LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Changing Gears (2.73 To 3.42)

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Old 01-27-2006, 12:04 AM
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Default Changing Gears (2.73 To 3.42)

There are three mods I'm for sure going to do this summer, if it kills Me. One of those being Gears, the other two being Full Exhaust and Window Tint. I'm tired of the 2.73's, they need to go. And I'm saving up money to do some mods this summer, once the weather is better in old SD.

I'm looking into Strange and Richmond gears... But I'm not sure if Richmond makes the "Thick" gears required for cars equipped with 2.73's and the 2 series carrier. Would it be beneficial to chance from a 2 series to a 3 series carrier? If it's possible? Or should I just go with the Strange 3.42 "Thick" gears? I've heard the Strange gears can be noisey at times, which I don't really want... but could tolerate if must be.

Also, I would like to get a full gear install kit obviously, and have heard that the RaTech gear install kits aren't the best, and would like to know who else makes them? Or if I was just hearing wrong?

I plan on installing the gears myself, with the help of a friend or two... but since I haven't worked on F-Bodys much, how much of a task is it? I would like to get the experience before going to WyoTech, but don't want to mess it up if it's an extremly complicated task for a guy who only has a shed for a couple days, before I have to clear it out for my Grandpa's Trucks to get in... plus we only have a floor jack with stands, no lift or anything.

Any help would be appreciated, trying to plan out how much money I'm going to need for this project.

EDIT: Also, I've heard that I will need some special adapter to adjust my speedometer correctly for the gear change. I will probably get my rims/tires (Graduation) before I do the gears, so it wouldn't make since to buy an adapter or whatever until then anyway. But does anyone have info on how to change the Speedometer considering my Car is a SPEED DENSITY 93 Z28? I think Dakota Digital might make the adapter.

Last edited by Renegade; 01-27-2006 at 12:47 AM.
Old 01-27-2006, 12:14 AM
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i would upgrade to a 3 series carrier because of it being alittle "beefier". Richmonds are the gears that are notorious to "whine" all the time. As for the Ratech install kit i bought it and it looks like a good kit to me. all of my other friends have used it numerous times with no problems. i would also invest in a solid pinion spacer. you can also weld your axle tubes so they wont twist. and as for setting them up, i would let someone who knows what there doing install them. gears have to be EXACT for them not to "whine" and wear wrong. to get experience before school isnt worth messing up expensive parts. im sure ull have plenty of time to learn how in school and ull get all the ins and outs and special tricks to installing gears. just take it to a professional right now
Old 01-27-2006, 12:51 AM
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Thanks for the info Schweet97z. It sounds like the 3 series carrier would be the best bet, can I buy that from whoever I get the gears from? I'm not sure what a carrier is exactly, so it's a little confusing to Me. But then my only decision sounds to be weather to get the 3 series gears from Motive or Strange, the price isn't a huge difference, and maybe I will get lucky and find a good price for slightly used gears in the for-sale section or something like that. It would also be good to hear from anyone else who would like to chime in, of course I haven't made a decision yet, and there is a lot of knowledge creeping around on this board, espically in some of the areas I don't have much experience in.

I will probably have a good friend of ours who runs a little shop in town do the gear install, he is a Chevrolet Master Mechanic, and has been drag racing since he was a kid... helps his kid run a 10 sec 3rd Gen old Nutcase would be interested in seeing. That way I could probably help him out and learn a thing or two, as well as have someone trusted and knowledgeable guiding the way. He replaced my opti-spark earlier this month, because I didn't want to mess it up trying to learn on my car that wasn't running.
Old 01-27-2006, 10:09 AM
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If you want 3.42's it would be a lot easier and cheaper to put in a complete 3 series 3.42 rear axle out of a 6 speed car. I bought mine for $100.
Old 01-27-2006, 10:19 AM
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That would actually be a pretty good idea... I'm gonna have to check around the for-sale and all that and see what I can come up with. It's not like brand new gears would make a big difference when I can get the factory gears out of a six-speed cheaper.
Old 01-27-2006, 10:34 AM
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i just my rear end done a few weeks ago!!! about $540 that includin laber!!!! $35 and hour!
Old 01-27-2006, 02:09 PM
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Originally Posted by 95formulalt1
i just my rear end done a few weeks ago!!! about $540 that includin laber!!!! $35 and hour!
Wow, I've heard that people can have it done for as little as $150 bucks, it will probably run about $200 for labor, but it will be worth it to know the job is done right.
Old 01-27-2006, 02:52 PM
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If you deliver it already disassembled it is cheaper. I would spring to have a competent rearend shop set it up, though, because it takes some special knowledge, experience and tools. I think if you bring everything ready for assembly you could have it done for around $200.

Does your 93 have the 4L60 or the 4L60E? I know the 4L60 speedo gear is very easy to change with the tranny in the car. You just have to buy the right plastic gear and replace it. 20 minute job.

If you're into performance and end up changing your gears, why not go to a 3.73? They go great with the 4L60(E or not) tranny, and it will still look like a 2.61 in OD... Great off the line punch.

Jim
Old 01-27-2006, 03:18 PM
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Originally Posted by Renegade
Wow, I've heard that people can have it done for as little as $150 bucks, it will probably run about $200 for labor, but it will be worth it to know the job is done right.
i also had all the wheel berings replaced!!
Old 01-27-2006, 03:59 PM
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I was considering 3.73's at first, but with all the in-town driving I do, I don't want take a huge hit in gas mileage, and 3.42's sounds about right for what I'm going for. I might run spray after college to. The problem with finding someone to do it around here is that we don't have anyone who really has a ton of knowledge in the town itself. Sioux Falls is about an hour away, but I'm not sure if they have anyone who specifies in rear-end, I know they have tranny shops and all that but it's not an issue.

My car has the 4L60 NOT the 4L60E found on 94+ models... your saying I need to buy a special gear that is made for my ratio? Plus I plan on running 17x9.5 rims all the way around, and will need something to adjust my speedo to that as well. Also, would it be a major gain going 3.73 instead of 3.42? I still need to hook up and all, with the minor mods I have, I will have different rims/tires, but the only suspension work I plan on doing this year will be Subframe Connectors, and maybe springs if I end up with enough money... I'm trying to save up so I have enough money not to have to work through college.

95FormulaLT1 - $150 bucks is amazing for all that work, too bad I don't live anywhere near you or I would ask the name of the place.
Old 01-27-2006, 08:26 PM
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It's not a SPECIAL gear. It's just another GM gear based on your other parameters like tire height, etc. They have a chart and enough gears for normal applications that you'll get within about 2-3% accuracy. The gears are not expensive, less than $20.

I had that tranny before this 4L80E, and I had 3.73 with both. As long as you have good tires, the 3.73 will give you great off the line punch. With a 100 shot and street tires you probably won't be able to launch on the nitrous anyway, just hook up and then press the button. Your mileage won't really suffer. Just my .02.

More than about a 125 shot and you'll start having to worry about your pistons - the stock hyper-eutectic ones are iffy at 150HP shot, and your tranny will start to suffer unless you put some upgrades into it. $500 of Transgo parts & installation would help when it comes to that. After that the rearend will need some thought.

Jim
Old 01-27-2006, 11:36 PM
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Originally Posted by DeltaT
It's not a SPECIAL gear. It's just another GM gear based on your other parameters like tire height, etc. They have a chart and enough gears for normal applications that you'll get within about 2-3% accuracy. The gears are not expensive, less than $20.

I had that tranny before this 4L80E, and I had 3.73 with both. As long as you have good tires, the 3.73 will give you great off the line punch. With a 100 shot and street tires you probably won't be able to launch on the nitrous anyway, just hook up and then press the button. Your mileage won't really suffer. Just my .02.

More than about a 125 shot and you'll start having to worry about your pistons - the stock hyper-eutectic ones are iffy at 150HP shot, and your tranny will start to suffer unless you put some upgrades into it. $500 of Transgo parts & installation would help when it comes to that. After that the rearend will need some thought.

Jim

Thanks for the advice DeltaT... I might end up going with 3.73's if gas mileage won't make much difference at all, but will my car only be good to 120 mph, or so? Not like we drive around going 120+, but I would like to be able to have the top-end as well.

Does anyone know if TransGo makes a shift kit for the 4L60? I know it says 93-97 4L60E, and my car may be a 93 but it has a 4L60. I know shift kit's can really suck to install, but I should be able to pull that one off... and it would help my car a lot in my opinion. Then after college, I plan on doing a 383 FI motor, with a 12 bolt, gears, high stall, TH-350 or equivelent 3 speed, etc. Basically I want to turn it into a street beast, that can knock off 10's on street tires at the strip, running 93 Octane. But as I said before, right now... I just want to keep having fun with the car, nothing too major as far as mods go... espically because I'm poor and need to save up for school, or I will never have the money to do the mods I want... unless I get lucky and win a ton of money somehow lol.
Old 01-28-2006, 03:45 AM
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I hear the gas mileage isn't as bad as people make it out to be in 3.73's. I say step it up and get those. I'll get those in my auto, along with a 3200-3500 stall. I wouldn't get a shift kit, just get your PCM reprogrammed and have them make the shifts a lot more beefier. You'll need a tune most likely after gears anyways, or is it just a recalibration of the speedo? I plan on getting a ZEX kit, with a tranny cooler, with some Mickey Thompsons for the track so I can launch with nitrous, I have Nitto's on for DD.
Old 01-28-2006, 09:09 PM
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My uncle just did the 2.73 to 3.42 swap in his car, and I got to drive it today for the first time since the swap. Holy crap, it was a huge difference. That low 1st gear in the 4l60E and the 3.42 make for a nice take off . Its like a totally different car. You won't be dissapointed in this swap.
Old 01-29-2006, 04:04 PM
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Thanks for the info guys, I will probably be in the market for a rear in a couple of months. It will be one of my first mods this summer. Hopefully I can find the whole assembly without too many miles on it, from an M6 car that is being parted out or something, I would like to spend less than $300 bucks on parts if possible.

Also... where can I get the recalibraction gear at? If anyone has any more information on that?
Old 01-30-2006, 10:34 PM
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I have been driving on 3.73s and have loved the experience. I came from 2.73s and dont regret it at all. I must say that the gas mileage did take a hit. I live in Austin and the traffic is pretty crappy considering all the construction. However considerable the change in gas mileage you will feel, I am betting that it will be worth it to you. So what I am trying to say is--go for the 3.73s. You wont be upset.
Old 01-31-2006, 02:14 AM
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Remember, that 4L60 has a .7 to 1 overdrive, so the reared ratio will look like highway gears (2.61) in OD. I've had my car with the old motor (ZZ3) in it up to 155 in the flying mile with 3.73s.

Would you rather have off the line launch and everyday power or once in a while 165mph (assuming your motor is strong enough) gearing?

Jim
Old 02-01-2006, 07:40 PM
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i've got 2.73's in my 95 ta and i have a set of 3.42's waiting to go in. anyone got dyno or race results with that change of gears. i also wanted to ask if you need to add the posi fluid when you change gear oil on a 2.73'ed rear end?

Last edited by bandit95; 02-01-2006 at 07:52 PM.
Old 02-01-2006, 08:11 PM
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Here's the story: had 3.42s & carrier from a 6 speed put in October Y2K. Grenaded the hell out of them in December 2K1. Put in Motive 3.42s & SLP series 3 carrier, sheared the teeth off the pinion in October last year. Now, I have Strange 3.73s on my factory series 2 carrier. I thought the pinion would be bigger, but it wasn't. The ring does look a little beefier though.



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