3rd gear question...(newby)

[03gt2nv]

hey all, i will try to make this quick, i got a mint 03 gt with 25k on it i just picked up and it seems like when its cold it shifts a total of 5 times with little loss of rpm's between 2-3 shift. when its warm under normal throttle i only count it shifting a total of 4 times with a big rpm loss between 2-3, but under very light throttle conditions i can count 5 shifts even when warm. i havent tried wot yet, tranny feels good...no slipping of clunking, i know some of what im feeling is torque converter lock up, i had a brand new 04 gt a few years ago and it did the same thing. is this normal, does gm do this for economy reasons or do i need a pcm update or is it something more serious ?

[03gt2nv]

so, everyone can count 5 changes in their transmissions while driving at all times...?

[sunrunner_pei]

Please wait 24 hours before bumping threads.

You have a 4-speed transmission with a lockup torque converter. That equals 3 shifts (1-2, 2-3, 3-4), plus lockup. Are you sure you're counting right?

[rixGAphx]

The TC can lock-up in any gear, though it doesn't always do so in lower gears.
So you easily CAN feel 5, or even 6, distinct 'shifts'.

Old-fashioned pre-lockup converters were a 3-way compromise between adequate 'slippage' for smoothness, adequate 'tightness' for better fuel consumption, and adequate 'torque conversion' for performance.
When TC lock-up was first introduced in the late '70's, it was merely a feature slapped onto old fashioned TC's for decreased fuel consumption.

Modern TC's are now very gas-INefficient, but they produce much better 'torque conversion'.
The TC lock-up feature takes care of the former gas-saving compromise.
So the tranny is adjusted to stay in gear longer when operated for strong acceleration, but at the top of each gear's range the tranny *may* decide to lock-up the TC just for shits-n-giggles.
Then there's an actual upshift to the next gear, and the TC unlocks.

If you accelerate at WOT, you'll only encounter the TC lockup in 4th gear, when you eventually back-off the throttle.

If you hold the tranny in 3rd while driving on a twisty mountain road, you can feel the TC lock and unlock as the demand for torque varies (and you can see it, as a 150-200 rpm change on the tach).
Under this 'amateur-racer' scenario, IMO it would be desirable to have a TCC shut-off to prevent the gear hunting.

Hope this helps,
-Rick

[03gt2nv]

interesting, it just seems like sometime there is a big gap between the 2-3 and sometime there is a smaller gap, i guess this theroy would make sense to me. i bought this car because im sick of buying new cars and having them depricieate and loose hoards of money on leases, so i gotta make this one last and i didnt want the tranny self destructing itself like some gm fwd trannys have done in the past. from the sounds of it all is well but anyones comments would be appricieated.

[sunrunner_pei]

I don't think there is anything wrong with your transmission. :)