Thread: 2006 GXP Trans into 2004 Comp G: Possible?

OK, so I have a 2004 Comp G that I believe has lost the forward apply band. A local JY just got in a 2006 GXP, looks to be wrecked. Will the transmission from that vehicle work in my car with minimal modification? I can get the computer tuned for the 2.93 gear ratio since mine is 3.29.

As long as the GXP had tap-shift, it shouldn't be too big of an issue, IIRC the axles were different but you could always grab those as well.

The gear ratio will make it feel much slower, but it'll be driving again at least. Lol

Will not work, ever.

The GXP transmission case if for GXP onlys. The starter location on the bell hosuing is completely different and can't work on a 3800.

Ah... Forgot about the starter. My bad. Lol

The internals would still be worth pulling the trans, though... Right? ;D

yes it will work I had one in my comp G for a little while till it got the built trans from Triple Edge performance.
I gave Dave the GXP trans for a core when I picked it up

Well that settles it. Lol

I trust James.

With some time and elbow grease it can work. Hell im taking a rebuilt impala trans and swapping over my comp g internals and adding some harden parts for my turbo car.

Originally Posted by Turbocharged400sbc

yes it will work I had one in my comp G for a little while till it got the built trans from Triple Edge performance.
I gave Dave the GXP trans for a core when I picked it up

I am buying the trans on Saturday, so if you can share specifics on what I need to modify, I would really be in your debt. Thanks!!

I'm curious too, even trannyman dave has said the LS4 has a different case for the starter location.

I'm curious as well... This might be an extra option for some of us.

I'm really hoping it is a simple fix - we just got a GXP in at our LKQ and I can get the trans for $100. Otherwise I have a line on a known good Comp G trans for $150 but I have to drive 9 hours to get it.

I will tell you that the GXP starter boss without a starter attached easily cleared the zzp headers.
are starter mounts to the block below where the LS4 does you just end up with an opening right there... call it the broken flexplate inspection window for all I care.
there were no wiring issues or anything it was Plug and Play

So we can put it this way.

GXP to GT/GTP is okay to swap.

But GT/GTP to GXP is not okay because the starter position is totally different and the regular 4T65e case wouldn't work.

Originally Posted by Turbocharged400sbc

I will tell you that the GXP starter boss without a starter attached easily cleared the zzp headers.
are starter mounts to the block below where the LS4 does you just end up with an opening right there... call it the broken flexplate inspection window for all I care.
there were no wiring issues or anything it was Plug and Play

THANK YOU! Definitely grabbing it. Now that I know that, I get to start worrying about what issues I will have electrically and mechanically. Ugh. Maybe I will swap all the sensors from my current trans over since they all worked fine and no codes at all were thrown about the trans. Cheap insurance, I'd wager. Or I'll have the guy working on it test them if that's even possible.

Thanks everyone for the quick responses. Saved me some headache and a trip to NY!

to be clear....I have not tried oem manifolds/flanges, pacesetters have loose flanges that can be clocked, the zzp headers have nothing in that area as its a slip connection under the TB for their crossover pipe plumbing

but at most id say youd have to hit it with a grinder

Originally Posted by Turbocharged400sbc

to be clear....I have not tried oem manifolds/flanges, pacesetters have loose flanges that can be clocked, the zzp headers have nothing in that area as its a slip connection under the TB for their crossover pipe plumbing

but at most id say youd have to hit it with a grinder

If I had the extra money I'd totally convince my wife that I need headers now. XD

It doesn't fit with the ls4 starter on there

I just finished swapping in the 97 trans/engine (I yanked from my rusted out 97 5TP) into my new 04 compG during its demod (and cause the trans lost 3rd).

I used a jumper harness I made using the 97 trans/range switch harness wired to the "inline" 4t80e trans plug (trans side is on a pigtail outside the trans case on the 80e- makes the perfect trans side connector that plugs straight into the OE 4t65e trans connector)

sometimes I thank the heavens that GM is so well at using common parts bin stuff....

works great, I haven't programmed the PCM with a std non-TAPshift GTP file but it drove fine in D. I haven't tried to use tapshift with it, im still trying to make it my new DD General Purpose crap hauler (since my DD is always full of car parts/project parts) to replace my current 04 GTP clone

its almost sad that such a well optioned black/black CompG is gonna be treated like a beater....hell I was gonna **** around and put the gen3 blower on with a tb adaptor just to take it in for the recall and see if the techs noticed....

eventually ill fix 3rd (pretty sure its the sprag since I can get into 3rd on a 4-3 tapshift for a moment.) and swap the trans back in.

but for now the cG' original L32/XP engine is sitting next to its mate prepped and ready for the 442's new chassis.

while yanking the zzp headers and dropping in the PEM's equipped 97 motor I did notice that it looks like it would clear the LS4 trans case starter boss- sans ls4 starter.