Trying to pick up a 3.42 rear in place of my 2.73 rear

**Firebirdjones** · 12-08-2010, 02:30 PM

That's really the only advantage to swapping in a complete 10 bolt with a better gear,,,,having the ability to swap back in the original if something were to happen.
If you can find them for chump change then it's a worth while effort, and pick up an extra one too. But when they start getting around the $300-$400 range, I'd probably look into other alternatives.
Quite frankly if you plan to keep the car,,,I'd just do a 12 bolt and be done with it.

**allbaugh_04** · 12-08-2010, 06:38 PM

That's the thing...the car is worth what..7-8k at this point. I have a hard time putting forth that much money. Money isn't the issue, it's just doesn't seem smart on a car that's only worth this much.

**TLS_Addict** · 12-09-2010, 10:00 AM

Originally Posted by allbaugh_04

Well I got some thinking to do then. I'd think 3.42s would be a better upgrade, I'd just rather have a 4 channel and make no changes, if it breaks i can always swap my old one back in...quickly.

I might consider 3.23s, I think the 2.73s are hurting me though. I can't beat my roommate sometimes and I'd like to...Ryan if you are reading this

I'd like to beat him consistently and we have similar mods, but he has 3.73s and M/Ts...I got 2.73s and Nittos.

What are you running in the 1/4 mile right now?

My 2000 A4 with 2.73s ran 13.51@103.72. My car was 3,525 lbs without me in it (1/2 tank of gas) so add in my 220 lb ass and the car is at 3,735 lbs. My friends 02 T/A WS6 (he is on here) ran 13.39@106. He was 3,570 lbs and he is about 180 lbs so he is 3,750. He is rated at more hp and has the 3.23 rear. That to me says that we are "close" on power but that his gears are mostly what makes up the .12 seconds.

I would love to see the progression (everything else being equal) from 2.73, to 3.23, 3.42, and 3.73 gears.

Originally Posted by allbaugh_04

That's the thing...the car is worth what..7-8k at this point. I have a hard time putting forth that much money. Money isn't the issue, it's just doesn't seem smart on a car that's only worth this much.

**Firebirdjones** · 12-09-2010, 10:02 AM

Originally Posted by allbaugh_04

That's the thing...the car is worth what..7-8k at this point. I have a hard time putting forth that much money. Money isn't the issue, it's just doesn't seem smart on a car that's only worth this much.

Well that's just it. You have to decide whether you are keeping the car, in which case value doesn't matter. You'll have to look past that.

I have several cars with more money tied up in than I can sell them for. But it's a hobby, I enjoy the cars, don't plan to sell, so I pay no attention. I don't even bother to tally up receipts anymore for the last 15 years, it would get depressing

For instance, owned the chevelle since 87. 4 different engine combinations at several thousand $$$ a piece, 3 different transmissions, on the second rearend, one paint job, new seat covers, blah blah blah. And I'm thinking about another engine combo I'm going to do in the future already, because they are never fast enough. See what I mean??

**allbaugh_04** · 12-09-2010, 10:52 AM

Originally Posted by TLS_Addict

What are you running in the 1/4 mile right now?

My 2000 A4 with 2.73s ran 13.51@103.72. My car was 3,525 lbs without me in it (1/2 tank of gas) so add in my 220 lb ass and the car is at 3,735 lbs. My friends 02 T/A WS6 (he is on here) ran 13.39@106. He was 3,570 lbs and he is about 180 lbs so he is 3,750. He is rated at more hp and has the 3.23 rear. That to me says that we are "close" on power but that his gears are mostly what makes up the .12 seconds.

I would love to see the progression (everything else being equal) from 2.73, to 3.23, 3.42, and 3.73 gears.

IDK, i'd estimate high 11s, cuz that's what my roommate runs, but he has M/Ts. Just bench racing here. My car weighs 3400 and 3575 with me in it. If i could ever find traction I think 11s is reasonable.

Originally Posted by Firebirdjones

Well that's just it. You have to decide whether you are keeping the car, in which case value doesn't matter. You'll have to look past that.

I have several cars with more money tied up in than I can sell them for. But it's a hobby, I enjoy the cars, don't plan to sell, so I pay no attention. I don't even bother to tally up receipts anymore for the last 15 years, it would get depressing

For instance, owned the chevelle since 87. 4 different engine combinations at several thousand $$$ a piece, 3 different transmissions, on the second rearend, one paint job, new seat covers, blah blah blah. And I'm thinking about another engine combo I'm going to do in the future already, because they are never fast enough. See what I mean??

I don't plan on selling it, because it's not worth anything (only pay for insurance and registration) and sure modding an older car makes more sense, it's not made of plastic everywhere. I mean I take care of the car very well, but it's not gonna be in good shape forever. I just think 10 - 10bolts is cheaper than one 12-bolt. Considering a friend of mine has gone 10.5 in his 3.23 geared camaro with one.

**Firebirdjones** · 12-09-2010, 02:12 PM

Originally Posted by allbaugh_04

I don't plan on selling it, because it's not worth anything (only pay for insurance and registration) and sure modding an older car makes more sense, it's not made of plastic everywhere. I mean I take care of the car very well, but it's not gonna be in good shape forever. I just think 10 - 10bolts is cheaper than one 12-bolt. Considering a friend of mine has gone 10.5 in his 3.23 geared camaro with one.

I can understand. Don't really know how much racing you plan to do, but an auto with the 7.5 and very mild gears could last a while. I've seen alot of them in the 11's still running stock gears.

The more gear you put in these 7.5's the weaker they become. A 4.10 gear in a 7.5 only has a 1.5 tooth contact pattern. Very easy to shave the teeth off. 3.73's aren't much better at about 2 teeth.
If all you want to do is run these 10 bolts I'd stick with a set of 3.23's or 3.42's and call it done. I've seen quite a few 3.23 equipped cars well into the 11's.

**oldmanZ28** · 12-09-2010, 02:23 PM

^^^ agree.! The OEM GM 7.625 gearsets of 2.73,3.08,3.23, & 3.42 are 'strong' sets.
When we bought these cars new,the rearend was part of the 'warranty',aftermarket gearsets don't come with 'warranties'.

**TLS_Addict** · 12-09-2010, 02:49 PM

T-top weatherstripping came with a warranty as well. How did that work out for some people? lol

Quick question though. Would a "thick" ring gear be stronger than that of the "thin" ring gear? Just wondering.

**Firebirdjones** · 12-09-2010, 03:00 PM

Why? Are you thinking of going with a 3 series gear on a 2 series carrier??

They do make the thicker gears as well as thinner gears to go the other way. I've setup a few 12 bolts like that going both ways and haven't had a problem.
Did a thin gear setup on a 12 bolt in a 69 camaro many years back. Moroso 4 series posi (the only way they come) with a thin 3.73 gear. Car had a 720HP 496 in front of it with a pro shifted 4speed manual. That car ripped, and the rear held up for years without a problem.

Can't say on the 7.5 though, I'm not really a fan of setting up steeper gears in the 7.5's. Pinion gets smaller with more gear, less teeth contact because the ring gears are so small in diameter.

**oldmanZ28** · 12-09-2010, 04:14 PM

thick gears/thin(regular)gears are same in strenght.
for example 3.73s'.-same ratio,same number of teeth on each,same size of teeth on each,thicker gears have more material (approx. 1/4") UNDER the teeth to make up for the distance difference between a 3series carrier and a 2series carrier.

**allbaugh_04** · 12-09-2010, 05:49 PM

Originally Posted by Firebirdjones

I can understand. Don't really know how much racing you plan to do, but an auto with the 7.5 and very mild gears could last a while. I've seen alot of them in the 11's still running stock gears.

The more gear you put in these 7.5's the weaker they become. A 4.10 gear in a 7.5 only has a 1.5 tooth contact pattern. Very easy to shave the teeth off. 3.73's aren't much better at about 2 teeth.
If all you want to do is run these 10 bolts I'd stick with a set of 3.23's or 3.42's and call it done. I've seen quite a few 3.23 equipped cars well into the 11's.

Good info, thanks for sharing. Learn something new every day.

**TLS_Addict** · 12-10-2010, 12:37 PM

So is a series II set of gears "stronger" than a series III gear set with the same ratio?

**oldmanZ28** · 12-10-2010, 12:58 PM

of the same manufacturer and of the same manufacturers' series(not to be confused with our topic of 'series') gearsets,NO.

**Street Fighter** · 12-23-2010, 12:47 PM

Originally Posted by allbaugh_04

That's the thing...the car is worth what..7-8k at this point. I have a hard time putting forth that much money. Money isn't the issue, it's just doesn't seem smart on a car that's only worth this much.

If you put everything on your car based on what it is worth, you want be doing too much to it in the line of performance. It's a true saying (you have to pay to play). I have found that sometime the cheap move is not always the best move. If I had the money I would get a new rearend and be done with it,knowing that any beating to be done to it will be done by me.money well spent.

**nomolos1** · 12-26-2010, 05:05 AM

If my rear were to break, what rear would be best for economy? I have an auto. I get about 20 to 23 mpg. I don't know the size of the rear at the moment.
Please don't hate on me. I've already got a 600 rwhp car. (supra) I just wanted a nice sporty DD, that I can enjoy. I get many complements on the T/A.

**oldmanZ28** · 12-26-2010, 06:37 AM

98 T/A Auto getting about 20-23mpg PROBABLY has a GU5 3.23,98s' had Auburn posi.
The above is assumming the vehicle is STOCK.

**Demon_Z28** · 12-26-2010, 09:22 AM

Originally Posted by oldmanZ28

98 T/A Auto getting about 20-23mpg PROBABLY has a GU5 3.23,98s' had Auburn posi.
The above is assumming the vehicle is STOCK.

only if it was a Camaro SS in 98 then it had an Auburn Posi, my 98 Z28 didn't have an Auburn Posi, but I had 2.73's too.

My 6 speed blew up a 10 bolt with an auburn posi w/ 3.73's, not that much stronger then the torsion.

**oldmanZ28** · 12-26-2010, 12:13 PM

98 Zs' HAD posi.

**nomolos1** · 12-26-2010, 12:45 PM

SLP loudmouth, K&N, And that is all

**Demon_Z28** · 12-26-2010, 01:14 PM

My Z28 (2.73's) with full exhaust and LS6 intake manifold on street tires ran a 13.3 @ 106mph with an easy 2.1 60 foot. So the taller gearing doesn't kill it too bad but I could of been running high 12's with 3.23's. My friends T/A on 245/50 R16 MT DR's ran 12.8 @ 108 mph, he would kill me from a roll of about 1 to 2 cars after he was tuned. When he was un-tuned we were pretty damn even from a roll. It was usually who ever got the hit first. But his gears helped him at the track by a lot and so did the tires. But you get the idea.