89 Suburban Shifting Hard

My 89 suburban seems to not want to shift up... it starts going just fine from a complete stop but when it is time to go to 2nd I can hear the enging rev... when I let off the gas and ease back into it that seems to make it shift... same with 3rd... I am thinking tranny problems but somebody mentioned that it could be a speed sensor or something? Please help...

Sorry, not a speed sensor. You transmission is not electronically controlled like later versions. The only thing the ECM does for the transmission on your vehicle is to control torque converter lockup, which has nothing to do with your symptoms.

I'd verify the fluid level, check the Throttle Valve cable (TV) adjustment, and test line pressure in all ranges. Use a 300 PSI gauge connected to the test port on the left side of the trans housing.

Thank you for your advise... but how do I check the TV adjustment?

http://www.tciauto.com/Products/Instructions/instructions/gm_tv_cable_adjust.htm

//2000CAYukon

Change the ATF, make sure it's the correct level. I had similar issue twice in my '88.

Sounds like a vacuum modulator on transmission to me. LOL, that is if this even has a vacuum modulator. If it does look on the tranny and you should see the modulator with a hose going to it. Pull the hose off and see if fluid is coming out of it. If fluid is coming out of it, it is bad and needs to be replaced. They can also go bad with no fluid coming out of them.