overdrive ? on the 4L60E

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May 26, 2010 | 04:47 PM

badmfkr

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From: Atlanta, GA Ft. Walton Beach, FL

overdrive ? on the 4L60E

I allways thought that when the 4L60E was in four gear that it was in overdrive is this true or false?

car is a 99WS6

Thanks

May 26, 2010 | 04:53 PM

MIKEY'S 2002 TA

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over-drive

you have over-drive then torque converter lock-up which almost has the feeling of going into a fifth gear. the lockup can be set to occur at what mph you want it to

May 26, 2010 | 05:03 PM

Mike@Century

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4th gear is "overdrive", .70 ratio. You also have TCC, which can engage in 4th & 3rd gear.

May 26, 2010 | 05:29 PM

badmfkr

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over even in third gear?

Quote:

Originally Posted by Mike@Century

4th gear is "overdrive", .70 ratio. You also have TCC, which can engage in 4th & 3rd gear.

what is TCC.

if you're cruiseing real slow say 35MPH will it shift to 4th or stay in 3rd overdrive?

Quote:

Originally Posted by MIKEY'S 2002 TA

you have over-drive then torque converter lock-up which almost has the feeling of going into a fifth gear. the lockup can be set to occur at what mph you want it to

can you crusie around without going into overdrive ? say like if it was left in #3 position instead of drive?

May 26, 2010 | 08:45 PM

Azrael

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Quote:

Originally Posted by badmfkr

what is TCC.

if you're cruiseing real slow say 35MPH will it shift to 4th or stay in 3rd overdrive?

can you crusie around without going into overdrive ? say like if it was left in #3 position instead of drive?

Overdrive is 4th gear, or more correctly any gear that is lower than a 1:1 ratio in the transmission; in the 4L60E that is 4th. Most manufacturers stock transmission programing have the car shift into overdrive while cruising, even at low speed, for fuel economy. This really is just for mileage, and you should be using "Drive" to tool around town to keep the transmission from shifting. This locks out overdrive, and will use the first 3 gears of the transmission. IMHO the problem with the overdrive is the amount of shifts it causes the transmission to make, shifting is friction which creates heat, which kills the transmission. Most transmissions are rated for shift life, along with other factors like torque application.

The 4L60E is a torque converter lock-up transmission, that will lock the torque converter; also for better fuel economy. That is sometimes misinterpreted as a "shift" when it is actually still in the same gear you just see the rpms drop and the car jolt when the clutch locks up (similar in a way to the clutch on a manual car).

Transmission tuning can change these variables, as well as transmission modification, or adding a higher stall torque converter.

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