I have a 94 Z auto with the economy package - 2.73 gears / series 2 carries.

I want a 3.42 gear ratio when I finally get my new 383 installed (just taking some time/money

Option 1 - take my OE rear end - buy a set of 3.42s and a rebuild kit from Summit and have my good buddy (whos a certified GM drivetrain specialist) install it

Option 2 - find a used OE rear end from a camaro that was equipped with 3.42

Which OE rear ends will work BEST if i decide to go that route? Which rear ends are interchangeable with my 94 Zs? Computers, Posi Units - compatibility is another language to me. Anybody ran into this delimma?

 

Take yours, and make it stronger. Use all new components and certainly replace the posi unit.

 

Trying to make a stock 10-bolt stronger is a fruitless endeavor. Go with a 9", 12-bolt or S60 if you can!

 

PLEASE post in the correct forum. This isn't an "engine" topic.

Moving to Drivetrain.

 

Are OE posi's weak? Do they eventually fail because of the torque of added hp OR the volume of miles over time. Mine OE posi has about 150k miles on it...

 

GM used Auburn 'posi's' since the 60s',maybe even the 50s',they are a good posi.
Unfortunately,GM used the 7.5/7.625 10 bolt in the Camaro/Firebirds since 1982 and did not upgrade them in size/strenght as the f-bods increased in power.
The little 10 bolt was fine for its' original design use of low power daily drivers.
Auburn posi's were used up to/for the 1998 models
They do wear out,the cone clutches wear out with time/usage,probably would not have been any different with Eaton clutch plate posi's either.
With 150,000 miles on it,it's probably wore out.
Breakage due to increased power typically occurs to the Auburns' spider gears.

Your option 1-you would need an aftermarket 'thick' set for 2 series carrier and 'rebuild' kit. With 150,000 miles,your Auburn is probably wore out and you would need a carrier.If you had to replace the carrier,that could probably change your gearset part number purchase iof you acquire a 3 series carrier and then don't require the 'thick' set.
Your option 2-pick up a used OE 3.42 rearend.Since your car is a 1994,you would be limited to a 3 channel (ABS only) rearend. I would recommend looking for a 1994-1997. 4 channel (ABS with Traction Control) started in 1995. Since you're after a 3.42,that would be coming from a 6 speed car. Some V6s' had 3.42 and posi,but they would have drum rear brakes.
you would need your computor 'tuned' to correct speedometer.
Since your automatic,why are you bypassing the 3.23s' as an upgrade ?

 

Interesting reading, showing that even dumping more than $1,500 into the stock rear does not gain you much.

http://highperformancepontiac.automo...ild/index.html

http://www.highperformancepontiac.co...ild/index.html

 

[QUOTE=Your option 1-you would need an aftermarket 'thick' set for 2 series carrier and 'rebuild' kit. With 150,000 miles,your Auburn is probably wore out and you would need a carrier.If you had to replace the carrier,that could probably change your gearset part number purchase iof you acquire a 3 series carrier and then don't require the 'thick' set.
Your option 2-pick up a used OE 3.42 rearend.Since your car is a 1994,you would be limited to a 3 channel (ABS only) rearend. I would recommend looking for a 1994-1997. 4 channel (ABS with Traction Control) started in 1995. Since you're after a 3.42,that would be coming from a 6 speed car. Some V6s' had 3.42 and posi,but they would have drum rear brakes.
you would need your computor 'tuned' to correct speedometer.
Since your automatic,why are you bypassing the 3.23s' as an upgrade ?[/QUOTE]

Im bypassing 3.23s because this car will be used strictly to blast around town. I figure 3.42s will be a little more appropriate.

If im limited to a 3 channel ABS, is a 4 channel ABS rear end all I need ( and a tune) ? I can begin to look for a rear end from a 95-97 six speed fbody? My car is in a 1000 pieces at the moment. Im waiting on a few parts.

 

NO,you CAN'T(repeating what I said in post #6) use a 4 channel rearend(incompatable control/electronics),you're limited to using 3 channel rearends.
And if you do your option #2,you'll have your original rearend as a backup.

 

The reason I brought up a used complete OE 3.23 rearend is that a 3.42 rearend would have to come from a 6 speed (which is more abusive to our little 10 bolts and probably would have annoying gear whine),where as a 3.23 rearend would come from an automatic and would not have been subjected to 6 speed shock loads.

 

Yukon Axles
Eaton Posi
3.42 Ring Pinion
Full Rebuild KIt

Starting to get a little expensive...

If I were to go this route, how does my series 2 carrier and 2.73s factor in? By replacing all internals(ring pinion,posi and axles), which gears and carrier would be the most practicle to purchase? The series of the carrier and the thickness of the gears and their interchangeablity are confusing to me.

I want to build this 10 bolt as effectively as i can on a budget. Im not gona put more than 425 rwhp to this rear end. Auto tranny. Vig 3600

 

that route,the 2 series carrier doesn't factor in at all !

How many miles on the OE 2.73 2 series carrier ?

 

I just destroyed my stock axle 3.23 gears GU5, and replaced it with my buddies GU6 3.42 axle from his 6 speed.
You can get axles for under $100 at pick n pull type junkyards. I would never put $300+ into a stock axle to regear it just to get the same thing as stock.

 

I got 150k on my OE rear end.

What is the carrier in a rear ends pupose? Why are there diffrent series? Is there an online diagram anywhere?

 

The "carrier" is the basic internal. The ring gear bolts to it, and it "carries" the gears internally that allow the two axles to move at two different (hence, "differential") speeds when turning a corner. If you have a limited slip differential, there is a set of clutch plates added to the carrier internals, that lock the two axles together when one wheel starts to slip. There are also other types of limited slip setups, including cones, torsion sensing systems, etc. But for the Auburn and Eaton limited slip its done with clutch plates.

Heres an Eaton carrier:



The ring gear bolts on to the left side, the axles enter the center of each side. The entire carrier sits in two support bearings that mount to the differential housing.

A 2-series carrier will work with numerical gear ratios up to 3.08:1. From 3.23:1 and numerically higher, you need a 3-series carrier. The difference is simply dimensional. If you were to buy a new carrier (including the limited slip feature), unless you foresee the day when you might want to go back to the 2.73 gears, you would buy a 3-series carrier.