99-LS1-SS

I bought a 99 SS a few months ago. The guy I bought it from was the second owner. He said he serviced the transmission and said it has a Red converter in it(I assume it is a Yank but I am not sure). He couldn't tell what the stall was. My concern is, my car shifts very hard from 1 to 2, but not any other gear. It also locks up very hard(It makes a clunking noise when it the converter locks up). Does anyone have any idea what could be causing this and is it bad or normal? I haven't ever had a car with a after market converter in it so I don't know what to expect.

99-LS1-SS

(sound of crickets chirping)

Dom

iTrader: (2)

Clunking noise? Maybe it's a Super Thruster? Mash the gas pedal off the line and see where the RPM are at when you start moving. Make sure you dead hook.

99-LS1-SS

That is the sound it makes when the converter locks up. It locks up as hard as it shifts from 1st to 2nd gear. But it doesn't do it in any other gear.

What does "dead hook" mean?

Colonel

To dead hook mean to launch with absolutely ZERO tirespin.

It sounds to me like the line pressure has been turned up on the 1-2 shift. There are a few ways this could have been done.

99-LS1-SS

I wasn't aware that you could turn the line pressure up just between 1-2 and no other gears. Can I turn it down or is that something I shouldn't mess with?

Dom

iTrader: (2)

You probably have a shift kit. Most shift kits increase the 1-2 ALOT, then 2-3 is softer and 3-4 it unnoticable.

Colonel

Shift kits some with washers that you can shim the accumulator piston with. That'll raise the 1-2 shift firmness without effecting the others.

99-LS1-SS

Well having heard you're comments. I have also heard that too much line pressure is very bad for a transmission. I have the HPP3 with the shift firmness up 25%. Is that going to cause a problem?

Dom

iTrader: (2)

I am all for increasing pressure via hardware not software.

Colonel

I agree with DOM. I'm not confident that adjusting line pressure by way of the PCM is the best thing to do (and it really doesn't help WOT shift much if that's what you're looking for.)

You might alleviate your hard shifting by setting the HPP3 back to stock. Other than that I would have a tranny expert check to see if you have a shift kit in there if it really bothers you.

WILWAXU

iTrader: (6)

I agree.. Adjusting the line pressure in the PCM is a no no in my book.

Hawkn01

iTrader: (1)

Sounds like he has a transgo shift kit in it with three washers(firmest setting) in the accumilator. Take to a tranny shop and have them remove 1 or 2 of the washers.The more washers you remove the softer the shift.