Neil

I see that some of you guys are getting frustrated with the infamous vette servo. This servo is a definite improvement over the stock servo, but in addition to this I would focus on the 1-2 accumulator spring. I see that a few of you have heard of the "washer" trick, well I went a few steps further. I removed the spring completely and used a metal sleeve which fit around the piston shaft. The whole purpose of this spring is to allow the piston to travel backwards in the bore (tranny fluid pressure forces it back), which will allow for a softer, slower shift. The stiffer the spring, the less the piston travel = a quicker, firmer shift. So, throw out the spring, check and make sure the piston & piston ring are not worn, if they are replace them - very cheap. Next, get a metal sleeve to fit over the center piston shaft, brake line tubing will work. Oh, make sure the piston is in the bottom of the accumulator housing (use petroleum jelly to coat the new piston ring and the inside of the bore)!!! Cut the brake line so that the it is almost flush with the top of the housing. If it sticks out of the housing you will damage the separator plate. Also, I woul d position this sleeve so that the flared end is in contact with the separator plate. This is a cheep mod, and I guarantee that you will feel a difference! Remember, if that piston is allowed to move with fliud pressure then your shifts will not be as hard.
I did this same trick with the 3-4 accumulator bore/spring and it definitely helped firm up that shift as well.


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Neil 383 IROC-Z: TFS heads/JE pistons 10.8:1/ 24lb/hr SVO inj./ Edelbrock Runners&Base/ Strange 12Bolt Diff./ Neil's Home-Built BulletProof 700R4+Vigilante 2800 stall converter & much more.........

tf0r1

wow, thats some killer info, Im just affraid to f with my tranny, still being under warrenty and all---but now I have a mechanical understanding of how it works---dude! Thanks!

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(Kill the headlights, and put it in neutral)

--George
92 RS 25th Aniv.
350 Goodwrench (NEW LO5)
700R4 Raptor: high performance intermediate billet servo, high performance overdrive billet servo,Mega Valve,13 vane high performance pump,1800 heavy-duty stall converter and a 29 element heavy-duty forward input sprag.

GMTech

Solid? Sounds like a neck snapper! J/K

That will definatly do it, I considered something similar, but didn't want someting that drastic.

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'87 Trans Am
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Corvette Servo,
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'97 Bonneville SSE

IROCKZE

I had to back off a little and put the spring back in...the 1-2 was SO hard I was afraid it would snap my u joints. Now with the Vette servo it's just right, barks and spins when I get on it, firm but not rough when cruising around.

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85 IROC,5.0 TPI,T-Tops,fully loaded,black with red Lear-Siegler "Camaro" interior,Decal Delete,91 Bose stereo,Stage 2 Fastchip,AFPR,TB Airfoil,K&Ns,March pulleys,Alum. Driveshaft,92 police version 700r4

"The Devil drives a Camaro"

Pro Built Automatics

The 1-2 shift should get progressively firmer with more throttle when set up correctly. If the shifts are to firm at light throttle, then the accumulator in the valve body is most likely mis-matched to the 2nd gear servo, rear end gear ratio, etc. The Corvette servo will show up the mis-match more than the 553 servo. The accumulator in the valve body has to do with apx. 1/8 -5/8 throttle opening, and the accumulator sitting on the valve body plate has to do with 3/8 - WOT. As you see they overlap. There are seven different accumulator valves, firm to soft light throttle shifts thay are as follows. "B" - "A" - "N" - "M" - "L" - "K" - "F". This letter is found on the back side of the accumulator valve. "M" works well with 3.73-4.11's, "N" works well 3.23-3.42's. This gives the best part throttle & full throttle shifts. The accumulator that sits on the valve body plate likes a fairly stiff spring to give a clean WOT shift. This information is correct when the 2nd gear feed hole in the valve body plate is .086 - .096. If you drill the hole to what Superior or B&M says you will have way too firm of a shift and is not necessary (premature wear & breakage on the gear train). As you see there is a lot too this.
Hope This Helps!!!