TA98LS1

first off ever since i got this car 1st to 2nd gear shifted hard but it seemed right. Now within the last year or so it REALLY shifts hard , so hard that it seems like somthing is loose in rear end , feels like it moves the whole differential housing. Its not slipping that i can tell , but the best way i can describe it is when it shifts into second it acts like i took my foot off gas and and back on , you can also here this happen in the exhaust(it cuts out for that split second).
So far i have replaced filter,1-2nd shift solenoid, and fluid.
The car shifts perfectly under WOT , the problem happens every time below 100% throttle , no matter if im giving it 5% to 90% throttle.

not sure if this could be tune related but here is my current tune, thanks for any help.

TA98LS1

Hasn't happend the last few times I drove it , I haven't changed or fixed anything WTF!

performabuilt

iTrader: (25)

Could be an issue with the presure control solenoid or you could be setting a code 1870 occasionally this will cause max line

TA98LS1

Not throwing any codes , where is the pressure control solenoid , is it in the pan?

Gilbert@Ace Racing

The PCS is located inside the pan on the valve body. Before you replace it I would suggest having a reputable transmission shop diagnose the condition as you might be wasting time and money by replacing the solenoid, and who wants to do that right?

I would recommend logging any trouble codes and then removing the positive battery terminal and touching it to the negative terminal. That will bring down any memories stored in the PCM. Then after about 30 seconds of doing that go ahead and run it again and see if it acts up.

If it does, and you've had any tuning done then you might want to contact your tuner to see if he has turned off any transmission codes.

If you would like to discuss it in detail feel free to give me a call!

g

TA98LS1

I have HP tuners and just checked my dtc and code po478 is set to no error reported and ses is disabled. Should I enable this code , I compared it to other 98's in the tune repository modded and stock tunes and they are all set to no light no ses.

Gilbert@Ace Racing

Okay now we're getting somewhere.... thanks for that info. Indeed that is a Pressure Control Solenoid code.

Now, it could be that the solenoid itself has failed and simply needs to be replaced. But, there are some filters in the valve body that might be clogged up and are causing low flow and subsequently that code.

But... if the car is equipped with a vacuum modulator instead of the PCS then it is possible that the vacuum line is off. I want you to look at the transmission. Specifically look at the passengers side of the case immediately behind the large round electrical connector above the pan rail.

If it has a vacuum modulator, it will have a brass nipple protruding from the case right behind that connector. If so, look for a hose coming from the brake booster vacuum supply hose. There will be a plastic T in that line that provides a vacuum source for the tranny. If it has all of that, look for a break in that hose.

Hope that helps....

g