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2005 GT tranny is going, i want to put a GTP engine and tranny into my car. possible?

winterstorm

winterstorm

New member
I have a 2005 GP GT and the transmission is going. I want to put a GTP engine and transmission into it instead of another GT. I know that Ill have to use the GTP computer. Is there anything else I would have to do? what years will work? Im going to be buying this stuff from a junk/parts yard if that makes a difference...looking for one that has around 30,000 miles on it.
 


Meh on the GTP trans, the gearing in your car is better.

The transmissions are the same...minus the HD Diff.

Just top swap it.
 
my transmission is going bad though thats what i need to swap out. my dad said just do the engine too so i wanna do the gtp engine. im guessing if i did a gt transmission with a gtp engine i would have to reprogram the computer system and i dont really want to go through that. so a gtp engine will work in a gt?...am i looking to get anything from 04-08 for years (will 07 and 08 work too)? what is the easiest thing to do in this situation that you recommend?
 
if your changing the engine and trans you will need to change the computer anyway. and for that computer (PCM) to work with your interior computer (BCM) the vins will need to match... this will require tuning anyway. so you might as well pic the engine and trans you want and have the pcm tuned to match. there are mail order vendors who will sell you a pcm or you can ask around and find someone local to tune your car.

I also agree with going with the non GTP trans. when i did my swap from the original 3.4L DOHC engine to a 3800 series engine i did this. i chose the regular 4t65e and also go the L36 and got a topswap kit. the non HD trans gives a gear ratio that allows faster acceleration and using the higher compression L36 will give me more power for the same boost level once i install the topswap.

from the sound of it all though... you are considering changing the engine for a more reliable one. in this case go with the L32 and call it a day. for mods it all depends on how fast you want it, but i would start with headers as now is the time if the engine will be out of the car. Now is also the time for a cam if your plans all for it in the future. but i just dont see getting a diff engine only to crack it all open to drop in a cam... might as well cam your existing engine and do a gen V topswap.
 
im not familiar with the top swap kit. im just looking to get a gtp engine from a parts yard and a tranny and slap it in there. if a top swap kit requires taking apart the engine i dont really have time for that cuz i need to minimize time spent doing this. will a gt tranny work with a gtp engine? if i did a mail order PCM would they send it to me tuned to my transmission specs and vin# or would i still have to go to someone to have that done?
 
mwinters29 said:
im not familiar with the top swap kit. im just looking to get a gtp engine from a parts yard and a tranny and slap it in there. if a top swap kit requires taking apart the engine i dont really have time for that cuz i need to minimize time spent doing this. will a gt tranny work with a gtp engine? if i did a mail order PCM would they send it to me tuned to my transmission specs and vin# or would i still have to go to someone to have that done?
Click to expand...

Well if you get a junker engine and don't do gaskets you're only wasting your own time. Same work involved on a top swap.

Sent from my Galaxy Nexus using Tapatalk 2
 


i just dont kno what a top swap entails. im getting the junker engine to save money cuz i dont have 4000 to spend on a new engine and tranny. and im doing this cuz my dad did the same to his 2000 grand prix gt except he just put the same engine in, not the gtp so i just wanna know if putting the gtp in with a gt tranny will work and how much a PCM is gunna cost me to get and get it tuned
 
bluegtp91 said:
Meh on the GTP trans, the gearing in your car is better.
The transmissions are the same...minus the HD Diff.
Click to expand...

Blue is close: The transmissions are close to the same, not the same. The differences in the transmissions are the differential, diff housing and the drive/driven gear sprockets. In an HD diff the sprockets are 33/37 with a 3.29 diff. This makes a 2.93 overall ratio. In a non-HD the sprockets are 35/35 with a 3.29 diff to make an overall ratio of 3.29.

acidcrashdburnd said:
Well if you get a junker engine and don't do gaskets you're only wasting your own time. Same work involved on a top swap.
Click to expand...

I disagree on this one. If the LIM gaskets are plastic, then they should be replaced with the newer aluminum ones. However on most of the years you are looking into, the gaskets are likely the aluminum ones. In addition, there would be no need to take off the heads for any reason. The amount of work is very different from LIM gaskets to top swap, based on the heads not having to come off.

My suggestion based on what you've said would be to get the engine, trans and passenger axle (it's different lengths based on the HD diff or GT diff, GT being a little longer) Drop it in, pick up a vendor pcm with the correct vin for your car and the GTP programming for the rest. Maybe have them do a basic tune on it for you while you are buying it anyhow.
 
is it necessary to get the passenger axle? if so how much am i looking at for one from a parts yard? and i see you are also from CT. im from bristol. do you kno of anywhere i can look for this stuff? i kno of some places. and also where would you get the pcm? could i just get it from the car i get the engine and trans from? ive been looking online and i only see the upgraded pcm that you arent supposed to use on your car that you drive on the roads, says for track use only haha
 
Wow, didn't realize you were Bristol.. We should get together sometime.

Chuck and Eddies in Southington, there's a place in Webster (I think it's called Webster as well) and a few other places around. Axle..I'd likely expect $20-30 at the most. anything more and you might as well buy a new one from Napa.

The PCM, You could grab the one from the yard, then have the vin etc changed up to meet the needs of the car. Since you have emissions to worry about, the vin must match in the pcm to the vin of the car. I've been there..dealt with that.
 
If you're looking at top-swapping the top-end, I'm local and have plenty of parts I could sell to you (GenV, LIM, etc)... plus, you have Bill who can install (if you need someone to do the work) :)
 


alright thanks guys! my dad and i can do the install, we did the engine and trans for his 2000 grand prix when he had it so we should be fine. its just the tuning that will be needed thats throwing us off a little bit cuz thats the one thing he doesnt know how to do haha. @intrigue98. im not sure if ill need any parts, im gunna see what i can get from a parts yard but if i need any ill let you know. thanks for the offer!
 
oh i just thought of this...i have heads up display in my car and i absolutely love it haha...will a different pcm have any affect on that cuz i dont kno if i could give that up haha
 
Not to thread jack, but bill. Addin the HUD you do t need the special glass? I was under the impression the gtps had a special windshield for the HUD. If that is not the case do you think I could put one in my monte? Is it just like wiring in the speedo and any other sensors?
 


good luck with the install. if you do have a little extra time while the engine is out you can do a top swap. which means taking a normally naturally aspirated 3800 and putting the supercharger on it. by doing it this way you will get more horsepower out of your engine.
 
so if i did do a top swap without putting the entire gtp engine in, how much money do you think i would be looking at if i got all the parts i needed from a parts yard?
 
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