Will a set of 3.42 gears from a 4th gen fit into my 3rd gen rear. I have a 7.5 10 bolt and so does the person that I am buying them from so logic says it will work. So will it?

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"I'm not dumb, I just have an amazing command of thoroughly useless
information."
Bill Waterson creator of Calvin & Hobbes.

 

Is he just selling the gears, because you could swap the rears.

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"Rice burners are like tampons...Every pu$$y has to have one"
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite

 

Yes, maybe. The 7 1/2" and 7 5/8" gears are interchangeable however there are series 2 and series 3 carriers. 3.42 gears should be series 3. If you're trying to put them on a series 2 carrier, they won't fit without a spacer or a new carrier (posi, torsen, etc)

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87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block (times are for the current engine)

Best ET on a time slip: 11.447 altitude corrected to 10.99
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Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

Sorry about that I should have cleared a few things up. I have a posi 3.08 rearend. He is just selling the gears becasue he still has the rear in his Firehawk so that is out of the question.

 

Are you sure his gears are GM 10 bolt and not Dana44? The Dana44 also has a 10 bolt cover but the rear cover has a metal fill plug in it. I'm pretty sure the Firehawks came with Dana44's but not sure if they were still available for the fourth gens.

 

He said that he has a 10 bolt 7.5 in his car but I will ask to be for sure that those gears are for a 10 bolt and not a Dana44. So if they are for a 10 bolt would they still work or am I out of luck?

 

The only Firehawks that came from the 'factory' with Dana 44s were the 91-92s. The 4th gen Firehawks all had 10 bolts from the 'factory'. The HD Zexel carrier was also only an option on them so a lot of them ended up with a plain 10 bolt with a T-2 Zexel differential just like every other Z28, T/A, or Formula...........

Sorry about this Evan, I forgot all about the carrier series issue. Since you have a 3.08 gear right now, you have a 2 series carrier. The gears that Todd has for you are from his stock 6-speed Firehawk which has a 3 series carrier (anything with numerically 3.23 gears or higher is a 3 series carrier and anything under, is a 2 series carrier). I should have thought of this before, but I tend to be a dork a lot of the time . So what you will need to do is get a hold of a 3 series posi carrier that has the same spline as your current one (26 spline) and you can just bolt the gears to the carrier and throw them in (setting backlash and whatnot of course). They do make spacers for a 2 series carrier to be able to accept a 3 series gear set, but I don't recommend that since it is not as strong.

You may just want to go through the whole rear axle while your at it and; upgrade to some Moser hardened axles (~$225), a T-3R HD Zexel-Torsen 'posi' carrier (~$399.95), a TA Performance girdle with bearing cap stud kit (~$150) and those 3.42 gears from Todd. At that point you have a green light for beating on the rear end all you want as your transmission will break looooonng before the rear axle . I have seen cars with similar upgrades to their 10 bolts (axles, carrier, gears, girdle) run DOT drag tires and pull 11 and even a few 10 second ETs without blowing up their rear axles. Of course, there are other more expensive rear axle options out there that would handle much more power than a 10 bolt....... It comes down to money - gee, what do ya know!

You can also run the regular T-2 'posi' Zexel (OEM carrier on most fourth gen 10 bolts) which would run you $100 from SLP (instead of $400 for the HD Zexel) and cut $300 from the overall price of the entire operation. It is not as strong as the HD Zexel, but it would be more than adequate for your current engine and can ALWAYS be removed and replaced with a stronger carrier later........

So looking at this as a tight budget situation, if you get those gears for the price that was discussed, than pick up the $100 SLP takeoff OEM posi from a fourth gen, it will get you where you need to be with the carrier being a 3 series so the gears will bolt right in. The only down side is that I am 99% sure that your axle has 26 spline axles and even the OEM carrier from a fourth gen will have the larger 28 spline axles...... Sooooooo - you will have to buy axles and why not just upgrade to some hardened ones from Moser and be done with it!! Sounds so easy doesn't it!!


Well, those are some ideas for ya
I'll talk to ya Laterzzzzzzz 'bout this stuff.....

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

Thanks a lot Matt you just confused the living hell out of me. I think that I have a handle on what you are talking about. So all in all I would be spending about $900 on everything and not really have to worry too much about breaking the rear end. But couldnt I just go out and get a 4th gen rear and have a stronger rear but just have my tires stick out like you. :P

 

Punk............



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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

The 4th gen rear is the same strength as the 3rd gen 7.625 rear.

If you want something stronger (in order of cost and strength) then:

9 bolt (~1/2 the cost of the others)
12 bolt
Dana 44
9 inch

Miles

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88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES, it is a 9 bolt & YES they are 3.73's, not 3.70. I currently have 4.10 gear sets and new series 3 carriers in stock for 9 bolts )
www.koolmeister.com

 

Don't worry about that comment Miles, he is just taking a shot at me........ little punk.......

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

yea I was actually taking a shot at Matt. I am actually thinking about saving my pennies and ordering a 9" since people really like those for strength.