Transmission stopped shifting into second and fourth gears

DON CORKE

MEMBER
2007 CHEVROLET AVALANCHE
5.3L
V8
4WD
AUTOMATIC
78,500 MILES

Transmission stays in first gear to over 4,000 RPMs let off gas shifts into third skips second and won’t go into overdrive. No codes thrown. Transmission temperature was running at 145 degrees at 60 MPH and engine at 2,900 RPMs on freeway to get home 60+ miles oil doesn’t smell burnt but looks a little dark oil and filter changed 5,000 miles ago.

Sunday, May 2nd, 2021 AT 8:44 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,052 POSTS

Hi,

This could be a few different things. First, there could be an issue with the transmission control module, an issue with line pressure, and so on. With that, we need to scan the can-bus system. CAN stands for controller area network. Basically, all the computers/modules are tied together via a few wires. If you used a standard type scan tool, it likely can not read all the codes.

Here is a video showing how it is done:

https://youtu.be/InIlnsjOVFA

If you haven't had this done, this is where I suggest starting. If you have already done this, let me know.

Take care,

Joe

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Wednesday, May 5th, 2021 AT 8:36 PM