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4T60: 5-speed automatic?


TeeJay3800

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Has anyone noticed that their 4T60 tranny seems to shift 5 times? I know that its a 4 speed automatic, but the RPMs drop 5 times and I hear/feel what I take to be five shifts taking place. I think I read somewhere that around 32-37 MPH some sort of clutch type thing engages to make a direct connection with the wheels or something. That may explain why it seems to shift 5 times. Does anyone know what I am talking about or can tell me what this is all about? :?:

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Well, four gears are mechanical and the fifth gear (aka Overdrive) is electronically activated. It's your the torque convertor locking up and giving you cruising RPM's to increase fuel econ.

 

- Erik

 

EDIT: cutlassdude96, darn you... you posted faster... :shock:

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Guest TurboSedan
Well, four gears are mechanical and the fifth gear (aka Overdrive) is electronically activated. It's your the torque convertor locking up and giving you cruising RPM's to increase fuel econ.

 

- Erik

 

not sure if i understand :?: there is no 5th gear. only 4, the 4th gear being Overdrive (.70:1). when you're in 4th you are in overdrive whether or not the torque converter is locked up or not. and yes RPM's drop when the TCC (torque converter clutch) electronically 'locks up' which makes it *seem* like a 5th gear, but it's really not. this usually happens at a steady cruise, and not when you are accelerating/decelerating or when you are on the brakes (these automatically unlock the converter). it's just a way of lowering RPM's and saving gas, and maybe lowering emmissions.

joshua

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...and yes RPM's drop when the TCC (torque converter clutch) electronically 'locks up' which makes it *seem* like a 5th gear, but it's really not...

 

I was trying to use laymen's terms in decribing what happens.

Basically, you nailed it Joshua. Thanks for the clarification!

 

- Erik

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Guest TurboSedan
...and yes RPM's drop when the TCC (torque converter clutch) electronically 'locks up' which makes it *seem* like a 5th gear, but it's really not...

 

I was trying to use laymen's terms in decribing what happens.

Basically, you nailed it Joshua. Thanks for the clarification!

 

- Erik

 

yeah that's what i was thinkin' :) you probably know WAY more about automatic transmissions than i do!

joshua

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