2000 Chevy Suburban Transmission

[NikoTes]

Hello, First post here.

2000 Chevy Suburban 1500 4x4 (Automatic), 270k miles

I'm having an issue with my transmission switching gears. First and second are good but it never switches to 3rd and my RPM's go real high. I switched from D to 1, 2 and 3. 1 and 2 are good. I can drive in 3 but RPM's eventually go high.

D - 1 and 2 are good. 2 never switches to 3 and RPM's go high
3 - Drives in 3 but RPM's eventually go high
2 - Drives in 2
1 - Drives in 1

I thought maybe one of the solenoids are going but I'm not sure. Does anyone have any experience with this?

Thanks!

 

[zora]

It could either be a shift solenoid or something more internal. A diagnostic tool and procedure have to be run to determine the cause.

 

[Chuzz]

Have you ever changed the fluid and filter? You probably need to take it somewhere and have the CVI's checked and see what they show, but if it were mine, I'd just start with the fluid and filter change.

 

[Sierra Classic]

Sounds like a vaccum modulator, if they still use them on modern auto trans.