I want to know what is involved with converting my 323 posi to 373? Bear with me... I'm 17 and am still building my knoledge but have never had experience with the diff. other than changing the gear oil. Anway the other day while driving home my ring and piston gears chewed themselves to hell and need to be replaced. What is required to convert my diff to 373 because I am eventually building a 383 and dropping in a t-56 in the next few years and thought I may aswell upgrade my drivetrain because it will need it anyway. Can i put 373 gears in or do i need to buy a whole new diff. Any help would be appreciated, thanks.

 

i believe the carrier is fine, it would just be a gear swap and new bearings while its apart. Setting up the gears in critical, if you dont have the proper tools or know-how, have somebody else do it, or you'll trash the new gears real fast.

what rear? i assume its a 10 bolt?

 

Correct

 

do you think converting to 373 would be a good choice?

 

If you have to buy new ring and pinion anyway I would. Is this a daily driver, or a weekender only? Its going to get severely worse gas mileage with 3.73s, but if its not a DD then who cares? You can use the same carrier for all 3 searies gears. You can do 4.11s in the same carrier too if you wanted to. If it is a DD then 3.42 gears are a nice alternative.

You will need to recalibrate your speedo/odo if you want it to be accurate.

 

it is a dd right now... its a working project but I'm hoping to build it up over the next few years and than have it stored and only used once in a while to rip around town and take to the strip every now and than. The gas mileage would be a bit of an issue due to the fact that I don't have a lot of money. Like i said the ultimate goal is to swap the 305 with a 383 and a t-56 eventually. I just want my rear end to be able to handle the torque without having this same thing happening again.

 

Get higher quality gears. The ratio doesn't mean they are any stronger. If you want to get the same mpg you need the same ratio.

You do know what the different numbers mean right?

 

If I'm not mistaken, its the ratio of how much the axle turns to each turn of the drive shaft right? 3.73, the amount of times the axle spins to 1 spin of the drive shaft. So thinking about this the more teeth you have on the ring gear the more the axle will spin? Is that right?

 

I've been looking on summit the prices for kits are really good... but they don't have 323 gears. Tring to deside wheather to just buy the 373 or go the same for better mpg.

 

Someone correct me if i'm wrong here, but I believe that 3.23 gearing means that for every revolution of the drive shaft the wheels spin 3.23 times. 3.73 would get you .5 more tire revolutions per axle spin. Like I said earlier a 3.42 will bump your performance up a bit with minimal impact to your gas mileage.

With any gear change you will need to change your speedo gear or you will not be sure how fast you are going, or how many miles you are putting on your car.

https://www.thirdgen.org/gears
That link is a bit complicated to understand but its solid data.

 

Krik I think you have your theory backwards. 3:23 gears would mean that for every one complete revolution of the tires, the driveshaft will spin 3.23 revolutions. The way you were thinking would make it a super huge overdrive.

 

Oh yeah, what he said ^^

I knew that...no really...I promise

 

Hey, you lie to your friends, and Ill lie to mine, but lets not lie to each other.

 

Hi magnum_mcneil,
Obviously this is your choice but for future reference and to help us help you its easier if we know what your working with.If you go to "Edit Details" and scroll down about half way you will see,
car =
engine =
transmission =
axle/gears =
If you fill those in it really helps.
Of course again that's your choice.
Ron
PS. If you have plans to build a 383 and drop in a t-56 and are taking it to the track many here on this site will tell you not to wast your time beefing up a 10 bolt and to go with a stronger differential. But if you are like me and will only see the track rarely and will be using street tires. I say go for it. That being said,the 10 bolt can only benefit from using a support cover so you may consider one of these,and here's why = The Ultimate heat-treated aluminum support covers strengthen the rear housing from case distortion, preventing increased side bearing clearance and ring gear deflection. LPW's exclusive adjustable grade 8 load bolts prevent the bearing main caps from movement and possible breakage. Maintaining proper pinion depth & gear backlash results in maximum gear life and performance.
Here's their Link = http://www.lpwracing.com/p_capcovers.asp And if you really want to add some more strength to that cover there's this.=
http://www.lpwracing.com/p_axletubebrace.asp I have the cover but thought the tube braces were a little over-kill for now. But can be added at a later date.Any way here's what I did with mine. =
My 10 bolt upgrade including a Eaton 28 spline posi, new 28 spline axles ,3.42 ring and pinion and LPW Ultimate cover.

New 28 spline axles, master bearing kit, axle bearings and seals, and labor including 3.42 ring and pinion cost me $700.00. Then $535.00 for a 28 spline Eaton Posi. and $169.00 for a LPW Ultimate support cover..He gave me a unconditional 3 year warranty. Total = $1,404.00.

 

ronusmcmma-You spent how much on a 10 bolt? For a few hundred more you could of had a nice 9".

 

Yes , I guess that's true. At the time I was hoping I had the 28 spline axles.I read here on this site that the "89" Camaro could have ether one. Mine turned out to be 26 spline and I wanted the 28 spline Eaton posi. The axles were $250.00.The LPW cover cost me $169.00. Things just kept adding up. Thats were it went over my original plans.I was hoping to get it done for $1,000.00. The "Rear End" shop owner gave me a unconditional 3 year warranty. Said if I can break it he will replace it. I guess I couldn't ask for more than that.Am I happy with my set up. Yes. The Eaton posi. and 3.42 gears are a night and day difference from the one wheel peel and 2.73 .It has a nice "seat of your pants" feel to it now . You can feel it pushing your body and head in to the seats . Got to love that.

 

Hey do you guys know what ratios the fourth gen rears have stock? I want to swap out my weak 2:73 for at LEAST a 3:42! I was goin to definitely go with 3:73 but I want a happy medium and keep gas mileage decent.

 

Compared to rebuilding a 700r4, how hard is it to change the ring and pinion?

Just curious, maybe I can do it myself

 

lol this was a while back now forgot I posted this. I ended up buying the stronger borg warner 9 bolt for $300 off a guy. Its the 3-seriers with 3.23 gears. Disc brakes rather than the drums on my 10 bolt. Now i'll have to sand blast it, piant er up, change the gear oil and replace the cover with an aluminum one and more than likely get new rotors and pads. That should be able to hold up to the build this summer. Thanks everyone for the advice