When it shifts from 2 to 3 the transmission slips completely

2007-chevy-colorado-z71

My truck moves fine in 1-2, and R. When the trans shifts from 2 to 3 the transmission slips completely. The truck slows and engine RPM goes up. Manually shifting to 1-2 and the truck moves again. I’ve replaced the shift solenoids, fluid, and filter. Same results. The problem happened on the road without warning. The trans no longer drives the truck in 3-D. All other positions of the transmission operate normally. Where should I concentrate my search for the problem? It is a 2007 Chevy Colorado 4×4 Z71 package.


I’ll be the first to tell you that I am not a transmission expert. But I will do my best to give you some direction in the matter.

When it comes to transmission trouble shooting I like to start with the color and level of the transmission fluid. If the color is dark and smells burn you may be in for more than you bargained for. If the transmission is causing you an issue and the level is full but still burnt looking you are looking at needing a rebuild. The dark color comes from the worn clutches inside the transmission. The clutch material is similar to that of brake pads and when they wear they leave dust similar to brake dust collecting on your wheels. This causes the fluid to become dark in appearance.

If the fluid looked pretty and clean when you changed it, it may be an electrical issue. At this point you will want to extract any existing Transmission codes. These are different than check engine light codes. You may need a transmission shop to pull the codes you need to point in the right direction. However sometimes the the check engine light will hold codes too. A faulty VSS can create havoc and cause severe shifting issues. This is usually accompanied with a C0055 code.