I know this topic is covered a LOT (I've been doing a lot of searching), but each situation seems to be so different and nobody I saw (in previous threads) had quite my setup. The information may be out there but its really scattered and hard to put together. Hope you guys don't mind my asking .

Anyways, before I get to what I WANT, this is what I HAVE:

1992 350 TPI Auto (Camaro) with 700R4 and 9-bolt 2.77 rear end. When looking up a gasket, the guy at the parts store measured the cover as 7 3/4", if that helps.

I know this information is correct, even though I didn't think I had 2.77's.

I really want 3.73's but I know its not a good idea for a TPI, plus I don't want to deal with the mileage and higher rpm on highway issues.

So I've pretty much settled on 3.42's.

Here are my questions (there may need to be more that I don't know!):

1) What's the difference between 3.42, 3.43, and 3.45? Besides the obvious effects, is it just a matter or gear selection or does only one fit with THIS size, or with THIS (x)-bolt rear, etc?

2) I've got a 9-bolt, so do I need a new differential completely? In doing my research I assumed changing "carriers" meant changing the differential to accomodate different gears, but then I saw that they're not the same? Can you clear this up and will I need a new differential?

3) Related to above question, what "carrier" do I need?

4) What's a good gear selection (brand-wise) for a mild application (eg: I don't want the cheapest crap but can't afford the REALLY good stuff)?

5) I've got the 700R4, and from my research I'm guessing I have an electronic speedo because I'm a '92, right? So what do I need to change to make the speedo read properly? I saw a lot of contradictions in my searches. Some say "these speedo gears" but some say "those only work with electronic/cable driven (choose one)". What's the final answer for my application?

Again, thanks so much. I really only ask because I couldn't gather all the information for my application. Thanks so much!

 

You will need a series 3 carrier to run the 3.45 9 bolt ratio. The series 2 is only good for 2.77.
3.42 is a 10 bolt ratio
Someone must have swapped in that rear as they did not come in 92's. There is a web page that has all the info you need on 9 bolts.

Miles

 

try www.9bolt.com see if they have anything you want or see what they have that will work for you and be sure to tell them i sent you, you might get a discount

 

That's what I suspected because they gave me 10-bolt gaskets twice at different parts stores. Thanks for the clarification! I'll post again if I have some more questions.

 

WOW thats expensive! Are there cheaper alternatives??

Not to mention I still have to pay for installation! How much does that usually cost?

 

there aren't many if any options for a 9 bolt, figure 3 hours labor

 

Is there a junk-yard group of parts I could find that would work? Like a 9-bolt posi 3.45 from "this year" or a 10-bolt 3.42 unit from a different year?

 

9 bolts were kind of rare to begin with. It was more or less an upgrade off the 10 bolts. Then you have to figure that most 9 bolts came with 3.27 gears (mine did) GM has parts listed but they've been discontinued. Miles can hook you up, you might even beable to get a used gear off him. I know he sometimes carries them.

 

Will you guys take a look at that NEW but chipped gear set for $150 on that site and the USED set for $75 (both [URL=http://www.difftechnics.com/used_parts.html]here[/URL ) and tell me if either are worth using? That would save a lot of money but I don't know if it would be a disaster or not. Thanks.

 

Ok I've got another idea here......

I went to SLPonline and put together a set that I think will do it for me. There's a 3-series 10-bolt differential I can get (p/n 64501T), gear set for 3.42 (p/n 64048) and installation kit (p/n 64047) I can get shipped for less than $500. Assuming I have 28-spline axles (is there any reason I shouldn't?), would this set of parts work for me or am I missing something? Thanks.

Note: If I don't get any replies from here, I'll post again with this part as my original question. Thanks!

 

You just swap to a 10 bolt... just a thing to remember a 9 bolt should be stronger and might last longer than a 10 bolt at high stress.

 

Yeah thats what I thought I was doing......will it work with those parts?