So I tested for the sound over the past week and weekend. 1st through 3rd are the most obvious with 4th being next in line. 5th and 6th barily has it but it is there if I am under 1500rpm (which never really happens in itself).

My girlfriend noticed the sound right away and I never mentioned it. The car never once had this sound with the old transmission so something is either related to this transmission or from the install.

I remember when I first had the car I would hear the exhaust note, that it sounded amazing with it's tone. Now I can not hear it at all over this transmission sound. I am not sure if it is the transmission itself or if there are bent/loose heatshields from the trans swap.

I guess I will be calling the dealer sometime in the week and see what they say, it seems The car has been with the dealer more than it has been with me for this type of issues

 

I posted an update to my results here:
https://g35driver.com/forums/4051386-post97.html

 

everything is good now eh? good for you. You still have the warranty? and it covers the transmission? Thanks for letting us know about the result.

 

yup, still have bumper to bumper, so that ofcourse covers the trans. even without the bumper to bumper this would/should qualify under drivetrain warranty. Considering I didn't have the last trans in for much over a month if even, it should of been covered regardless.

I only had the car back since Monday but so far is feel exponentially better than even the last trans did at first.

 

The dieseling sound is completely normal and all cars do it to some extent when you put the car under too much load at low RPM. It happens because the timing is too far advanced for the the load at the time. You car has gears for a reason. If you put it in 5th at 1000 RPM and jump on the gas, the car will not perform well at all. It's not designed to perform well under those conditions - you are supposed to gear down. If you do it in 1st - no problem (and no diesel sound) because the engine is tuned for these conditions.

 

That however wasn't my problem. I had the sound in first and second and low rpm. My 2nd replacement trans fixed the problem and I no longer have the diesel noise. I agree if you lug the engine in high gear and low rpm you will hear all types of noises, which some people may be misinterpreting as something wrong. However some may have a similar issue to mine as it was extremely loud and happened in gears it should not have happened in.

Considering the replacement trans fixed the issue, it is safe to say that the service techs (and myself) were right and there was some internal failure of the transmission. They said it may have been some internal bearing (but who knows for sure).

What I do know, is when I first had the trans, that ended up having problems with noise, the shifts were very notchy and rather stiff. I figured at first that it was simply due to it being a fresh trans and needed to be broken in and loosened up. My new transmission however, felt perfect with the shifts from the beginning and does not have any issues as of yet. This has lead me to beleive my original replacement trans had issue from the very beginning.