Transmission shifting problem

[raidermark]

I'm having a problem with my 2003 Chev Impala, 3.8L, 120K. The transmission has a very hard & premature shift when accelerating from a stopped position. It does this after it's been running a while. It seems to clear if I manually shift from 1rst thru to normal Drive. I've done 4 fluid & filter changes so the preventive maitainence is to schedule. Any thoughts? Is there a throttle position adjustment for shift changes like there is on older vehicles?
Thank you

 

[jorton]

I think shifting is controlled electronically. Neighbor recently had his cars transmission replaced. I remember he said the job included diagnostic check for faulty sensors. You might get that check if you know of a good shop.

 

[hate2work]

Try unhooking the battery for 30 minutes or so. Then drive normal so the computer can re-learn.

The above is just something I've heard others do, maybe it will help you as well.

 

[raidermark]

Thanks, to both responses. These sound like good ideas & good place for me to check. Thanks again.

 

[eljefino]

Stuff like line pressure is run off pulse width solenoids with default being firm shifts. You might have one getting weak. Also check all the wierd fuses (like LPS) in all the fuse boxes you can find.

If you have the 4t65E the solenoids are under a side cover and need quite a bit of work to dig out.

 

[backyardmech]

Try unhooking the battery for 30 minutes or so. Then drive normal so the computer can re-learn.

The above is just something I've heard others do, maybe it will help you as well. [/quote
]
If you do this you should start the vehicle without giving it no gas (keep trying till it starts)then let it idle for 15 minutes, shut it off restart it and then drive it normal. Atleast thats what I was told. Its becuz the ECU has to relearn how to run the engine first

 

[Ryan]

Is it shifting hard through all gears after a while? If you cut the car off for about 10 minutes, does it shift normal again? The most common problem with the 4T65E is the pressure control module, which controls how hard the car shifts will bind up and slip, causing the transmission to compensate by increasing line pressure to max. 03 and up 4T65E's have a revised PCM because of this problem, but there are still reports of it happening. Let me know if these are your symptoms. I have an 02 Olds Intrigue and had that problem. I put a Trans Go shift kit in it and KNOCK ON WOOD, it hasn't happened since then. We will see how it works throughout this coming summer, as heat usually causes the PCM to bind up. I hope it doesn't give me anymore problems.

 

[raidermark]

No it is not shifting hard thru all the gears. Just the first gear & only after it's been warmed up. It'll shift too quickly & with a hard pop on the first shift.