hard shifting

[Domestics_Only]

My 99 Chev has been shifting really hard latly, i know that the torque converter is supposed to absorb the initial shock of the shift, so does this mean the TC is starting to go? or is it something less expensive?

[slreno1217]

try cleaning the mass air flow with a electronics cleaner ... if it is dirty and thinks the vehicle is under load it will make vehicle shift harder might be an easy and cheap fix.

[merc81]

I doubt the air flow sensor is going to help, but its easy enough to try. Most likely is that you have the solonoid problem the 4T65-e tranny is famous for. My 99 silo started hard shifting around 90k miles. I added a tranny cooler that helped quite a bit at first, but the problem just kept getting worse.
These forums are full of info on the hard shift problem--do a search for comments on how to fix it. I repaired mine by changing two solenoids, the TCC & the PCS. Its not hard, and not expensive--just takes time.
The 4T65-e tranny had two common failures, both solenoid problems. The TCC valve would wear and become stuck causing the tranny to lock the torque converter. This feels like shifting with no clutch. Sometimes when it was really hot, the car would shudder and try to stall when coming to a complete stop. Starting from a dead stop would also cause bucking, shaking, all the effects of trying to shift a manual transmission with no clutch. Often, driving along level roads the car started to bounce forward, or shudder because it needed to shift into or out of overdrive. Sometimes when trying to accelerate hard, or even go up hill, it couldn't downshift and the car would loose speed.
The other solenoid that fails is the one that controls line pressure, the PCS. Both are pretty easy to change once you open the side panel on the transmission. They are about $25-$30 each so I changed 'em both.
Since replacing those solenoid/valves, my silo has been silky smooth on shifts.