Ok after $2500 replacing this thing im scared something might be wrong with my engine again. I have noise coming from the engine that i was told was the a/c compressor but after removing the belt its still there. Ive tried tracking it down with a stethoscope from uptop but nothing yet. I guess ill start with what i know is wrong with the car then try to explain the noise it's making. First ill start with my auto trans, when cold it shifts so-so. Bit after 2-4 mins when u take off from a stop it just goes upto 3-4k rpms an about 20 mph then u have to let off the gas to get it to shift if it doesn't sometimes u hve to feather the gas a little like revving up n letting off till it goes. The shift from 2nd to 3rd also slips but not nearly as bad. I know its shot. But heres where the tapping/ knocking comes in. It's barely noticeable when started up cold if at all. After about 2-4 mins around when the trans starts acting up when i take off i hear this ta ta ta ta noise from the engine. It speeds up with the rpms and slows with the rpms as i work it into shifting to second, then if i give some gas say 3k rpms u hear the ta ta ta ta noise but not as loud. Once it shifts into 3rd i don't think i hear it all wether taking it easy or accelerating to 60-65 quickly and cruising it seems to almost disappear until i alow down an trans down ahifts. Now when i come to a stop while in drive an everything warmed up i can hear it faintly sitting there. Ta....ta....ta then when taking off again ta..ta..ta..ta almost faster than the rpms. I have put trans in rev warmed up an backed up fat spinning wheels an don't believe i hear it then. Could this be in the trans? Instead of the engine? Cold start up i have 40-43 psi on factory oil guage once warmed up it sits at 22-23 psi an shoots past 40 when I accelerate. An warm at about 1500 rpms i have 33-35 psi pressure. Below are the details on the engine swap etc...

Started factory 1998 t/a ls1 engine that hydrolocked at 81,000 miles.
Replaced that engine with a 1999 z28 ls1 engine.
Mechanic said he used the 1999 z28 bottom end and heads but swapped the 1998 t/a intake manifold and fuel rails/ injectors an throttle body over to the 1999 z28 engine and then installed into my car. And thats where i am today.

Im hoping something rings a bell with you more experienced ls1 guys hear, or naybe some tips to narrow it down? Someone said I should of had to use the pcm from the 1999 Camaro for some reason, any truth to that? I believe they also used the 99 z28 exhaust manifolds aswell. I dont see anything in the oil after pulling the dipstick after driving a few miles an wiping it on a clean white piece of paper. Thanks for input you may have.

 

My first thought is torque converter

 

Or loose/ broken flex plate. Also check your fluid level for the shifting issues if they weren't there before

 

Yea it's been shifting like that for about 300 miles now, I may try changing the filter idk if it's worth it or not, i did take about 4-6 quartz out through the dipstick fill tube with a transfer pump an replaced with fresh fluid and a bottle of lucas oil treatment didn't seem to make much a difference. Guess I'll have to find a way to get it up in the air tomorrow to check the converter bolts and flex plate. Ill also post a video from when i start it an keep filming while i drive a few miles if that would be helpful. I do have a small roof to do tomorrow so it won't be until sometime afer say 2pm

 

Any ideas about the pcm i heard about? I was told because i used a 99 engine an my cars a 98 that I should of swapped those aswell

 

Only if you changed the wiring harness.

 

If he didn't swap your 98 oil pressure sender don't go by the factory gauge.

The 98s had a much more accurate 2 wire sender, where as the 99+ cars got a 1 wire sender with a dummy gauge on the dash.

 

If your going to have the car up in the air to check the converter bolts you might want to try unbolting the converter and push the converter forward a little and then start the car with it unhooked. This will let you eliminate the trans as the cause of the noise.