Vette Servo... Hard 1-2 Shift.

[JoeRags]

2008 GMC Sierra, 5.3 with sport suspension package. 3.73 gears out back. Only performance mod so far is GMPP sport exhaust.

I have 48,000 miles on the truck. At 40k I dropped the pan, replaced the filter and filled with Red Line D6. Last week I put the vette servo in and I'm a little upset with the 1-2 shift. 2-3 and 3-4 are beautiful - HUGE improvement over stock... but 1-2 is really starting to bother me. If I get on it off the line, first shift will give you whiplash.

 

Anybody else experience this? Did I do something wrong?

 

Thanks

Joe

[mhenshaw]

Did 1-2 shift hard before the vette servo? Mine stock would sometimes shift hard if I barely let off the gas from 1-2. The corvette servo just made it worse. But Edge and Blackbear both fixed the irracting shifting.

[MS3DALE]

I was going to ask you if you had a Black Bear tune,If not I highly suggest one,Justin can tune your truck accordingly for the Vette servo.

And actually if you have Justin tune it you really don't need the Vette servo,He can firm up the shifts without it.

[dlstewart01]

I have the Sonnax version of the Corvette servo. It actually holds the bands 18% tighter than the stock Corvette servo. With a little transmission tuning with the Diablo Predator, mine shifts perfect.

 

I also run nothing but Dexron V1 in my trans. its the best fluid I have used and that includes Mobil 1 synthetic fluid.

[ChevyTech77]

That is what the Corvette servo is for, to firm up the 1-2 shift.

[GMstrong]

^ exactly.

[zx6r speedfreak]

i had the same issue, the only time i liked it was when i was racing someone. I then got a black bear tune and i am very happy with it.

[THE BIGPUNN]

Excuse my ignorance! what is a vette servo? and why would you put one on your truck?

[jro909]

Excuse my ignorance! what is a vette servo? and why would you put one on your truck?

 

 

its a 20 dollar part that pops into some spring thing in the trans, it firms up shifts...i've read that it will wear the internals of the trans out faster but who knows

[tonygxp]

these are the Sonnax servos

 

they go in place the factory servo which can be seen here to the left on the trans, that circular cover, they go there..

as for the op, who put them in? if they're installed incorrectly you can crack your case and it will shift like a "whiplash" style shift. if it's not seated properly. or there's a tune in there already, needs to be dialed back when you install the billet servos.

[mhenshaw]

Excuse my ignorance! what is a vette servo? and why would you put one on your truck?

 

 

Its the factory shift servo that comes in the old corvette's with 4l60. If shifts the transmission faster and more firm. It does the 1-2 shift and the 2-3 shift. The 3-4 shift is left the same.

 

It actually prolongs the life of the trans because it reduce slipping of the clutchs and in turn reduces heat. However it can be harder on the rear end.

 

It installs in 30 mins and cost $20. Most drivers expect a firm, fast shift in a performance car but in a truck they would think something is wrong and would want their truck to drive smooth like a car.

[tonygxp]

Excuse my ignorance! what is a vette servo? and why would you put one on your truck?

 

 

Its the factory shift servo that comes in the old corvette's with 4l60. If shifts the transmission faster and more firm. It does the 1-2 shift and the 2-3 shift. The 3-4 shift is left the same.

 

It actually prolongs the life of the trans because it reduce slipping of the clutchs and in turn reduces heat. However it can be harder on the rear end.

 

It installs in 30 mins and cost $20. Most drivers expect a firm, fast shift in a performance car but in a truck they would think something is wrong and would want their truck to drive smooth like a car.

 

 

you make it sound so simple. i have seen more than one come into the shop with cracked trans cases due to improper installation. do it yourself and hope you get it right or it is extremely costly.

[mhenshaw]

Excuse my ignorance! what is a vette servo? and why would you put one on your truck?

 

 

Its the factory shift servo that comes in the old corvette's with 4l60. If shifts the transmission faster and more firm. It does the 1-2 shift and the 2-3 shift. The 3-4 shift is left the same.

 

It actually prolongs the life of the trans because it reduce slipping of the clutchs and in turn reduces heat. However it can be harder on the rear end.

 

It installs in 30 mins and cost $20. Most drivers expect a firm, fast shift in a performance car but in a truck they would think something is wrong and would want their truck to drive smooth like a car.

 

 

you make it sound so simple. i have seen more than one come into the shop with cracked trans cases due to improper installation. do it yourself and hope you get it right or it is extremely costly.

 

 

 

Yea, I have seen and heard of a couple people on the forums messing up too. But there is a lot of room to do this under the full-size trucks. You can almost stick your head up there to see if the snap ring is in place. (If you don't know about the snap ring problem - well some people destroyed their transmission case because they didnt get the snap ring fully in place and the pressure of the trans blew the cap off and cracked the trans case)

 

As far as the install there are videos on youtube that show you how it goes back together.

 

I heard this can be hard to do with the limited room under the tbss.

[RaddHazzard]

I would wonder if it was the Redline fluid along with the servo. Ive done the servo and none of my shifts are "hard". Firmer than stock yes.

Also the snap ring took me a bit, only because the case wasnt pressed in far enough which i didnt know at the time. Its not hard and you will know when the snap ring is in correctly, because anything other than correct it will fall right out. For me anyway.

[brainpause]

I have installed the servos as well. I have a Wait4mePerformance tune, done prior to the servos. I like the firm shifts, especially WOT from a stop. even at slow speeds, I like the crisp shift. but I wouldn't classify it as neck snapping.

 

Larry