Corvette servo?

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08HoeCD

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Other than its low cost, does the Corvette servo mod offer advantages as opposed to a custom tune?
 

rockola1971

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All the corvette servo does is replace the factory 2-4 band servo and give around 50% more holding power for 2nd and 4th gear. It goes in your transmission on the passenger side. The round circle on the side is the cover.
When you launch a vehicle you are in first gear and then it shifts hard to 2nd. To achieve 2nd gear a hydraulic circuit in the tranny pushes servo against one side of the 2-4 band (other end is anchored) against the input housing to hold it stationary. The band slips and it eventually burns up with too many hard launches.
Corvette servo doesnt make you go faster. Just keeps the tranny from slipping as easily in 2nd and 4th gear.
 

Tonyrodz

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All the corvette servo does is replace the factory 2-4 band servo and give around 50% more holding power for 2nd and 4th gear. It goes in your transmission on the passenger side. The round circle on the side is the cover.
When you launch a vehicle you are in first gear and then it shifts hard to 2nd. To achieve 2nd gear a hydraulic circuit in the tranny pushes servo against one side of the 2-4 band (other end is anchored) against the input housing to hold it stationary. The band slips and it eventually burns up with too many hard launches.
Corvette servo doesnt make you go faster. Just keeps the tranny from slipping as easily in 2nd and 4th gear.
So do you think it's worth it? Kind of confused on what's the cause of the band burning up.
 

rockola1971

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The FACTORY band will burn up prematurely if you launch your vehicle hard alot. Neutral drops contribute immensely to this. Installing the corvette servo immensely improves 2nd holding power(the band tensioned onto the input drum). A corvette servo cant hurt. Its really good for towing (4th/OD). I wouldnt build a tranny without the corvette servo upgrade. Its cheap extra insurance.

Vid on replacing the servo.

Vid on complete rebuild. Disconnect anchor of band at 21:30 and removal of input drum at 21:45.
 
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jwlt500r

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I just had my transmission rebuilt and the kit i bought had the corvette servo in it. It shifts hard going into 3rd not really that bad but the guy who rebuilt it said it was because of that corvette servo.. What do you think about that??
 

rockola1971

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I just had my transmission rebuilt and the kit i bought had the corvette servo in it. It shifts hard going into 3rd not really that bad but the guy who rebuilt it said it was because of that corvette servo.. What do you think about that??
I think your guy that rebuilt is full of it. The servo itself does NOT "shift". Essentially what your builder would be saying is the reason a manual transmission shifts into third gear is because the shift linkage shifts it into 3rd...No the driver commands and manually manipulates it into 3rd via the gears shift. The valve body, PCM, Shift solenoids and other tranny internals do the "shifting" on an automatic. Your hard shift into 3rd could be caused by many things but I would suspect a ball missing, stuck or in the wrong place in your valve body separator plate.
 

rockola1971

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So do you think it's worth it? Kind of confused on what's the cause of the band burning up.
As you are launching in first gear the transmission is spinning up just like your engine is. The input drum is turning faster as your MPH increase because your engine is bolted to the torque converter and the input drum and converter are coupled together via a shaft. Other things happen that have to do with your PCM and inside the guts of the tranny that cause a command for 2nd gear. When this command happens there is a passageway in the valve body that is fed tranny fluid via your 2nd gear solenoid in the valve body that causes tranny fluid (used as hydraulic fluid in this case) to get on top of the 2-4 servo via passageway in the tranny case that ultimately leads to the valve body. This fluid fills up the space above the servo and pushes the 2nd apply piston (within the servo assembly) and that in turn pushes down on the unanchored end of the 2-4 band. Now remember this input shell along with the engine is spinning up faster and faster proportionally to the MPH of the vehicle. The band is trying to hold the input drum stationary and there is slippage until it does. The band is kept lubricated with tranny fluid at all times and the fluid also is used as a coolant via drawing heat away. The inside of the band (the surface that holds against the input drum) is basically clutch material. Looks just like the material on a clutch disc of a manual tranny.

This is a semi basic explanation, there are alot of things going on in a tranny during all the various gear shifts and also at various speeds and loads too. Tranny fluid does many jobs. Its a lubricant, hydraulic fluid, coolant and detergent for cleaning. The fluid does these jobs at fairly extreme temperatures and pressures.
 

Tonyrodz

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As you are launching in first gear the transmission is spinning up just like your engine is. The input drum is turning faster as your MPH increase because your engine is bolted to the torque converter and the input drum and converter are coupled together via a shaft. Other things happen that have to do with your PCM and inside the guts of the tranny that cause a command for 2nd gear. When this command happens there is a passageway in the valve body that is fed tranny fluid via your 2nd gear solenoid in the valve body that causes tranny fluid (used as hydraulic fluid in this case) to get on top of the 2-4 servo via passageway in the tranny case that ultimately leads to the valve body. This fluid fills up the space above the servo and pushes the 2nd apply piston (within the servo assembly) and that in turn pushes down on the unanchored end of the 2-4 band. Now remember this input shell along with the engine is spinning up faster and faster proportionally to the MPH of the vehicle. The band is trying to hold the input drum stationary and there is slippage until it does. The band is kept lubricated with tranny fluid at all times and the fluid also is used as a coolant via drawing heat away. The inside of the band (the surface that holds against the input drum) is basically clutch material. Looks just like the material on a clutch disc of a manual tranny.

This is a semi basic explanation, there are alot of things going on in a tranny during all the various gear shifts and also at various speeds and loads too. Tranny fluid does many jobs. Its a lubricant, hydraulic fluid, coolant and detergent for cleaning. The fluid does these jobs at fairly extreme temperatures and pressures.
Thx for the explanation, informative.
 

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