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No 2nd Gear in 1997 GPGT

T

theedgeofsanity

New member
so, my '97 GPGT has 210,000 flawless miles on it and suddenly it seems to have a major issue. The trans has been slow shifting into 2nd gear for about the last 50,000 miles but I would never describe it as slipping - more like a slow shift instead. well, out of nowhere, the car seems to have lost 2nd gear. I can accelerate in 1st all the way to 30 mph, then the car goes to shift and its like its in neutral. Now, if I accelerate in 1st, I can get it to 30, floor it and it accelerates really roughly to 45 mph and if i let off the gas a bit, it goes into 3rd gear, then overdrive. This is what I observed by watching the tachometer. Now, I still have flawless reverse and 1st gears and NO service engine lights. Anybody have any ideas? the tranny fluid is full BUT is pretty dirty. Awhile back my mechanic said not to change the fluid because its supposedly bad for "high mileage" transmissions. What can I do to diagnose this better? is it common? I drive the car for work everyday and I don't know how long I can manage it like this!! My uncle has an OBD II scanner from craftsman - would this be able to tell me anymore info if I plugged it in while driving?
 


You'd need a scanner that can read transmisson codes, I doubt the craftsman one will be able to.

Its possible that 2nd gear is now gone.

But hey atleast the vacuum trans made it this long already. Its known for having many problems.
 
in the event that I need to replace the trans, what exactly is the difference between the 97 and the 98+? also, could it be a vacuum modulator or shifter linkage?
 
97 used vacuum pressure to control the transmission in certain ways.

98+ for GT's they dropped that and went 100% computer controlled.

Other things to look at is a shift solenoid. But scanning the trans first is what I would do.
 
Fist thing's first, check codes. If no codes, drop the pan. If it's toast, this won't hurt anything, and if it's good, there's still enough of the clutch material floating around in the trans for it to survive. DO NOT FLUSH THE TRANS. Look for shiny particles in the fluid and on the magnet in the trans pan. This would indicate worn steels in the trans as well as wearing gears/thrust plates/bearings. There will be some amount of clutch material in the pan. Clean it out. Change the filter. Test/replace the vacuum modulator. Basic things for this trans. Refill trans with Dexron 6. Pray.

This trans has gotten a bad rep through the years, but there are many still going. It's not typical for it to lose only second gear though. Have you tried manually shifting down to second? It could be a seal or something leaking internally. The other thing is, if it is dead, there are so many of these things out there, a used one can be picked up pretty cheap. Keep us updated.
 
well my plan for this weekend is to borrow my uncle's scanner - it does real time data and I recall using it on my alero and it saying if it was in lockup in a gear or not. also, it shows any pending codes or history codes which may help. i can't change the fluid until the beginning of may because I am up at school currently but, i can park it until then and drive my malibu instead. i simply prefer the grand prix over the malibu though! I have no intentions of scrapping this car - had it since I was 16 and want to see at least 300K with it!
 


My car ran flawless top swapped with that trans until I stripped the pump (I have no idea how...there's no load on it. OH WELL.) I replaced the pump and it's good, but I got a killer deal on a 5 speed swap so I'm doing that now. It is possible that you have a stuck 1-2 shift valve which does happen to these as well. That is located in the valve body which is in the D/S wheel area under the side cover. Another possibility is a stuck 1-2 accumulator or leaking accumulator seals which is located behind the valve body. You have lots of things to check, and as stated there are other options out there such as a used trans or whatever. Try shifting manually through all the gears a few times without driving. It's possible that there could be some crud blocking a passage. Good luck with it.
 
I would check the vacuum and modulator to start. Easy and free. The vacuum is what controls the pressure for shifting. In the later 4T65 transmission that is controlled by the PCS which commonly screws up. A pan drop and inspection is also good as mentioned. I'd add a quart of Lucas stop slip while in there.

Second gear is pretty beefy in these transmissions and that is why they don't typically fail. Also, most of people's driving is commonly done in third or fourth. This shouldn't be a shift soleniod, because all three other gears work. Your scanner should pick up any codes etc that exist.
 
weekend update: had more time to play around with the prix. I hooked it up to the scanner and there were no pending or history codes. also, I did get it to go into 2nd gear one time. it literally shifted like it normally would. I am now driving my malibu and parked the grand prix until I have more time to tear into it once school is done. I forgot to mention I checked all the fuses related to the transmission and they were good. Where are the vacuum lines that go to the tranny? I'd like to look at them!
 
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