2005 Aztek Transmission

I'm hoping someone may be able to shed some light on a weird problem my transmission is doing in my Aztek. Here is what happens.

About once a week while driving I will notice that it starts shifting harder between gears. It doesn't slam or slip, just noticeably harder when shifting. The strange thing is if I shut the engine off for about 30 sec, it goes away. It may not happen again for another week or longer and when it does, shutting it off briefly always corrects it.

Could this be a computer related issue or something with the transmission itself? It was flushed and filled about 10,000 miles ago. Could it just be due to needing a new filter and fluid or could it be something else I need to look into? Thanks for reading!

Scan for codes first........also check fluid level/condition........

I have access to a Snap-On code scanner that I can get to tomorrow night after work. I have checked the fluid level and it is at the proper height on the dipstick. Also, the fluid is nice and red without any indication of burning. I'll report what I find with the scan tool tomorrow night. Thanks for the reply.

Scan for codes first........also check fluid level/condition........

Ok so after hooking up a code scanner to the Aztek, I discovered a code of P1811 (Maximum adapt and long shift). Can anyone shed some light on to what this means for me? Thanks!

Common code for 4T65E GM transmissions......when it sets, causes PCM to shift under full line pressure.....causing hard shifts....

The usual fix is replace the pressure control solenoid in the tranny......I said usual.....in some rare cases you might also need a valve body.....

Either case, a transmission service should be done after replacement(flush and filter).....

There are other fixes(shift kit) if you do a search for P1811 in this forum....

Thank you very much for the info. I will check into all of those options. Luckily I have a good friend that is a GM Master mechanic to get greasy for me!