99_ls1_z28

iTrader: (8)

I bought this car two months ago,and the previous owner told me that he UP the line pressure on the transmission. All this time it had driven perfectly fine, the shifts were a little noticeable, but not hard . But Yesterday when I shifted from Park to Drive it Jerked forward HARD, first to second, shifts fairly hard also and you can notice the rest of the gears shifting also. I checked the Transmission oil and it read on the Warm part so I added some more oil, but the problem its still there. It shifts fine, just hard. I went through all the gears at WOT and if shifts fine. Have anybody had this problem??

TXZ28LS1

iTrader: (5)

i would assume that is normal. if the tranny is shifting good, and not banging the rev limiter and the oil doesnt smell burnt it should be fine. when i was all stock it would shift from park to drive or to reverse smooth and quiet. then i added a stall and cam and the tuner up the shift firmness/pressure shift points and it does some of the same stuff u mentioned. now i have a stage 2 tranny and it still does it.

99_ls1_z28

iTrader: (8)

It would be normal to me if it had been doing it all the time, but it just started doing that. So I assume something is wrong. I wonder if the Pressure Selenoids are bad?

FLT

iTrader: (1)

It might be possible that you have a code that has been thrown that is causing this. Some trouble codes will put the trans in a max line pressure condition. I would get a scan tool on it to see what is going on. Vince

99_ls1_z28

iTrader: (8)

I went to Autozone and had the codes checked and two popped up. Its a P0442 and a
P0102

FLT

iTrader: (1)

Did a quick search here and this is what I came up with for code descriptions.

DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency
DTC P0442 Evaporative Emission (EVAP) System Small Leak Detected

I think that the mass air flow code is what is causing your trans to act the way it is. I have seen this happen multiple times while in this business. In most cases it is dirty or has oil on it from the air filter. I think this is a good place for you to start. Vince

FLT

iTrader: (1)

Take a look at this thread for the P0442 code you have. Post #2.
https://ls1tech.com/forums/showthrea...42#post3848266

99_ls1_z28

iTrader: (8)

I tried cleaning the MAF, but its still doing the same thing. Is it a good idea to reset the computer after I cleaned the MAF? Can a header leak cause this also?