Servo question.

[Jordan836]

Alright so in about the next week or so I plan on buying some vette servos and a transgo HD-2 shift kit my question is should I buy the billet 4th servo, or just keep the stock one?

[timber74wolf]

I have just the corvette servo in my truck and it shifts a tad bit harder than stock. I am slo thinking about the Shift kit just to prolong the life of the tranny. Or I will just get a tune done to make the tranny shift harder than it is now. On the 4th billet servo what will you gain by installing it? All I heard so far is it will allowyou to lock the torque converter up at wide open throttle. is this true? And what other advantages can you gain with the 4th billet servo?

[Vince_B]

On the 4th billet servo what will you gain by installing it? All I heard so far is it will allowyou to lock the torque converter up at wide open throttle. is this true? And what other advantages can you gain with the 4th billet servo?

The 4Th servo really does not relate to lock up. It's function is to apply the band to make OD happen. Now lets take this a step further with installing a sonnax servo in this location. This info comes from Sonnax.

"Vehicles with a 4L60 (700-R4) or 4L60-E transmission often exhibit poor 3-4 shift
quality and experience band failure in performance applications. The Sonnax "Super

Hold" 4Th Gear Servo features 40% more apply surface area for greater holding power."

Features & Benefits:
• 40% more surface area for greater holding power
• Affects 4Th gear only
• Can be used with OEM, Corvette or Sonnax performance 2nd gear servo assemblies
• Easy to install: Transmission removal is not required

To see more info for the install visit sonnax.com

IMO the reason for this piece is to add holding power for the band in the OD position. When cruising down the highway it will increase the amount of fluid holding the band and keeping it applied. Lets say your transmission line pressure is at 100psi at 70mph. With 40% more surface area that is like having the pressure at 140psi with a factory servo in the same conditions. Now with that being said your pump is not working as hard and there is less strain on the engine. I think that probably frees up some load on the engine and definitely is not hurting anything. I hope this helps. Vince

[Jordan836]

Awesome that was perfect. Thanks alot