Is the 4 Speed A/S realy a six speed?

[Ian-PT-GT]

I have been noticed latetly that my GT will go into overdrive in third and in fourth gear.

if i am in fourth at a constant speed I can feel when the Lockup in the converter engages lowering the RPM at that point I move the stick to A/S mode, the screen shows "4". I start accelerating slowly, I feel like the car downshifted but it still in fourth gear.

I downshift to third, The screen displays "3" and the car goes higher in RPMs meaning it downshifted.

This means that the car went from Overdrive to Fourth to third...

Three imaginary gear changes???

This also hapens at slower speeds and the engine is in third...

Overdrive, third, downshift, seccond...

Has anybody noticed this latetly in the A/S???

Ian

[MEXICANPT]

All automatic transmissions do that, it's a four speed.

[MichaelDay]

As MexicanPT stated, that is common for all four-speed automatics with lock-up torque converters. When the torque converter locks and unlocks it almost feels as if there was a gear change as the rpms will rise as the torque converter unlocks even though you are still in the same gear. The torque converter performs the same function as slipping the clutch on a manual transmission to get the vehicle moving. Until the torque converter locks up, it is like constantly riding the clutch. Once the torque converter locks up you are then using the exact gear ratio that is stated in the literature, until then you are at an effectively between gear ratios.

[TripleJackInGA]

quote:Originally posted by MichaelDay

As MexicanPT stated, that is common for all four-speed automatics with lock-up torque converters. When the torque converter locks and unlocks it almost feels as if there was a gear change as the rpms will rise as the torque converter unlocks even though you are still in the same gear.

And if you wanna make sure your Torque Convertor is locking and unlocking like it should, go down the road at say a steady 55MPH in top gear (4TH) for a while. While watching the RPMs, just slightly depress the brake. You should see the RPMs go up just slightly.This is the Torque Convertor unlocking, and if you let off the brake again and cruise at a steady rate, you will see it drop slightly again as it locks back up.

[Ian-PT-GT]

I know that this is the way it suposed to work.

What I have never seen is this effect in third gear also...

I Had a TH700R4 trany in an IROC, it locked also, but it was only in fourth gear, not in third...

Ian

[TripleJackInGA]

quote:Originally posted by Ian-PT-GT

I know that this is the way it suposed to work.

What I have never seen is this effect in third gear also...

Used your cruise-control much yet? The first time I was on a long trip and used it, I noticed that when I would go down a steep hill, that if the car would go too much over what I had set it at, it would automatically unlock the Torque Convertor to try and slow the car down.

First time I had seen a car do that, and it kinda freaked me out.

[FlyingLow]

Ian-PT-GT,

Your Autostick transmission while in A/S mode will indeed lock the torque converter in either 3rd or 4th. 3rd gear lockup will occur around 30 mph (only in A/S mode) and 4th around 43 mph(in either A/S or full auto mode under light throttle). Also, while in A/S mode your trans. will not downshift under full throttle unless you are going very slow for the selected gear (i.e. low rpm). This is usefull if you don't like the rpm suddenly jumping way up when you don't need it to. I like that because it takes advantage of the tremendous torque our engines have at relatively low rpm.

Have Fun...


Flying Low

[TripleJackInGA]

quote:Originally posted by FlyingLow

Also, while in A/S mode your trans. will not downshift under full throttle unless you are going very slow for the selected gear (i.e. low rpm). Flying Low

Well, I dunno about that. I can start from a dead-stop in mine in 2, 3 and I *think* 4.

[Ian-PT-GT]

I guess it is the way it should work.[:I]

It feels like the TCM is always working overtime playing with all those shifts and locks....[]

Has any of you felt the car a little rough when shifting at slow speed??

I can feel it kicking forward when it shifts... like an old chevy or ford..

I like feeling that kick.. It makes me feel like there is a lot of power under the hood, but I just want to make sure that this is the way it should work...

Ian

[SteelBlueGT]

Mine shifts silky smooth only once did it feel like it hesitated and had a problem shifting as it felt like it was slipping or hunting for the correct gear!