Quote:
Originally Posted by Reino
how exactly do you shift it?
1-2-OD2-3-OD3-4-OD4,
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Actually 1 ,2 ,3 , 2-Od ,4 , 3 -O/d , 4-O/d
Ratios
1st . 2.88
2nd. 1.91
3rd . 1.33
2-O/d. 1.18
4th. 1.00
3-O/d. 0.83
4-O/d. 0.62
but as 2nd O/d is close to 3rd and 3rd O/d close to 4th there is little point.
Most only engage O/d in 4th when on the open road to get the fuel economy from the reduced revs
You need to be aware,by default ,O/d is always on ,so once the engine reaches the correct temp the computer will automatically engage the O/d ;so from a stop you will get 1st ,then straight into O/d in 2nd , 3rd and 4th gears.
"The reasoning behind the 4+3 is similar to the skip-shift on the 6-speed manuals - to meet EPA
mileage requirements in both the city and highway cycles by getting to top gear as quickly as possible.
The EPA has specific rules that do not allow short-shifting or skip shifting by the driver, so in both cases the car
is set up to skip-shift on its own.
The early C-4 solution was to put an overdrive unit on the T-10 4-speed and have the car automatically
go into overdrive when you shift to second."
Pushing the button before driving off gives you full manual control of the O/d ;
not touching the button means the computer will engage the O/d as programmed
But I found 3rd O/d handy in traffic because with the auto kickdown function , if you hit the gas hard enough it will drop into 3rd direct for passing and then shift back up into O/d when you let off the gas ;similar to a 4-3 downshift without moving the gear lever.
Different years have different functions ; read this to compare operation
http://www.5speeds.com/43table.htm
If car is new to you and the service history unknown , drop the pan on the O/d , change the filter and
replace the fluid (Dextron III )
You won't find the O/d filter at your local dealership but the filter from a FMX trans is the same
http://forums.corvetteforum.com/1571645223-post6.html
One of the reasons the 4+3 got a bad name was partly due to the O/d not being serviced at the factory
specified 12K intervals ; some owners treated it like a reg auto trans with bad results
