imgn tht

My 2004 automatic is a basic bolt-ons car (cai, catted lt's, exhaust, ls6 intake) and not looking to go much crazier. *Maybe* a small cam down the road.

I'm thinking about changing the gears from the existing 2.73's to a 3.42 setup. My current diff is a single rib. I found a single rib 3.42 for $400 locally and strongly considering it.

Given my current mods/power and a possible cam and higher stall converter, will the single rib be good enough, or do I really need to seek out a 3-rib?

Rob 02

That is going to open a can of worms.
I would say that it is good enough.
The 3 rib came out later, when the Z06 had shot-peened gears which makes them a little harder to find and typically cost more.

imgn tht

In what way...because of mechanical issues, or because of opinions on the forum?

Rob 02

There are those that will say that the housing is not the weakest point and that the 3 rib is over rated for an application like this.
I personally don't know the difference in strength.
I would think that the shafts are the weakest point then the gears and clutch packs. If the internals blows through the case then it doesn't matter which case you have.

It would be hard to find a later Z06 diff at that price.

tbrowne

The 3.42's are a good price and they will give you better performance. I don't see how you could lose on the swap - go for it!

imgn tht

That's what I'm thinking too. I may have to be in that area to fix what I think is a front pump seal leak. Trying to plan ahead. This rear supposedly has 2000 miles on it, but the seller doesn't know more than that. So I'm hesistant on the unknown internal condition. Are they expensive to rebuild?

Rob 02

There are very few companies I would trust to rebuild one due to the complexity. I have the process somewhere and to do it right requires some special tools. So yes it is fairly expensive to rebuild.
You can't beat RPM for their quality but the price is a little over $2k +core.
http://www.rpmtransmissions.com/page8.html

imgn tht

Yikes...maybe rebuild was the wrong choice. Maybe what I mean recondition. I read before about belleville washers and new seals, that sort of stuff.

Rob 02

Seals are cheap. Pop the old ones out and put new ones in.

Rob 02

When you make the swap you will need a tune. A mail order tune should be fine. I sent my PCM to ECS and really like it. I currently have 3.15 gears but am considering going to 3.42 even though that isn't a big jump for mine.

It should really wake yours up. If you are that deep you may want to consider a higher stall converter. Here is an interesting thread. It is from a while back before a lot of the tuning was figured out. With the tune and gears it should feel like a different car.
https://www.corvetteforum.com/forums...-da-floor.html

imgn tht

Aware of the tune and planning higher stall converter if I do dig in this deep. Much of this is dependent on what the Corvette Shop tells me later this week what they plan to charge to fix my trans leak. If they tell me they have to get in that deep, then converter and gears are a no brainer. I just don't want expensive surprises because I didn't ask questions first.

DOUG @ ECS

I suggest you use one of our trans braces when you install the 3.42's, that would eliminate the issue of the single rib case.

http://www.eastcoastsupercharging.co...ategory_id=152

Rob 02

^+1 I'm considering one too.

I can't say enough good things about ECS. I had a minor issue with my tune and Doug took care of it. Their customer service is excellent.

STL Mike

I have a C6 diff for sale if it'll work out for you, I'm negotiable on the price.

https://www.corvetteforum.com/forums...2-56-gear.html

imgn tht

Saw those, but a 2.56 would be worse than I already have. 3.42's are all that I am interested in.

Rob 02

All this talk about ribs is making me hungry.

STL Mike

Good time for a gear change. They will really wake the car up and if you're going to have to have the pcm reflashed anyway, you may as well do it right to optimize your setup. Something to think about...

Rob 02

Plus it is a C6 diff. It is a little tricky to get that to work in a C5. If the OP was going to rebuild one for lower gears he could just rebuild his existing diff.

I think there is some confusion here.

imgn tht

Every time I come across the ad two things come to mind. 1. Why is it posted in the C5 section, and 2. Who would want 2.56's? No offense meant to the seller, its just that for all my years on the forum my existing 2.73's are crapped on as the least desirable gear set for an automatic. So for all the labor and expense to make a gear change, I only want to go better a.k.a at least 3.42's.

imgn tht

Yes, good time for gear change, which is what the topic of my original post was about. Are you suggesting the 2.56 gear set will wake up the car?