I have 140,000 on my 00 SS. She seems to shift hard when it's cold but after she warms up she shifts smooth. I get 1-2 gear shift around 20-25mph but 2-3 gear shift doesn't hit until around 48mph. Does this seem right? This tranny, 60k, went in last summer and shifted fine for the longest time but when it started acting up the service engine soon message came on along with the check engine light. Cleared codes no lights then first time driving again the shift occurred & lights came back on. The fluid is still clean as was the old fluid from donor car when I put the tranny in & no shavings.

 

Next time the CEL comes on have the code(s) read. It could be a problem with the transmission, or you could have another problem causing the erratic shifting. The codes will help to point you in the right direction.

 

What codes are you getting out of the computer? These transmissions seem to have a common problem with the solenoids. When they fail, the computer maxes out the line pressure to try and save the trans so it doesn't slip between shifts. That will cause your hard shifts.

 

X2 on the solenoid issues....

Im Hopeing you didnt use the same trans fluid from the donor car, and replaced the filter during the swap. and used new trans fluid...

Im not sure on yours:

But to replace the solenoids on my 1999 it requires dropping the trans to change out the solenoids.

This may also be a possibility, Maybe the donor car had the trans fluid done at an oil change place...(Thats a big no no) They reverse flush the trans thru the trans lines...and its not a complete flush anyway...What ends up happening it also ends up crushes the filter. This plugs it up. and prevents it from filtering the fluid properly!
I learned that the hard way and with in a few miles I started haveing transmission issues.....
So, I immediately went to a trans shop and explained to them what I had done...They just looked at me like I was an idiot for doing it that way....
Thus haveing them do it the proper way (dropping the pan) and R and R'd it. Eliminateing the problem. (they showed me the crushed filter) It was made out of plastic!

I would recommend going to your local trans shop and have them Scan your trans and see just whats going on. (as before mentioned by 03SSLE)

 

I have no idea on if the old fluids were used. I did a code check this morning and got 4 codes. P0403, P0405 & P0420 I got twice, all having to do with the EGR. Nothing for the trans.

 

Not all scanners are capable of reading all powertrain codes. A Tech II or equivalent scanner is required to retrieve transmission codes.

 

In regards to your initial question on shift points; there are a few variables that control the shift, speed, RPM & throttle position.

Attached are tables from my HP tuning software on a 2005 SS

 

1st attachment showed up small, let me try again...

http://lohinc.com/trans.png