1 fans w/harness, Built 60E, Eaton LSD, Tune by 12secSS, Baer Alumisport all 4 corners, Hotchkis swaybars front & rear, Nitrous Outlet truck plate, twin 15lb bottles, Trick Performance controller, 860 heaters and NX bottle openers

A few weeks ago a squeak started and i have had just about everything possible checked.

I first started in the engine bay with all belts and pullys and so forth when we noticed the sound wasnt even coming from the front but more from between the trans and oil pan.

So with that bit of info i took it down to my trans guy who aggreed that the noise seemed to be coming from the stall or possibly the trans pump so to make sure they disengaged the trans and stall from motor only to have the noise still be there.

Ive been told it may be crank bearing or cam bearing but i dont know since there no oil pressure problems any ideas suggestions please help its driving me insane.

Edit: and it only becomes audible after about 10-15 min of driving and only when at idle or slowing down if i give it gas the noise stops until i let of and the trucks hit about 30mph and also if i turn on the AC it seems to almost go away but slowly comes back. When the trucks cold no squeak i can even here the squeak turn off truck and back on and the noise will be gone but quickly returns.

[RedHeartbeat]

Could be a rocker arm.

[jdawg04 4.8]

but the squeak is cleary coming from the area between the trans and oilpan if i open the engine bay its so much quiter then if you get under the truck could it be the rockerarm

[skeet]

get a stethoscope or long solid rod, poke around on the block around where the noise is, listen for it and see if you can pin point it that way, sounds like ya got a gremlin running around lol j/k

[jdawg04 4.8]

get a stethoscope or long solid rod, poke around on the block around where the noise is, listen for it and see if you can pin point it that way, sounds like ya got a gremlin running around lol j/k

Did the metal rod to the ear thing thats how we traced it to the area of the far lower back of motor or front of trans but when we pulled the trans away from the motor the noise was still there.

Is there anything in the lower back of the motor that may due this but show no signs in the performance aspect of the truck i mean other then the squeak it runs strong for a 4.8.

and thank you for the reponses i have this posted on a few other forums and im not getting any respones. If i could afford it id find me a good LQ4/LQ9 but i just cant afford that.

[Madd Maxx]

You may have a cracked flexplate.

[jdawg04 4.8]

You may have a cracked flexplate.

Thought that to but when we pulled the trans away from the motor we checked the flexplate anmd did not see any signs of a crack.

[jdawg04 4.8]

any other ideas of what can cause a squeak that comes from the far lower back of the motor but not have to do with the trans.

[jdawg04 4.8]

well it seems to be the crank bearing so instead of tearing into her to fix ill just be shopping for a 6.0

[txarkitekt]

Well yeah--that is the only thing back there. Replacing a rear crank bearing on a 4.8L is pretty much a waste of time. Good thing: all the parts from your 4.8L will swap over to the LQ9.