The problem start when i replaced the radiator .
you can think it'* related ?
maybe the transmission geting hot from some reasons ?
i asking because i got a BAD LUCK with this kind of problem , i can replace the PCS and the problem still continue .

can i do it without taking down the engine / transmission ?
take out only the wheel and the brakes system .

Well, since you replaced the radiator, the transmission cooling lines go through it, and could cause the tranny fluid temp to go higher than normal, if there is some blockage or a restriction.......

But methinks it is just coincidence.....this job is a pain, even on a lift, never mind on the ground.......yes you have to remove the axle, yes you have to diisconnect the intermediate shaft, yes you have to lower the cradle, quite a bit, I might add, and yes you have to support the engine tranny as you lower the driver'* side(this means the front of the car has to be jacked up significantly, so that you can lower the cradle and the engine/tranny),.......the reason for this is, because the valve body sticks outward into that side cover.....you need to lower it so you can get enough clearance for the side cover to be removed......

Have you even checked for the P1811 code? Or any tranny codes? When certain tranny codes are set, the default action of the PCM is to command full line pressure, which will in turn, cause harsh shifts....

We are not there doing all the tests with the equipment we would have, to give you an exact solution to your problem(for example, if I had this car in the shop, I would road test it with a Tech II scan tool installed, and would observe transmission slippage data when under a load....if out of spec, I would command full line pressure to check slippage),,,,,,,all we can do is make suggestions.....it is much easier to install the shift kit, as has been suggested.....that just involves dropping the tranny pan.....but once again, it is just a suggestion based on the limited info you have given us....

Today my friend told me that it can be the MAF sensor ..
what are you think about that ?

Today I connected the car to computer , the mechanic guy told me that in the history i got : P1811 , P1626
in addition he told me that he see problem with the MAF and MAP sensor

Today i saw under the transmission leak .
the leak coming from the transmission gasket .

the leak related to my shift problem ? (to remind , i got harsh shift when the car warming up).

maybe is a MAF / MAP sensor ?

i want to be sure that i'm not replacing the PCS for nothing ...

Eitan Welcome to the forum, MAF etc- is the car engine running smooth/ right any codes?
Leak on trans pan is it just a bit of a drip once in a while or a major leak puddle under car?
Regarding transmission...
I also had P1811 code first thing I did was to remove varnish in the valve side and bores of accumulator to see if that would help. Often varnish build up in the PCS and it is worth a try to get it clean before u drop the pan anyways. Use acan of trans tune first- https://seafoamsales.com/product/tra...uid-treatment/
Next-My recommendation since you have P1811 code is to drop the trans pan and see if there are any particles in pan. If not then to get a firm shift happening again without need for replacing the PCS at the valve body (which is much work) and follow the good included directions to install the Transgo spring & spacer kit into the accumulator, which is accessible once the trans pan is down. Easy to do and not expensive.
The Delco trans service kit comes with a filter & gasket.
Now you have a fresh seal and Use Dexron VI FLuid (6) to fill and I think you may find your transmission problems regrading shifting are gone.
This is what I had to do cause I sure had no time to rip into the valve body & with the transgo accumulator kit it works fine now, no more P1811 long adapt code anymore.
TransGo 4T65E: SK 4T65E




It took me 25 minutes once the pan was off to install the shift kit. Next was filter/gasket & 7.4 quarts of Dex 6 and done shifts great no problems no codes.
Note-I used 1000 grit Emory cloth in circular motion inside bores to clean them up.
Hope this helps.

Has the car ever given you problems starting?
That P1626 has to do with the theft deterrent systems fuel enable signal.

How did the mechanic determine there was a problem with the MAF and MAP?
Did he actually elaborate on why he thinks there is a problem with those sensors?

The MAF & MAP no turn on the engine light , but in the computer the mechanic guy saw both of them in minus .
he said that he never saw this before .
about the leaking is very massive ,all the pan wet , sure i'll fix it but you think that is the cause of shifting problem ?

The MAF readings are in hertz, a proper functioning MAF will smoothly go up and down in hertz, if the car is running nothing should be read as a minus, unless he was taking about the short term fuel trims, and even then it is normal for the short term trims to dip sweep from negative to positive, like say around -5 to +5, at least that is the values I remember, I'd have to go hook my scan tool to it to see the fuel trims..
I'd get some MAF Cleaner from an auto parts store, remove the MAF and spray off the little metal part you see at the tip, let it dry then put it back in there, even if it is not causing your issue, it is a good idea to clean this every time you change your air filter.

From my understanding he MAP is measured in volts, and they change voltage in relation to the intake manifolds atmospheric pressure while running, and right before start up they read the barometric pressure.
Did he say the MAP was registering 0 volts while the car was idling?

A bad MAP Sensor could cause the shifting problems you are having, but so can the fluid leaking issue, if you lose enough fluid it will slip and buck, I'd constantly check those fluid levels properly until you get the leak fixed.

Here is a good link for trying to test the MAP itself.
https://www.gmforum.com/trouble-shoo...sensor-280296/