Thread: Want to get a Grand Pix GXP. ( Need opionions)

Hey guys, Ok ive got a list of cars that ive narrowed down to that i ll mention later on a differ thread for which ones is good. (I have done lots of research). But for now im stuck on one thing and that thing is should i get the GP GXP over the GTP? ive search for cars within 200miles of my location and i have found only one GTP that is in ok condition and only 5 total which is like beat to hell and high mileage. Also looked up the Impala and Buick regal and the Monte Carlo and still no dice. Been look for a 1999 or higher but nothing, The only car i found a lot of in my area is a few Grand Prix GXPs. 2 GXPs with 40-60k miles on it between 11-13.5k, we might be able to get a car in the next few months and my family misses the GP we used to have so i want to be able to get something like the GTP but instead now i want to get the GXP. OR the Impala SS sine i found like 3-5 of them too, but i have done lots of research and there are these 3 things that are stopping me from getting it and i wanted to know should these stop me from getting it and can these problems be fixed. well here it goes:

1. The Transmission - I've heard countless times that the tranny is weak as crap and that later i will need another one for like 3k which is a lot. I have also heard on the LS1 Tech forums that you can get a Transmission coolers that will help that out. I want to know that with only a CAI, and maybe either Exhaust or headers will the GP be ok for a DD and the tranny wont die on me also along if i install a Tranny cooler? Will those coolers help and how expensive are they and how hard to install?

2. The Different Tires - OK so i know for a fact that the front tires are i think 18x8 and the back are 18x7, ive seen a few forums and i think one on this forum that you can put 18x8 WHEELS all the way around and be safe to drive and will not change anything on performance or damaged anything on the car ( Also so a pic of some one GP doing that and the way the GP just sits there in that stance with those wheels it looks so so sick from the back). Is that possible or If not this what can i do? i just would hate to waste money ever time down the road to buy new tires for it since i wont be able to rotate them.

3. The cost of Owning the GXP - Ok and finally overall how expensive is it to have the GXP over the GTP or even the base GP? The gas seems to be good sinc ei could get like a combined 19-22 MPG since ill be going on the streets and the freeway. But other things like oil changes, how expensive will it be for this V8, the brakes, tires and if anything brakes down is it more expensive? Lastly what are the problems with this 5.3 V8 that could and might go wrong down the road, stuff like from the 3.8 3800 base GP the problems were like cheap coolant elbows, bad water pumps, LIM gaskets go bad, ETC?

I want to say Thank you in Advance this site had helped me out a lot when i had the base GP and i hope you guys can help me try to get the GXP GP or stay with the GTP. Also if both cars are fine which car should i choose over the other GTP or GXP? VERY IMPORTANT THIS CAR IS GOING TO BE A DD, and only mods ill get is like Intake and Exhaust That's why im stuck on getting a GXP. First i wanted the GTO but has to be a 4 door. Thank you guys again.

1. The trans is the same in reality, the case is just different, it can handle the power. Its just your foot that kills them. A transcooler on a GXP is a must IMO, they are a few write ups around that you can view. Ls1 tech has alot of info on the LS4 motor. A new fully rebuilt stock trans from TEP is like 1500 bucks, pretty dam good deal to me.

2. Yes the the rim size is different. 18x8 front and 18x7 rear. You can either buy 2 more of either front or back, or just buy 245/45/18 tires so you can rotate them like a normal car.

3. Cost is roughly the same. The LS4 motor doesnt have many common issues. Some burn oil with the DoD system, some can have a water pump leak (normal for the v8 trucks) and they take 6 quarts of oil on oil changes. So the cost is not that bad.

Thanks for the he quick answer, sorry if its too much reading i hate that i wrote A LOT, but im just noob on the GXP GP's. So is normal driving a car ok and from time to time putting the foot down to WOT ok for the trans and how much is the trans cooler? ( When i mean time to time i mean like one day ill do WOT racing some ricer or something and some days the highest will be half throttle. Oh and yes noob again what is TEP and DOD?

For the tires is it ok to run them for the first year and then get tires later on or the rims the ones you said 245/45/18? BTW Will the tires be expensive for this car or just as much as any other regular car or GP?

Well that a relief sort of to know that it wont be very expensive to maintain, also 6 quarts of oil is not bad since our SUV currently has 6 quarts in its 4.7 engine. One more thing hows the reliability on the GXP, great/good if care for it and not drive it around WOT all day like a dang race kar driver? Thanks again for the answers and more Opinions would be greatly appreciated especially from other GXP owners. Also on the Impala SS whats the differ on that VS the GXP? Ive heard the tires on them are the same all the way around, should i get that instead and do the two mods and the tranny cooler?
Thanks again

Triple edge performance. They build them.

DoD is Displacement on Demand. It shuts down 4 cylinder at crusing speeds to save fuel. During this, oil can seep past the rings on the cylinders that arent being used and thats where the oil usage comes into play.

The way you drive is nomral to me, beat on it from time to time but otherwise just a daily. A trans cooler is 50-100?? Check on LS1Tech for the most popular brand or even find what others use on here.

You wont have any issue running the tires the way they, because its like that from the factory. I am just saying when the times comes for new rubber, you can buy 245/45/18's so you can rotate them like normal. Tire prices depend on what tire you run and where you live. Could be anywhere from 100-200 a tire, brand/type of tire make the prices vary.

If it helps I love my gxp. Modding is expensive but I haven't had any major problems out of mine. For the tranny if u ever need one TEP quoted me 1800 approximately to rebuild mine. And that was if I send them mine and they use my original core for the rebuild. The tranny cooler is very easy to install in them to. But it seems to be a hit or a miss weather urs burns oil cause I've been lucky and it doesn't. I sometimes wish I had a gtp to do modding on but then again I love the interior of the gxp. Very cozy and nice to ride in.

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Hey thanks marines542 every comment/opinion from other owners helps me a lot and thanks ill check it out at TEP if i ever need it, Hopefully i dont ever or for a long long long time.

So pretty much what your are saying is that from time to time i beat on the trans is ok and wont hurt the trans like if i beat on it contentiously? Also that DoD seems to be a pretty cool since i use cruise control as much as i can on Freeways doing like 70-75mph so i should get some good MPG like at least 20. But ya the trans should be fine like that right? The trans cooler i will get possibly a month after i get the car hopefully. Ill also try joining the LS1 Tech forum to find out more info when i get it.

Hey also your saying that i have to change just the tire/rubber to 245/45/18's OR am i changing the whole Wheel/Rim to that same size, Or will the stock Wheel/Rim be ok? Pretty much after that change to the tire and putting on the Trans cooler the GXP shoud be a normal DD right, with a Badass V8?

Thanks again for the help FiveFingerDeathPunch. Any other Opinions from other owners i appreciate it too, the more the better and the more i will want the car too? Thanks

The stock sizes are 255/40 and 225/50 I think. Even though the rims are 1in different in width you can still put the same size tire on all 4 rims. Thats what many people run the 245/45's to keep it the same and have a better option for tires.

another thing too if u read u can have the DOD disabled. alot of people find no different for city milege becuase u barely have enough road in the city to have it kick in. thus eliminating the burning oil part. a cheap easy way for a tranny cooler- i did this myself- go to a junk yard. find a honda look on the rad they have an oil cooler. take it off and clean it out well. i paid 5 bucks for mine at junk yard lol.. one other thing for the gxp is check with TEP or transgo and get a shift kit. it helps keep the gxp from making a sloppy shift. it is also very simple but drop the transmission pan at least 2 times a year and they have a magnet in them but go to parts store and buy 2 more there like 5 bucks.

If you are just wanting a DD and have no desire to mod then GXP. If you feel you may mod then you would be better off with the GTP.

Originally Posted by txslow6

If you are just wanting a DD and have no desire to mod then GXP. If you feel you may mod then you would be better off with the GTP.

^^^^^ what he said. I wish I had a gtp sometimes just to mod

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@FiveFingerDeathPunch - So the stock rims are ok to install 245/45's tires all the way around to make it "Normal" tires to do rotations on and run that well for the rest of the cars life right? If yes than that completely Eliminates me worrying about the tires.

Also i hear about the Impala as i was doing some more research and i heard that the Impala SS has the same tires all the way around, also the brakes are regular brakes whereas on the GXP it ha drilled rotors that eat at brake pads. Is that true? Also should i look for the Impala first instead of the GXP, the SS is i think the same isn't it but with the same tires, better brakes, and just a differ name and interior? Also in differ sites ive heard that the GXP has tranny problems and that its not a reliable car, is that true or is it reliable. In some other sites ive heard that the LS4 engine in the GXP is a solid and reliable engine and a good car overall. So ive read mixed reviews and want to know your guys opinion and if the SS Impala is better than the GXP or visa versa.

Hey thanks joshv ill keep that in mind since junkyards around here has lots of crappy Honda's and Acuras, and i think if the DoD does no help at all i may just get it disable like you said. Also is the Shift kit a must or optional in your guys opinions if the only mod i will do is the CAI for like the first year i have the car?

Marines542 - ill keep that in mine i think i may, if i get the car, just change the plugs and wires say like 10-20k miles later. ill just run the stock plugs for lil bit then change em later so that its worth the money.

You guys answered a lot more than i thought of asking, a big Thanks to all of ya.


EDIT: Forgot to mention, the first car i will look up to buy if there is any good ones left is the GTP/ S/C GT GP 04+ or the Impala SS with the S/C 3800. Then if i cant find any for a good price and milage then ill look into the GXP or SS.

Originally Posted by marines542

yes you can change to the same size tire all around and alot of people do it. i have changed my brakes about 4000 miles ago and they do not eat pads...dunno where you heard that one from. the shift kit isnt a must but it will help extend the life of the tranny. it seems to shift way better with one in. a buddy of mine has an impala ss and everthing is exactly the same except interior and personally i love the gxp interior way better. as for the engine being reliable...it is very from what all ive read. its the stock transmission that isnt. and the impalas have the same transmission

How long did your brakes last and what kind did you use, and you do any hard braking? The only hard braking i do is just normal stuff like when the light hits red at the wrong time or when some slow ass idiot in front of me brakes so fast and hard way before getting to the light or for no reason at all.

I guess the tires should not bother me at all then, also how much are those shift kits and are they easy to put on? Mind you i only have regular tools like a few wrenches, pliers etc, no jack or anything but soon i will. Hopefully

There is some good information posted in this thread about what to expect and what to do if you go the GXP route.

If you are just wanting a DD and have no desire to mod then GXP. If you feel you may mod then you would be better off with the GTP.

I also agree with this statement. Although there are some mods that can be done on the GXP that will net you a little more power.

Ya your right The Guz if i ever need more help this site can give it, and same to you marine there are some mods i did find but they are expensive. The only mods i will do with the GXP is going to be a Air intake which ill custom make, and either a full Exhaust or Headers W/down-pipe (Which ever gives me the most for the buck), and MAYBE a tune. If those mods are tooo much for the tranny and if the tranny will die faster with all three and ill just get the intake. Also i will get the Shift kit, you guys know if they are expensive to have a mechanic put on or no? Thats if i dont put it on but is that shift kit like a simple bolt on, like take out the old and replace with new straight bolt on?

You guys helped me a lot and i think im on the right track on getting the GXP. But also if The impala SS is the exact same but differ interior to the GXP (I think the GXPs looks better than the SS), then that should be a good AlT if i cant find the GXP right? Also nobody answered: does the tires on the impala already have the same tires all the way around whereas the GXP does not?

I know im jumping the gun here but i forgot to mention i kept the old Air Box from our previous GP Base that we had to trade in, is that box the same as he one in the GXP/SS? Cause i wanted to take that air box from the car out and keep it and put that old one from the other GP on there but cutting off the top and back of the box and bolting on a Spectre or K&N cone Filter on there to make my Custiom CAI. That way if something goes wrong i still have the original Air Box to put back on. Can i do that?

BTW when it comes time to go shop for my car i will look for these cars first before the GXP in this order, You guys thing this is a good order to search for and if i can find the first one then just move on to the next one to find:

1. 04+ Grand Prix GTP/GT S/C Or Comp G
2. 04+ Impala SS S/C
3. Grand Prix GXP
4. Impala SS V8

Thank you all again for the help, and i hope to soon get one of those cars soon.