bluebird71

iTrader: (54)

I am putting a Transgo HD2 and Vette servo in the 4L60 in my '03 Silverado. I already ordered the Vette servo, but now I'm wondering if I need another one as well. The description said "2-4 Corvette Servo" and the part # on it is A74907B. I assumed that "2-4" meant that it controlled ALL the shift points, including 1-2. I know there is an aftermarket 4th gear billet servo, so are there 2 different Corvette servos? Will this one help my 1-2 shift, or will I need another one on top of it? The item came with 2 individual pieces to it.

mrvedit

There is only one "Corvette servo" which has a bigger apply area for the inner piston. Many people call this the "2nd gear servo", but it is actually applied in 2rd, 3rd and 4th gears. There is a 4th gear billet servo available, but IMHO I don't see any reason for it unless you are track racing in 4th gear at WOT (120mph+).

Note that the HD2 kit specifies the WHITE Accum spring in Step 4 Page 2 for the Vette servo. Also I would recommend then drilling the 2-3 shift hole to .101 (Page 4).

bluebird71

iTrader: (54)

Awsome, thanks for the advice. I also went ahead and got the Sonnax servo release check valve to go in there as well.

mrvedit

Excellent choice. Note that with the Vette servo, the orifice hole on the release valve needs to be drilled to .120; I first drill it to .100 and then to the final .120. As instructed, I then drill the 2-3 feed hole to .125 (same as 1/8").

Note: The HD2 kit includes drill bits .082 and .091. You might want to buy .100, .110 and .120 ahead of time. I bought a complete set of bits from Harbor Freight.

If you want, PM me and I will be happy to give you my phone # in case you need assistance.