Gears and Gas Mileage

[nubuilder]

I've been looking for a posi rear end for my S10 since I got it and haven't had much luck at all. Well, I just found a complete axle with a posi, but it has 3.42 gears in it (I currently have 3.08's). Its cheap, $100, but its also 3.5hrs away one way. By a calculator I found online, here, my RPM's will go up by 200.

How much is this going to affect drivability and MPG's? (as my S10 is my economy vehicle so I do really care about it)


Being that it is so far away, should I just find a carrier and install that? (such as this one, which could be the same cost in the end) But that would mean going through shimming and all that jazz or not?

Thanks!

 

[NMRam]

I doubt you will see a significant drop in MPG's. Sometimes, you will actually see an increase with lower gears since you don't have to work the engine as hard to build and maintain speed. BUT, if you swap gear ratios, you will either need a tune or an updated speed sensor or your speedometer/odometer will both be off.

 

[nubuilder]

I doubt you will see a significant drop in MPG's. Sometimes, you will actually see an increase with lower gears since you don't have to work the engine as hard to build and maintain speed. BUT, if you swap gear ratios, you will either need a tune or an updated speed sensor or your speedometer/odometer will both be off.

Yeah I knew that would happen if I changed gears.

 

[4.6 Punisher]

MPG's will drop slightly, but it will be slightly better on acceleration. I would recommend that you get a master install kit that has the bearings.

 

[Bigredmariner]

Matt, doing a gear change isn't all that difficult but there are a few tools that you either have to have or have access to. Look this over and if you have questions feel free to ask.

http://www.truckmodcentral.com/forums/showthread.php?t=11732

 

[nubuilder]

J-rod, your write up makes me really want to do a carrier install, but I don't have the specialty tools.

Basic hand tools, brass punches, hammers (I only have a small carpenter's), slide hammer puller (can rent from AutoZone), bearing pullers (can rent from AutoZone), torque wrench, inch pound torque wrench and a shop press. An appropriate jack and jack stands or a lift if you have one. You will also need a set of good slide caliper or a 1 inch micrometer, a dial indicator with magnetic base, your setup bearings and gear paste. ( the paste is included in the master install kits).

And now that I just parked my Silverado, the S10 is my only vehicle. So I'd need to do this over Christmas break if I were able to get all my ducks in a row.

I think I'm gonna try to find a 2-series carrier and see how much it and an install kit would cost.

 

[Bigredmariner]

If you are out pricing bearings and/or gears you should include Ronsmachiningservices.com in your pricing. Give him a call to compare his prices with what you need, very helpful man, fast shipping and quality parts.

 

[nubuilder]

I still need to figure out how many splines my axles are. All I know for sure is it's a 7.5" with 3.08's.

Would you recommend getting new gears if I do a carrier install (of course if I'm doing a carrier, I'm sticking with my 3.08's)? Obviously if the gears are worn, they would be replaced anyways.

I'm checking out that site, along with eBay and CL to see if there are any carriers closer to me (other than being a 6hr round trip to get it).

 

[svensk]

I recommend 4.56 instead...

Edit - And tiny tires

 

[nubuilder]

I recommend 4.56 instead...

Edit - And tiny tires

I don't know....my 4.3 might roast tires with 4.56's and my 27" tires . Might be able to fit a 14" rim and get down to some 20" tires if they make them .

If I had a 350/383 in it with a t56, I'd like to go with 3.42 possibly 3.73.


But seriously, anyone have any idea on how many splines? I'm seeing either 26 or 28.