I do not know of any techs up there at all. Sorry. Your observations on competency are not unique. Too many are resisting the new technology.


The shifting in that transmission can not do gear-to-gear like a step gear transmission. It has to step between gear-to-mode-to-gear. So on the way from fixed first to fourth, it makes the mode jump three times.


Have you towed something around 5000 pounds yet with it?


The performance is surprising.


So the least expensive thing to try if the buzzing is inside the front of the transmission is a new front pump housing.


But the whole transmission has to come out.

 

I have pulled a 6,000# camper with equalizing hitch. The '08 pulled fine for power, but the it wandered something terrible. The '12 is much more stable (Denali so magnaride) but doesn't pull as hard as the '08 did, and where the '08 would change gears/modes during long acceleration the '12 just holds rpm.

I find it interesting that the shifting feel from 2008 to 2012 is completely different. Foot to the floor in the 08 and it pulls somewhat hard through first ev mode, then big slow shift to 2nd ev mode and pulls hard after that. The new ones feel like a cvt, just sits at 5k rpm. Pull varies a bit as it shifts, but not much. The '12 is a dog off the line, and flares from pulling harder at 4k up to being really weak at redline between modes. Finally pulls hardest at 70 mph. The '12 takes 4-5 seconds to go full throttle after hitting the gas, and is a good 2 seconds slower to 60 than the '08; something is definitely not right.

Feels like maybe the clutches for the static gears are not grabbing as quickly as they should, but impossible to know without a scan tool. I'm hoping I can convince the tech that there is enough going on to justify a transmission instead of chasing solutions that won't do anything just to avoid a transmission.

I greatly appreciate you taking the time to respond; I've learned a lot of what I know about these trucks from your posts & would be in the dark without them. Thank you sir.

 

i am new to this site. I am having a increase in RPMs when in park and an associated whining noise. Started to see smoke coming from exhaust? Not sure but now it seems I don’t have proper electric trans operations possibly that the electric pump for transmission operation isn’t operating correctly. Any ideas would be appreciated

 

What year