# 2005 GTO Differential into 2004 GTO



## Littleguy (Jul 3, 2011)

Hi all, I need to replace the differential in my 2004 GTO and I am wondering if I can use the differential from a 2005 to replace it? The gear ratios seem to be the same, but I don't know if there are any differences that would stop me from doing it or if any modifications would need to be done. Also, how well will the 2005 differential hold up on a bolt-on car that is not launched or abused? Any better than the 2004 unit?

Thanks in advance for the help.


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## Falco21 (May 11, 2010)

Yes it will fit. The 05/06 differential will fit in the 04. Many have had that done. The only problem you are going to run into is the bolt pattern is different. In the 04, the bolt pattern from the drive shaft to the rear end is narrower. The best way of doing it would be to buy a one piece drive shaft. You could bolt that right up to the rear end with no problems what so ever.


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## Littleguy (Jul 3, 2011)

Is there any way to get it to work with the stock drive shaft?


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## danfigg (Sep 27, 2009)

*re*

probably using the 05 drive shaft should work or maybe the 05 yoke should work on the 04 drive shaft---------danfigg


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## GM4life (Mar 18, 2007)

Littleguy said:


> Hi all, I need to replace the differential in my 2004 GTO and I am wondering if I can use the differential from a 2005 to replace it? The gear ratios seem to be the same, but I don't know if there are any differences that would stop me from doing it or if any modifications would need to be done. Also, how well will the 2005 differential hold up on a bolt-on car that is not launched or abused? Any better than the 2004 unit?
> 
> Thanks in advance for the help.


Yes you can, the the 05+ diff is a little stronger being that it came from the AWD version in Aus. The pinion is bigger becuse the 05+ driveshaft was bigger and stronger. The halfshafts are stronger too.


Littleguy said:


> Is there any way to get it to work with the stock drive shaft?


You need to use the pinion from the 04 diff on the 05 diff to use the driveshaft.


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## Littleguy (Jul 3, 2011)

Thanks again for all the replies.

So, to make sure I got this straight, I am going to try and use the Pinion from my worn out 2004 diff and if it is damaged I will either have to get another 2004 pinion or a 2005 driveshaft. Correct?


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## danfigg (Sep 27, 2009)

*re*

Little guy I think the easiest way is to use the 05 Drive shaft. I looked at pictures and saw that the yoke side that goes in the tranny look simular its the end that goes to the diff that is different. I think you would have to seperate the 04 drive shaft and add the 05 shaft to the diff. But to go through all this you might as well just get a 05 or 06 drivshaft and that should do it I saw some on Ebay-danfigg


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## Littleguy (Jul 3, 2011)

Thanks Dan. I just ordered a 2005 complete 2-piece drive shaft, and the 2005 rear differential is on the way too. Are there any other parts that I will need?


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## Littleguy (Jul 3, 2011)

Also, the one I ordered does not have rubber couplers, anybody know where to buy them for a reasonable price? Or could I use the couplers from my old drive shaft?


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## GM4life (Mar 18, 2007)

Littleguy said:


> Also, the one I ordered does not have rubber couplers, anybody know where to buy them for a reasonable price? Or could I use the couplers from my old drive shaft?


Good luck trying to get them from GM if you can. You have to find them from someone that has removed their driveshaft. Check ebay or forums. From my understanding the rubber couplers on 05+ are also bigger than 04's because of the driveshaft is bigger. I had one for sale not that long ago but now its in storage. If you can't find some, like I said use the yoke from the 04 and use it on the 05 diff so you can still use the stock drivshaft or buy a good aftermarket 1 or 2 piece driveshaft.


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## Littleguy (Jul 3, 2011)

GM4life said:


> Good luck trying to get them from GM if you can. You have to find them from someone that has removed their driveshaft. Check ebay or forums. From my understanding the rubber couplers on 05+ are also bigger than 04's because of the driveshaft is bigger. I had one for sale not that long ago but now its in storage. If you can't find some, like I said use the yoke from the 04 and use it on the 05 diff so you can still use the stock drivshaft or buy a good aftermarket 1 or 2 piece driveshaft.


Thanks, I'm hoping that now between the 05 driveshaft and parts salvageable from my 04 differential I will be able to make it fit. I am planning to do a 1 piece driveshaft in the spring, but this problem came up at the last minute and I want to have it fixed quickly so I can take the car to Mid Ohio in 4 weeks.

Thanks everybody for the help, I'll be sure to update the thread on the install and what I end up doing.


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## Littleguy (Jul 3, 2011)

Update.....The 2005 parts were installed today and the car is completely, 100%, better. All of the clunk noises and general "loose" feel that were present on the car are gone. The shop ended up using the 2005 differential and my 2004 driveshaft (I know there were a couple of other parts they used, but I'm no expert). I'd like to thank the people in this thread for their awesome advice!


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## V8supercar (Sep 3, 2011)

Hey little guy got a question for you about your diff swap . Why the need for a complete diff swap ??? Why didn't you just get what ever was making the clunk sound fixed ??? Seems it would be alot cheaper and alot faster of a fix , than a complete diff swap . Sorry if this is a dumb ? but i'm a recent buyer of a 06 GTO and i hope if mine ever developed a clunk in the rearend i don't have to buy a whole diff . I can't imagine what ever is causing the problem you had would be more expensive to fix than what a new diff costs, plus installation.


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## Littleguy (Jul 3, 2011)

V8supercar said:


> Hey little guy got a question for you about your diff swap . Why the need for a complete diff swap ??? Why didn't you just get what ever was making the clunk sound fixed ??? Seems it would be alot cheaper and alot faster of a fix , than a complete diff swap . Sorry if this is a dumb ? but i'm a recent buyer of a 06 GTO and i hope if mine ever developed a clunk in the rearend i don't have to buy a whole diff . I can't imagine what ever is causing the problem you had would be more expensive to fix than what a new diff costs, plus installation.


Not a dumb question at all. I went for the entire diff. for a couple of reasons. First of all the Diff on the 2004, from what I read, is not as strong as the 2005-06 and I plan on doing more upgrades anyways. Second was because I got such a great price on the 2005 differential ($330 shipped), and when I put it side by side with my old one it is in much better condition. Finally, now that the old diff is just laying around I will be going through it to find what exactly was causing the clunking like you said, and I will keep it on the side to use as a basis to build up a diff if/when I decide to get a little more crazy with power (spray/turbo/SC). I hope this answers your question, and that you never get the dreaded "clunk" noise either, lol.


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## Cwarta (Oct 26, 2011)

How many miles do you guys have on your cars that they are this worn out?!?


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## Littleguy (Jul 3, 2011)

Cwarta said:


> How many miles do you guys have on your cars that they are this worn out?!?


I purchased mine with 41000 miles on it.


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