84 Manual
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Burning Brakes
Joined: Dec 2016
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From: Topock AZ
84 Manual
Hi I'm looking at a 84 with manual transmission. Can someone tell me if those are good transmissions? I know they are called a 4+3. I don't know anything about these transmissions so I would appreciate any info you can give me. Thanks.
Gary
Gary
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From: near the thumb in the mitten
Borg Warner super T 10 4 speed with an electric Doug Nash overdrive unit made to it. O/D has separate switches. One to turn it on and a vacuum kick out. You want to make sure 4 speeds shifts and O/D engages with switch and will kick out at WOT. It will feel like a automatic transmission downshift, when you lift O/D should re-engage. Shifter is unique it mounts to body not to transmission.
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
This page tells you how the 4+3 works for each year. Note that the '84 version is different in when it shifts, and how it will downshift. The early 4+3 will have a switch on the dash while later versions will have a button on the shift handle. The 4-speed portion is strong and is made up from the Borg-Warner Super T-10. Corvette engineers used the add-on Doug Nash OD unit to satisfy the then-current CAFE gas mileage requirements. It took them until 1989 to start using the ZF 6-speed.
One important thing with the OD is to perform annual fluid and filter changes. Pretty easy to do; drop the pan and clean everything. Straighten the pan rails and use a good RTV sealant in place of a soft cork gasket. The filter is the same one that was used in Ford "FMX" auto trans found on the early '70's Cougars, Fairlanes, and some F-150 pickups. When you pull the old filter out, remove the rubber grommet and install on the new filter. The filters that come from the Corvette accessory catalogs will have a new grommet. The catalog filters will run $25 to $30 but the Ford version you get at parts stores will cost $10 to $12. Here's some p/n's: Carquest (Advanced) 85926, AC Delco TF-184, Fram FT1024, NAPA ATP14717. Use a good grade of DEXIII ATF (< 3 quarts) but not synthetic.
One important thing with the OD is to perform annual fluid and filter changes. Pretty easy to do; drop the pan and clean everything. Straighten the pan rails and use a good RTV sealant in place of a soft cork gasket. The filter is the same one that was used in Ford "FMX" auto trans found on the early '70's Cougars, Fairlanes, and some F-150 pickups. When you pull the old filter out, remove the rubber grommet and install on the new filter. The filters that come from the Corvette accessory catalogs will have a new grommet. The catalog filters will run $25 to $30 but the Ford version you get at parts stores will cost $10 to $12. Here's some p/n's: Carquest (Advanced) 85926, AC Delco TF-184, Fram FT1024, NAPA ATP14717. Use a good grade of DEXIII ATF (< 3 quarts) but not synthetic.
Advanced
Joined: Feb 2017
Posts: 86
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From: San Antonio, Fl Florida
Doug Nash tranny.
This page tells you how the 4+3 works for each year. Note that the '84 version is different in when it shifts, and how it will downshift. The early 4+3 will have a switch on the dash while later versions will have a button on the shift handle. The 4-speed portion is strong and is made up from the Borg-Warner Super T-10. Corvette engineers used the add-on Doug Nash OD unit to satisfy the then-current CAFE gas mileage requirements. It took them until 1989 to start using the ZF 6-speed.
One important thing with the OD is to perform annual fluid and filter changes. Pretty easy to do; drop the pan and clean everything. Straighten the pan rails and use a good RTV sealant in place of a soft cork gasket. The filter is the same one that was used in Ford "FMX" auto trans found on the early '70's Cougars, Fairlanes, and some F-150 pickups. When you pull the old filter out, remove the rubber grommet and install on the new filter. The filters that come from the Corvette accessory catalogs will have a new grommet. The catalog filters will run $25 to $30 but the Ford version you get at parts stores will cost $10 to $12. Here's some p/n's: Carquest (Advanced) 85926, AC Delco TF-184, Fram FT1024, NAPA ATP14717. Use a good grade of DEXIII ATF (< 3 quarts) but not synthetic.
One important thing with the OD is to perform annual fluid and filter changes. Pretty easy to do; drop the pan and clean everything. Straighten the pan rails and use a good RTV sealant in place of a soft cork gasket. The filter is the same one that was used in Ford "FMX" auto trans found on the early '70's Cougars, Fairlanes, and some F-150 pickups. When you pull the old filter out, remove the rubber grommet and install on the new filter. The filters that come from the Corvette accessory catalogs will have a new grommet. The catalog filters will run $25 to $30 but the Ford version you get at parts stores will cost $10 to $12. Here's some p/n's: Carquest (Advanced) 85926, AC Delco TF-184, Fram FT1024, NAPA ATP14717. Use a good grade of DEXIII ATF (< 3 quarts) but not synthetic.
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