2007 Monte Carlo LS 39k

I'm having a weird issue with my transmission and I've taken my car to the shop a few times and the issue cannot be duplicated by the mechanic. I have had the trans flushed and check and nothing has been found. I also have not received any engine codes to back it up.

The issue begins sometimes when I start the car after its been sitting for a long time. When I accelerate from first gear the engine will rev almost like the transmission is slipping and then suddenly kick into gear hard (thump) ... Now I've been trying to figure out what the problem is myself but cannot seem to find out what is causing this because for starts it's not consistent meaning it does it only sometimes.

 

Before I had my transmission rebuilt, every once in a while, when I shifted from park into gear, if I didnt give it a few seconds to fully engage before hitting the gas, it would slam into gear. My problem was the pressure control solenoid in the transmission. I would assume you have the 4t65e trans. I found this to be a common problem on the 4t65e trans by doing a lot of searching on the web. Aparently the PCS can get clogged with dirt, causing it to fail and not properly regulate the pressure in the trans. Not only does it cause slow, sloppy shifts, but it will not build proper pressure at high RPMs like when you floor it and downshift. That was ultimately the death of my transmission. At 38000 miles too. If you have not had your trans slip while accelerating, I would say you could probably get away with a new PCS and fluid/filter change. Mine was too far gone by the time the problem was found. Have the trans shop do a line pressure test on your transmission. They should be able to tell if your trans is opperating at the correct pressure. Thats what I was told to do. Never got to do it though, trans ate itself up before I had a chance to have it done.

 

cool thanks ... i will go and do that ...
also would it matter that I have aftermarket rims on my car 22"? They are about 80lbs. (rims and tire) weight each compared to my old tires that were 45lbs. could that be adding to the problem?

 

It would not cause the symptoms you describe, but big heavy wheels are never good on a transmission, especially a FWD trans in a big heavy car.

 

Thank-you! I'm going to go check out this pressure test and pcs

 

hey buddy!! have you fixed your problem with the tranny? if you have can you just let us know how?

 

i have noticed whether on cold after its been driven for a while that every once in a great while you can feel the thump in shifting. mostly 1st through 3rd. its nothing really bad right now, but i know over time it will grow into a major problem. last time it started doing its thing a drove straight to the trans shop iv heard lots of good about near me. pulled up left it running, grabbed the tech, he hopped in driver seat. tell me why it drove like a champ? i dont know. then deja vu the very next week.

 

89k miles since I posted, it's slipping and thudding bad time for a rebuild ... Took it to Vegas 3 times and to San Francisco built pretty tough considering it's been having problems since 39k miles ...

 

Generally,
These transmissions after 80+ thousand miles begin to develop issues that wont go away.... Usually means its time for as rebuild... One of the drawbacks unfortunately of these transmissions...

 

itseems that alot of old members are returning....awsome