deezel Posted February 17, 2004 Report Share Posted February 17, 2004 There have been numerous posts on the whining drivetrain noise at steady cruise between ~45mph and ~65mph. Mine has been there since very early on. I changed the fluid in the front diff and transfer case to Mobil1 synthetic - helped a little. I tried playing with front/rear tire pressures - helped a little. But none of these things has completely fixed the problem. I really really hope its not the bearings in the front axle... Anyway, I have another theory about the cause (but no obvious fix). I have done some logging of tranny parameters with EFILive - this started from Jason's question about the behaviour of his torque converter. I have noticed that in 3rd and 4th gear the torque converter clutch (TCC) goes into a "partial apply" mode where it is not fully locked or unlocked. GM calls this ECCC (something like Electronically Controlled Clutch Crap ? ). Anyway, I have noticed that the whining noise in the driveline seems to happen most when the TCC is in partial apply mode. Could the noise be caused by some interaction between the partial apply TCC and the AWD t-case? If anybody with logging software wants to chime in or try this, please do so. I logged TCCSLIP, TCCDC, GEAR, TIS, TOS and a few others. I made a gauge on my virtual dash that shows TCCDC and used the alarm settings to make it green when the TCCDC is <10% (unlocked) or >90% (locked) and yellow when the TCCDC is between 10 and 90%. That way I just have to look at the color of the gauge to know if its in partial apply mode... Link to comment Share on other sites More sharing options...
detjoe Posted February 17, 2004 Report Share Posted February 17, 2004 you are smart. I know who knows there stuff Link to comment Share on other sites More sharing options...
deezel Posted February 17, 2004 Author Report Share Posted February 17, 2004 Thanks for the compliment. I'm not an expert or anything... but I do like to understand how stuff works, and I'm somewhat of a perfectionist like a few others around here... (marc_w admits it too ). Link to comment Share on other sites More sharing options...
m396 #00-011 Posted February 17, 2004 Report Share Posted February 17, 2004 I'll get some logged data for you, if you want. BTW, I just changed my VE table for the 2nd time. The second set of data matched the first set in almost all areas within 1-2%. Link to comment Share on other sites More sharing options...
deezel Posted February 20, 2004 Author Report Share Posted February 20, 2004 Thanks for offering Jason. It would be great to somehow use a microphone to record the whining noise and correlate it to some log files. I haven't come up with an easy way to do this, so I'm just using my ears as the sound detector. Basically I just find a stretch of road where I can try to make the drivetrain whine as loud as possible, then observe the TCCDC gauge I mentioned before. Seems like a lot of the time the noise is there, the TCCDC is between 25% and 75%... On the VE changes.. are you entering 100% of the calculated value, or scaling it back some? How do you like part throttle now? Link to comment Share on other sites More sharing options...
m396 #00-011 Posted February 20, 2004 Report Share Posted February 20, 2004 Thanks for offering Jason. It would be great to somehow use a microphone to record the whining noise and correlate it to some log files. I haven't come up with an easy way to do this, so I'm just using my ears as the sound detector. Basically I just find a stretch of road where I can try to make the drivetrain whine as loud as possible, then observe the TCCDC gauge I mentioned before. Seems like a lot of the time the noise is there, the TCCDC is between 25% and 75%... On the VE changes.. are you entering 100% of the calculated value, or scaling it back some? How do you like part throttle now? I used 100%. I was confident in the values, and after reading your experiances, I decided to just go for it. I need to do some more logging though, I want to get some more of the higher rpm/ higher load cells. Link to comment Share on other sites More sharing options...
redsilveradoSS Posted February 22, 2004 Report Share Posted February 22, 2004 Sorry guys but i dont think i am in Kansas any more. This is all Greek to me! Good thing none of this stuff is left up to people like me. You guys work it out and let us know what to do to fix it. Link to comment Share on other sites More sharing options...
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