Thread: 04 GP GT2 WT, Shifting hard & Making a wining noise (OMG! WTF! IS THIS?)

I just bought a 2004 Grand Prix GT2 Wide Track with anon/supercharged 3.8 V6 and a 4T65E Automatic Transmission. This car has101,000 miles on it, no leaks at all keep very nice at all times. Here is theproblem and I will try and get detailed as possible. I have noticed that on anavg day I will get in my GP start it, let it warm up a bit and leave and itseems to be if I drive my GP like a “Granny” i.e. very conservativestop&gos with no rapid acceleration than all is well other than regardlessof “driving habits” if I have to slow somewhat quickly I can feel/hear a bumpright before complete stop. Now it seems to be that if I accelerate rapidly orstart to drive the car aggressively the car will very apparently start to shifthard and nothing seems to make that system go away other than shutting off thecar and restarting it. And last but not least It appears to be that mytransmission is making a wining noise that goes with the engines rpms.(it makesthe noise weather the car is moving and when the car is in park and I’m revingthe engine.) Not a Knock or a Ping but a Wine. Alternator is new and good,along with all pulleys and belt. As far as my Transmission fluid it is a lilbrn ish but not “BAD!” and yes when I checked it the Stick left grey smudgingon the paper towel but I don’t know if the tranny has ever been serviced or notI want to think so because the is hand written with a yellow wax marker undermy hood on the rad/shroud “tranny 40k” but I really don’t know. Could it be aDirty Tranny making the Valve body not work right or the pressure solenoid notwork right or do I need to have it all rebuild? I want to keep this car aroundfor a while longer. How much I’m I looking at to have it fixed?

I've got a 2000 GPGT with a 4T65E that does the exact same thing. Runs smooth at first but once it gets good and warm and you come to a stop... the whinning and hard shifting starts. No way to stop it except to turn the car off and restart it. I've got just over 230,000 miles on mine so it's earned a rebuild, which it is getting next week. My guess is valve body. I bought mine pre-owned at 44,000 and I've changed the fluid and filter every 50,000 and always added a bottle of Lucas. These transmissions are not known for their longevity/durability so I consider myself blessed to have gotten this far with it. Sorry to hear you're having this trouble at only 100,000 miles, but there's no telling how it was driven before you bought it. Best wishes and set some money aside for a rebuild... I think it's in your not-too-distant-future.

Just got done reading this thread (4T65E Hard Shift-Solution) and it seems to be a great fix for our exact issue. I'm still going to get a complete rebuild because I have so many miles on my transmission, but I like the idea he gives about putting the cooler on and bypassing the radiator to keep tranny oil temps down. I will probably do this on mine after the build. Since you've only got 100,000 miles, you might want to try this before shelling out a bunch of money. Looks pretty simple and cheap.