Thread: 03 trans into a 99...

Found that post finally I see. Can it be done, well John said he did it and it worked. A couple other guys tried it and said it kinda worked, but not well. Tough to say w/o trying it.

This guy has a bunch of posts about this at GMforum.com, I had pointed him to NEPontiac.org to look up the pin swap that you mention above. However...he had issues.

Originally Posted by xtremerevolution

I need to know if a 99 year Pressure control solenoid will physically fit into a 03 4T65E transmission.

I think I figured out my transmission's problems. I'm using a 99 PCM and an 03 4T65E and people suspect that the reason my transmission doesn't shift properly is because the 99 PCM can't communicate properly with the 03 PCS. I have heard that they are electrically different. It will slip into gear unless I raise PCS pressure, but the shifting is erratic at times and the car goes into limp mode within 15 minutes of driving with no other explanation.

So, will that PCS physically fit into the transmission?

More on it with the link to NEP
Need transmission tuning help! - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat

Pay attention to the dates of the posts as it can become confusing and then ensure you see page 8 where he talked to Dave abotu the pcs being different
03 4T65E slipping in 1st - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat

this is all why I suggested swapping the valve body/channel plate in the pm.

You'd need to compare the pcm pinouts. I'm surprised the trans connector is different, my understanding from the posts was that it was the same connector and you may be able to swap pins... Unless you are talking about the black block at the back of the trans, that's the range switch, which is easy to take off your old one and put onto your new one.

use this to find out how to line up the switch when you add it on.
http://www.grandprixforums.net/how-a...ion-49297.html

Or get some extra trans connector pins and add them in for the internal switch. But I think you still need the external because your starter soleniod is routed through it.

Great...glad to hear it.

Test Run sucessful, i can verify that i used an 03 trans from a GTP into a 1999 series II 3.8 SC Regal GS using the pinout scheme above and my PCM which is tuned (but only on the engine, nothing in the trans tables were modified) At the moment i have not done any hard runs, but the normal run was successful, i will update if this changes. Thanks Jeff G