I did a search on the 04/05 rear diff upgrade from Honda and this is what I found...

For an '00 through '03, one of the best options is to purchase an '04 diff housing and carrier. This would require a complete rebuild and makes the option of switching to a different gear set much more attractive.
The '04 diff housing (the front part that's painted black) has better oiling than the earlier models and has slightly more reinforcement. Honda determined that oiling had as much or more to do with diff failures than any of the other reported failures and accommodated this in the '04 diff.

Is this the only improvement to the rear? And is there a way to tell an 04/05 rear diff from an earlier 00/03 dif with out taking it apart? A tag with numbers or is it a different shape?

 

i've seen an 02 diff next to an 04 and it doesn't look any different to me....

 

according the posts I have seen, 04' diffs are upgraded to be more durable. I found one for my 00' at a parts recycler.

 

i think that the diff lockup rate is different also.

 

I am trying to avoid buying a "placebo rear end" thinking I have a newer better one when I just have the same old rear.

"The '04 diff housing (the front part that's painted black) has better oiling than the earlier models and has slightly more reinforcement". Does any one know what the
extra reinforcement Honda did? And dose the 04/05 rear except more than one liter of gear oil?

 

Does any one know what the extra reinforcement Honda did?
If they did, I sure could not see it. We had then side by side in late 03 (as so as they released the part), 01 OEM, 04 OEM and CompTech. Only the CompTech showed to be reinforced on the caps. There was a minor differance in the cap on the OEM 04, but that could simply be from the new casting mold.

Again these were our observations and not detailed analysis.

And dose the 04/05 rear except more than one liter of gear oil?
Maybe a litte more due to the fact that the lower oil passage to the pinion has increased in size. But other then that no.

 

Thank you, so is it a better rear????? or is it just assumed that it is?????

I'm guessing that it is just hype and there is no concrete proof that it is a better unit.

 

I have read here that the new rear diff is 15% stronger and that the end caps are "similar" to the Comptech re-inforcements. HOWEVER, no proof was provided so take this with a huge grain of salt.
The older diff takes less than 0.8 qts of fluid. I highly doubt that they made the new take over 1 qt. unless they moved the fill bolt up higher. Nevertheless, it is entirely possible to put 1qt. of fluid into the rear diff with an overfill. A few people, including myself, routinely overfill by 100cc for the added heat carrying capacity and greater lubricating volume.

 

If someone has a parts list with #'s the old and new could be compared.

 

I have a line on an 04 dif from a wreck with low miles for a good price. I want to build a better rear for the car and was hoping to start with a better unit to begin with.