• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

parts interchangibilty between a 1999 and a 2004 comp g

SgtMarshal

SgtMarshal

Active member
Im trying to find an article on what parts, if any, will swap over from a 1999 to a 2004 comp g. im mostly interested in the exhaust if it would be a direct fit or a close fit but im also curious if there are any other parts that would fit. also, is it possible to get the transmission out of a 1999 and have it rebuilt to match the performance characteristics of the comp g.
 


04+ cars need 04+ trans that matches the car it came out of.

Anything before that (97-03) can't work, internals are different and the way its controlled via the PCM aswell.
 
The internals on the 4T65E are the same I think in both 99 and 04+ and the engines blocks are the same as well. Only difference is in the PCM, torque converter and gear ratio.
 


t24moore said:
The internals on the 4T65E are the same I think in both 99 and 04+ and the engines blocks are the same as well. Only difference is in the PCM, torque converter and gear ratio.
Click to expand...

Internals are almost the same but still different.

Everything from 2003 and above has a differnet valve body, newer clutches etc etc, hard parts, and is controlled via the PCM different that than a 97-02.

Flex plates are different as well IIRC.

The motors are the same block, you'd have to swap your brackets and parts over to it to make it bolt right in, then if you kept the GEN V blower, you will have to research on how to make it work on the 97-03 cars. Headers are a must if you went that way, or you could swap your top end over and call it a day.
 
I probably should have said this in the beginning of the topic but I have a 1999 gtp and am considering getting an 04 comp g. In my 99 I have full exhaust and intake and am running a 3.4 with no knock . all I really would want to do is swap the exhaust.

The comp g has an upgraded suspension right?

Sent from my YP-G70 using Tapatalk 2
 
I have pems and a catless dp and I was going to do a 3.6 after the intake and exhaust are done

Sent from my YP-G70 using Tapatalk 2
 


Hopefully you have a scangauge of some sorts. The car may or may not take well to the pulley drop. IMO pems wont flow enough and you'll see KR and need the stock pulley or a custom tune.
 
Yeah pcm is diff , tb on genv diff , someone said gear ratio the same the comp has the 3.29 i would rather have that. Comp doesnt have performance suspension as far as i know. But struts and what not are different from 97 to 03 i have an 04 and kyb were different part#. You can make the comp suspension the same as the other years just need that years lca i belive.
 
I cant find anything anywhere supporting your claims of hardened parts, valve body changes, or clutches. GM hasnt changed the 4T65 as far as im aware when it comes to the w-body. Also looking on trannymans site there is no price difference when it comes to these transmissions. Now the Volvo 4t65 has a different valve body but not ours. The flex plate is only different due to the differences in torque converter sizes. But thats more of a NA block versus SC block thing rather than a year specific issue.
 
The 4T65-E was introduced to replace the 4T60-E in 1997. The 4T65-E included a larger 258 mm torque converter for some models and many other changes to improve reliability. It is able to handle vehicles up to 6500 lb (2948 kg) GVWR with up to 280 ft·lbf (380 N·m) of torque. A number of final drive ratios are available, with many distinct models. Starting in mid year 2000 models, all 4T65-E models received an upgraded valve body. Starting in 2003 the internal electronics were changed, hardened 4th gear shaft, ratcheting sprags for input and third gear were added.
Click to expand...

Found that.

So?

And in 2003 the valve body was changed again and the electronics, hence why the 03 is a year only transmission.

And 04+ cars have newer and better parts than the 97-03 cars, technology in them.
 


The comp G trans is not interchangable with any other trans. I forget exactly what the compatability issue was, but there is one.

Also switching gear ratios requires a tune to compensate for the change.
 
I forgot about the fancy tap shift, so youre correct that the valve body is different to compensate for that. But far as new and better parts.....thats debatable. I still think the series 2 L67 is the best engine. Also over the past 6 years we have never bricked a 97 PCM. And my axles are from my 97 GTP that wrecked with a ton of track passes on them. I just recently replaced one boot. I personally think the newer stuff is cheaper. Its been proven already that the L67 had stronger rods. Technology isnt always better on cars IMO.
 
Last edited:
You must log in or register to reply here.
Back
Top