So before the pcm change transmission worked fine? After pcm change transmission wont work. Correct?

 

Yes the trans shifts fine goes in and out of overdrive fine no slipping. when going from neutral to drive it only take a sec to go into gear.

 

Oh yess they are! But, it is nice to pop an engines cherry. Greatest smell in the world! Especially if its a Hemi!! haha anyways, I might have to deal with breaking in an engine. Not sure yet tho.

 

Hi Robert,
Sent you a PM w/ some GM tranny questions. THANK YOU.

 

If lock up and overdrive are working fine. i dont think you have anything to worry about. Clear the codes and see if they come back.

 

Ok this may sound stupid but how can I tell if the trans is going into lockup? What does lockup do?
It only goes into lockup in 3 and O/D right?
Now If lockup is what I think it is mine goes in. When the trans is locked out of O/D just after it shifts into 3 it sounds like it shifts again like it went into O/D but it did not then when I turn O/D on it shifts once more so I think it is going into lockup. Also how do I clear the code? I tryed to unhock the battery for 15min but the code is still there. Do you think I should replace the sensor just to be safe? I am going to take the pan off to put a deep one on anyway. Thanks for all your help.

 

MonteC, I asked a question a couple pages back about my tranny holding in first longer before shifting into sec. Well I had to drive my truck over to a buddys house to check all codes to see if I was missing anything else. I find the reason for the higher shift is it has no second. It goes from 1st -3rd, can't even manually put it in second. And it turns out buddys computer doesn't have the right number chip to read all the codes. Is this more serious than previously thought?

 

Yeah that is correct

 

Thanks for the continued help. Went through the whole thing again to the best of my ability. No leaks now with a new pump housing.

I haven't taken it in to use a scan tool yet to check out this "limp mode" problem, and now another problem developed. Originally, it would start in 3rd gear, and would manually shift into first and second. Wouldn't go into o/d. This was described to me as the limp mode. Now, however, it will only go into 1st gear.

It did this all of a sudden, I was driving in 3rd, when all of a sudden it started revving reallly high as it switched to 1st.

Funny thing is, when I have the selector in 1st, you can tell it's actually in gear. When it's in 2nd or Drive, it will only go in 1st gear, but it kind of coasts when you let off the gas, and has no engine braking.
I know it's hard to diagnose these problems online, but in your opinion, do you think this would be related to the electric "limp mode" issue still, or does it sound like something took a dump in the valvebody?

I'm looking through the valvebody as i'm typing this, and as far as I can see all the internals look normal?...?

 

Yep from what you describe its going into lockup. To change that sensor you have to change the o/d and lockup solenoids, along with the entire wiring harness inside the transmission.