Thread: parts interchangibilty between a 1999 and a 2004 comp g

99 tranny and comp g tranny are totally different...comp g has paddle shifters. exhaust is all the same

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.

Clearance for headers is a little different but it will work with some elbow grease

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.

I didn't know the torque converter was different. What is different about them?

Originally Posted by t24moore

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.

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.

If you have headers, those will swap over.

The catback might be different.

If you planned on putting the 3.4 on it, I'd advise against it.

think it said in the brake thread rotors and calipers are swappable

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.

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.

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.