Boss Lady

I've read several posts on the Forum and agree that the best SOP modification you can do for the money is to go with a lower gear ratio. I'm seriously considering changing the 2.59 stock gears to 3.54 in my 1993 with an Automatic Transmission. The thick Ring & Pinion seem to be readily available. Can anyone recommend a couple of brands to go with? Also, I wouldn't mind finding a newly rebuilt unit that I could swap out, so any contacts for going this route would be greatly appreciated. The few places I've called like Jasper don't offer the Dana 36. Several people have told me to be careful in my choice, because so many USA Manufacturers are now using foreign cheap metal in their gears. Thanks!

WVZR-1

Have you checked the RPO code to be sure you have 2.59's or you're just assuming because you have an A4 transmission? If you actually had maybe the 3.07 it would make a tremendous difference in your choices. Not doubting your request BUT it would create a few possibilities for you.

GM1, GU2 and G44 are the '93 possibilities with an A4.

Boss Lady

Yes I confirmed the information on the label under the center console. It shows GM1, which as you know is the 2.59 gear. Unlucky me! Like I mentioned above, I've read numerous posts on this subject but short of going through Eckler's or the like I can't find a rebuilt Dana 36 that I would know had quality parts in it.

WVZR-1

I'd post a WTB in the parts section and see what surfaced. You could get fortunate and someone has one and the gear ratio hasn't worked out. Ideally you would like too find one still in the car and close to you so you could maybe drive it to check for noises etc.

I don't know that there would be a preferred vendor presently for the D36 ratios. Richmond should still be a US manufactured unit and you could call them to confirm. They might be my first choice if I were looking to buy BUT I'd first try to find one that's built and in the car maybe. That would enable you to sell maybe your 2.59 as an assembled unit.

I have D36 housings but no differential/carrier presently to offer but if you wanted to build one it would be a start.

blackozvet

Summit sell the gear sets for Dana 36,
http://www.summitracing.com/int/sear...a%2036%20gears

remember to check description , some gears fit #2 carriers (being original gear sets starting in #2.xx) some fit #3 carriers.

Then you need installation kit containing all bearings, seals, gaskets etc,
so gears at $330 to $355, installation kit at $100 to $150, thats $500, plus someone who knows what their doing to install into pumpkin , your heading towards $700 to $900,

Its probably easier to buy a 3.54 pumpkin and swap out the 2.59 pumpkin, unless you want to make sure your diff is fresh and built as you want it ?

jispr

My 3:73 feels like I have twice the horsepower and 1/4 the gas mileage. Went back to 2:59 2 years ago and saved a lot of money.
Bought 2 pumpkins off Ebay if you trust the seller

Boss Lady

It's my understanding that I need the thick set of gears that some manufacturer's designate with a "T" at the end of the description. Today I found 2 shops that will do the swap. One will not do it installed on the car and they quoted me $865.00. The other shop I found gives a 12 month / 12,000 mile warranty and they'll take the car with the differential still installed, but the price seemed high. Labor was 10.2 hours at about $950.00 + parts. I think I can get the Yukon Gear for around $400.00 and the Installation Kit for around $200.00. I had no idea that the labor would be so much! I thinks Eckler's gets about $1,295.00 for the complete unit. I guess with hassling with the core return and labor, $1,550.00 from a local shop with a warranty is reasonable after all.

Boss Lady

Since I only put about 4,000 miles a year on my Corvette, I'm not overly concerned with gas mileage. However, I would have expected a slight decrease of maybe 20% or so, but 75%? WOW!

blackozvet

its the labor that's the killer !!
its amazing how a $350 set of gears can end up costing $1300

better off buying a 3.54 pumpkin for about $800 (or less maybe) and swapping it out yourself if you can.

vl5150

My 1990 came with a 3:33 D44, but I think a 3:45 was in the ZR-1 and earlier L98 M/T's What about something like that? Get your gears and then a cool mod at the same time. Just bolt in and go?

Heck, even if you find a 3:33, that's a huge jump from where you're at and splits the difference between your current gear and the 3:73.

I have a 6 speed and the 3:33 feels just right to me. 5th gear (.75) moves along at 2400 on the highway and can still get about 22-24 MPG. It will pull hard without downshifting.

jispr

I could almost watch the gas guage move. And you will have to replace both speedo gears if you want it to read correctly. I think I paid $250 - $300 on Ebay and both were in good condition. The latest 2:59 was almost new. Beats the $1300.00 The swap is straight forward, time consuming but easy to do IF you are handy with tools

Boss Lady

In regards to the speedo gears, I was told that the 1993 had a sensor that eliminated the need for changing anything for the speedometer to read correctly. I'm not 100% sure of this so can anyone confirm? The person that told me this said it was a 4 Pulse Sensor that first came out on either the 1992 or 1993 models. As for finding a differential on Ebay, I would be concerned of its condition.

WVZR-1

Your '93 still uses a mechanical speedometer drive/driven gear through a VSS for calibration. You will need both drive and driven if you do the 3.54 ratio or greater.

I mentioned the WTB in the parts section. If you don't post one you'll never know what's available or where. If you're serious that's where I'd start. It's very possible that there's even a new gear package available there also. Someone bought and maybe changed their mind or maybe money just got tight.

blackozvet

c409 had a 3.54 D44 rear end and wanted $800 for the pumpkin, looks like he sold it now,
so maybe put a wanted ad in and see what people have got