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73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: Jakethesnake73 on September 25, 2015, 12:13:44 pm
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Ive got 3.73 and a limited slip rear i believe.
Im tunning 33 inch tries and my top speed is about 85-90.
My revs arent very high when i hit this top speed so i feel like im not taking advantage of 100% of my power.
Will 4.10s give me a better top speed?
Will i need a new posi unit
Cost?
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I got a quote a few years back from an off road shop in Northern Kentucky, they wanted almost 4K to change my 3.08 gears to 3.73 in my 78 K10 this was open diff - no limited slip
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What do you have for axles?
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The two answers are a lot of money if you do it yourself and even more if you have to pay someone else.
Plan on at least $120 per ring and pinion, $100 per gear set up kit, $400 -$500 per LS. If you decide to put just open carriers you could save a few $$ but really when you are doing this job you are ahead to set it up the way you want. You probably have 3 series carriers, if you have a 1/2 ton, which will have to be changed to 4 series carriers. You are going to need some special tools such as a dial indicator to check backlash. You are going to need a beam style INCH torque wrench. You can not use a click style torque wrench.
When you are doing this job you probably will check ball joints, spindle bearings and wheel bearings etc. So there is more money. I don't mean to discourage you but the fact is that it costs a lot of money to go with new parts. A lot of guys just look for another front end and rear end to roll under their truck to keep from doing a ring and pinion change. That is the cheapest way to go though.
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heres my take. im with everyone else about the cost, its not worth it for a dd. now if it was a mud truck or something off road or race truck then i can see it. i would swap axles for a couple hundred then maybe find some 8 lug 15" rims so you can keep your tires. if you with ¾ i think you have a good chance of getting 4.10s and i dont think a junkyard would mind if you pop the cover to get the right ratio. might even be able to get a adapter for your rims to fit the ¾ ton axles so that will save you some money, but do some research on the adapters to see how much they can hold
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Always pop the cover and check the ratio
Seller will lie and say it's whatever you are looking for
Also good time to inspect condition of everything before you buy
I've called about s couple and tell the seller that I'm bringing tools and will pull the cover before I pay for it
If they don't want you to do that , then there's s reason ,
A socket in cordless drill makes it about 2 minutes to get the cover off
Always cheaper to buy a mother set of axles
Setting up gears is not a Job for a novice
It takes years to learn how to do it right the first time
Where you at ?
We're looking to sell off our 3.73 14 bolt and Dana 44
Gonna go to 4.56
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not to mention you have to buy special tools for the job
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I just got a quote from a driveline shop here locally for mine. Going from 3.08 to 3.73 or 4.10 front and back with new bearings and seals, new front axle u joints, and a truetrac rear differential is going to run me 2200$ installed. I'm leaving the front carrier open. Hope it helps.
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not to mention you have to buy special tools for the job
The only two tools you really need are a bar type torque wrench a 0 dial indicator with a magnetic base.
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and i dont have either lol might have them at the shop but in my personal tools i wouldnt use it for much of anything else.
yeah leave the front open so you can safely drive it in 4x4 on the road.
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Just a side note related question,,
How can you tell what your rear end gear ratio is? 4:11's, 3:73's, etc, etc....
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theres a couple ways one is to pop the cover and divide the number of teeth on the ring to thr number of teeth on the pinion. (its stamped into the ring i.e 41 10 =4.10) you will see other numbers but it should be the last ones
or
http://forum.73-87chevytrucks.com/smforum/index.php?topic=30546.0
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If I understand your question right going to 4.10s from 3.73s will actually lower your top speed while increasing your acceleration. It'll take .37 more turns of the drive shaft to make one complete rotation of the tire.
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Yup