Transmission problems??? [Archive] - GrandAmGT.com Forum

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Big Hood GT
03-05-2007, 02:40 PM
My '00 GAGT shifts great when it is cold and gets progressively worse as the engine/tranny warm up. Once everything is warm if you floor it, when if shifts from 1st to 2nd at redline, it takes probably 2 seconds to actually go from 1st to 2nd. It literally sounds like a stick shift that somebody is learning to drive, it cannot be right. I took it to AAMCO and had them look at the fluid (said it was clean and full), they hooked up the diagnostic computer and said there wasn't any trouble found. I've put 24,000 miles on this car and I know that when I first got this car it did not shift this way, 1st to 2nd when when floored at 46,000 miles when I bought the car was quick and crisp, it only has 70K on now and shouldn't be taking this long to make the shift from 1st from 2nd. Any suggestions would be greatly appreciated.

gectek
03-05-2007, 02:47 PM
ok well ill jump in first, i had this prob on mine, it was a combination of burnt clutches and bad bonded pistons and worn trans/engine mounts. so looks like an overhaul and check your trans mounts to make sure they are ok

Big Hood GT
03-05-2007, 02:54 PM
Thanks for the quick update, do I dare ask what the trans overhall cost?????

gectek
03-05-2007, 02:58 PM
well i dont want to plug my own work, so i will say it can range anywhere from $1200 on up. the only prob with an overhaul from a trans shop is they wont have all the options/products that i have for your trans. you can check out my trans build sheet thread in the all go section, and i can email it to you, just PM me, but i have heard on the estimates anywhere from $1200 to as much as over 2300, but if you need something in the area, or are appauled at my shameless plug, then i would def call around, and ask around also, if you talk to enough people they can point u in the right direction

Big Hood GT
03-05-2007, 03:05 PM
Not at all appauled by your thread, thanks for the heads up, if you could, e-mail your build sheet to me at tdogultra@yahoo.com. I'm pretty mechanical, but have only done minor work on transmissions, I do however have a friend who own's a speed shop in my town that could probably help me with the rebuild with your parts if that is an option. Check out http://www.racersedgemidwest.com/

TDRDevelopment
03-05-2007, 03:15 PM
I bet you have a problem with your Transmission Fluid Pressure Switch. Its a common problem with the 4t40e and 4t45e trannys. The TFP switch is a module that is bolted to the transmission valve body that senses fluid pressure when the transmission shifts and tells the PCM that the trans has actually shifted. The little pressure switches inside the module go bad and tend to work intermitently. I beleive there is a Technical Service Bulletin from GM for this problem. You might want to check it out. Could save you a lot of money by not overhauling the whole trans.

gectek
03-05-2007, 03:18 PM
sheet is sent. also, you dont just have to take my advice, but thats the prob i see alot

gectek
03-05-2007, 03:24 PM
I bet you have a problem with your Transmission Fluid Pressure Switch. Its a common problem with the 4t40e and 4t45e trannys. The TFP switch is a module that is bolted to the transmission valve body that senses fluid pressure when the transmission shifts and tells the PCM that the trans has actually shifted. The little pressure switches inside the module go bad and tend to work intermitently. I beleive there is a Technical Service Bulletin from GM for this problem. You might want to check it out. Could save you a lot of money by not overhauling the whole trans.

but usually those include the DTCs...but a good place to look, and that isnt too hard to replace, but even with those problems, the damage will be done even if you change the tft out...but by all means check it all out

bwwelk
03-06-2007, 01:07 PM
well i dont want to plug my own work, so i will say it can range anywhere from $1200 on up. the only prob with an overhaul from a trans shop is they wont have all the options/products that i have for your trans. you can check out my trans build sheet thread in the all go section, and i can email it to you, just PM me, but i have heard on the estimates anywhere from $1200 to as much as over 2300, but if you need something in the area, or are appauled at my shameless plug, then i would def call around, and ask around also, if you talk to enough people they can point u in the right direction


Hey could you possibly email ur trans build sheet to me also , i talked to you about 2 months ago and you had told me to check my mounts , from what i could see there was nothing wrong , my car is doing the exact same thing that the other guys is doing.. Thanks

bwwelk
03-06-2007, 01:10 PM
Opps ! My email is bwwelk@yahoo.com

bwwelk
03-06-2007, 01:13 PM
Also where exactly am i to look for the TFP switch on the trans .

gectek
03-06-2007, 01:35 PM
it is inside the side cover. the one i offer is the upgraded version also. ill get the sheet sent to you. the tft has 5 sensors and 1 temp sensor. but the newer(04 or 05 and up) have only 3 sensors and 1 temp sensor.

its sent

02GAGTinprogres
03-06-2007, 06:06 PM
can you send me the sheet as well i am interested in fixing this problem. furthermore, my rps jump all around and what not when i get in the gas. it also seems to stick in gear from time to time. if i disconnect the IAT sensor all together, where it boosts the line pressure it shifts ok, but the rpms still hop around. it threw a p1374 code which was Manufacture control system or ingition misfire but thats all it told me. i called a friend with a lot better scanning program and he said it was a cam position sensor. i replaced that last night along with a new, connected, IAT sensor. still does the same thing. i have flowmaster exaust and it sound like puffs of air in it. could it be the crank position sensor or what...any advice from ANYONE will be appreciated. thanks

gectek
03-06-2007, 07:05 PM
send me ur email

gectek
03-06-2007, 07:20 PM
also the 1374 was for the CKP sensor high to low res problem, which is the crankshaft sensor, it means there is a correlation problem between your crank sensor, there is a high res 24x(crank) and a low res 3x(ICM) and they have to equal 8 with the pulses they send to the PCM...so i would look at the ICm first, the flow chart says either look at the wiring and make sure it is ok and that there is no arcing, also look at the spark plug wires and make sure they are not laying on any wires also, and if those are ok and the connections are good, then it is almost 100% your ICM...i have one if you need it, but i have to test it first to make sure it is ok...its been sitting a while

02GAGTinprogres
03-07-2007, 12:03 PM
my email is tworz5@mizzou.edu, and thanks alot for the info. so far i have replaced the : cam position sensor, IAT sensor, TPS Sensor, Crank Position sensor, and the fuel filter. my car has 100,000 miles on it so im not worried about spending the money to replace all those. BUT!... that didnt fix the problem. last night, before reading your post, i was tracing all the wires from my remote starter/alarm. where audio express tapped onto the tach wire from the harness by the coil packs they used a t connect and it finally broke that purple wire. so i crimped it back together and everything is fine now. only problem now is that the shifts are still soft. will putting the resistor override back in my IAT sensor help boost line pressure? also could the soft shifts be becuase i had to do a PCM reset? thanks for your help.

gectek
03-07-2007, 12:33 PM
well there is a certain relearn time for everything, so that may be it, but i think ur tranny is just prob going out, all of them do, and ill get u that sheet in a few mins.

02GAGTinprogres
03-09-2007, 11:38 AM
my shifts are firm again, i had my friend with the transmission shop drive my car again and he said it was fine. i think it just took a while for my computer to realize that i am actually using an IAT sensor now instead of just the 3.3k resistor in the harness. also, since i replaced all of that my car makes a slight wine noise that varies with rpm...could it be related to a new sensor ?

gectek
03-09-2007, 11:45 AM
sometimes a small high pitched noise can be heard, but that is usually from either some blockage in the spacer plate, or some type of internal blockage or leaking, but this can also be a product of TB porosity, there is a tsb out about it. it just depends on where it is comming from

02GAGTinprogres
03-09-2007, 11:48 AM
it just started when i replaced the crank sensor...how can i check where its coming from?

gectek
03-09-2007, 11:50 AM
a stethescope will work good. good way to tell if it is internal engine, where at from the engine. that kind of stuff. it may be a vacuum leak as well...just a few thoughts

02RamAir
03-11-2007, 08:34 PM
My '02 GAGT shifts great when it is cold and gets progressively worse as the engine/tranny warm up. Once everything is warm if you floor it, when if shifts from 1st to 2nd at redline, it takes probably 2 seconds to actually go from 1st to 2nd. It literally sounds like a stick shift that somebody is learning to drive, it cannot be right. It actually shakes the car. The dealer won't do anything until it throws a code or SES light. Will this problem ever set a code or light how do I get someone to diagnose it and fix it.

gectek
03-11-2007, 08:54 PM
sounds like seals internally, i had a combo of this, bad trans mounts and worn clutches, so i had to overhaul it

02RamAir
03-12-2007, 08:10 AM
could it be the Transmission Fluid Pressure Switch?

02RamAir
03-15-2007, 06:24 PM
I took the car to a dealer by my school (not the one I bought the vehicle @ they didn't want to diagnose it) and since the car is under a warranty they are going to put a whole new rebuilt tranny in the car. The warranty company just wants to put a new trans in it rather than have the dealer take it apart and try to find out what is wrong with it, so i still don't know what was wrong but its getting fixed:D .

cardude007617
03-15-2007, 07:00 PM
wow lucky

Big Hood GT
03-19-2007, 09:40 PM
Hey GECTEK, just thought I'd update ya a bit, I haven't forgot about your offer, and I do appreciate you sending the build sheet. Here is the current status of the car, I did a tuneup on the car, plugs, wires, fuel filter, air filter, and flushed some of the nastiest stuff I've ever seen out of the throttle body. All symtoms have disappeared except when in drive and you nail it and the shift from 1st to 2nd is still slower than it should be, BUT it is better than before. If I shift it manually from L1 to L2 it bangs like it is supposed to. I've got my speedshop buddy analyzing data from his laptop that was connected during the test drive, currently we are leaning towards the TCC.....Thoughts???

gectek
03-19-2007, 11:21 PM
nope not the TCC, it doesnt apply in 1st or 2nd. u did say that it was just when the trans gets hot right, well i still believe that u may have a leaking seal or maybe some burned clutches that are applying better when the fluid is more directed to the 1st and 2nd apply passages by the manual valve position. i have seen the same thing also on mine when i had a lip seal that was a little damaged and the input clutches were fried, not so much 2nd but the ones in the input drum. alot of time if the 2nd clutch steels have hot spots on them they tend to not grip so hard when the fluid and internals are warmer...but if you have that, then u are in need of an overhaul anyway. i think that is the prob in the first place. you can mess with the pressures some but in the end there is 1 more thing that GM addressed in another upgrade to the trans. it is one of the bores in the valve body is taken out to better make use of the valve body and to take one of the crossdrilled valves and replacing it with a solid valve. you can get the upgrade kit for about $50 or so with the updated valve and better gasket and spacer plate, or you can get the entire valve body brand new with the upgrades for about $350...it almost eliminates that problem, but since it has gone on long enough you prob have more problems than that