3.08 to 4.56 gear change

[junior3382]

Is there a web site to go to that any one recomends to carry the complete replacement kits for upgrading your gear ratio?


I am not looking to actually do this till summer, but as some of you know, I research the krap out of everything before I decide to do it. Everywhere I have looked will only give me replacement OEM parts. I know it is out there. Perhaps I am not searching for it right. So a starting point is always helpful.

[Hayden]

try this General Motors Gear Sets

[junior3382]

Are those prices for the whole set? I mean I thought it was like 1400 bucks to swap out the gears?

[junior3382]

Also look at this.....


JawsGear.com


If I am reading this whole page right and the subsequent links, there are lockers for IFS??????????? I thought you could only get them in solid axles????? Is this right? Can I get lockers for both the front and the rear? Is it worth it?

[junior3382]

I know ton of questions, but when looking at some of these sites, they say 7 1/4 rear, or 8.2" rear and so on. What are they measuring? What are these dimesnions?

[crabtruck]

This is the area where 75 could make a ton of money just holding class
but he is so in to it, he probably wouldn't charge anyone just so he could play !
Search the threads for this stuff, you'll find lots of good reading with contributions by him and others.

[75K30]

crab always has such fun things to say.
With regards to your questions, we should start with what the numbers 7.25" and 8.2" actually mean.
These are the ring gear diameters. GM had plenty of different sized ring gears, and the larger the gear, the more contact area it has with the pinion, and the larger the pinion can also be, so in theory, the stronger the package. There is also a levereage factor here, even at equal ratios. It becomes much easier to turn a tire of equl size with a larger diameter ring gear, than it is with a smaller one. Now, a real purist will argue that the larger gear is heavier, thus making this about an equal compromise. Yes it does take more power to turn the larger package, but this is not the arguement just yet.
try Randy's here for complete information Randy's Ring & Pinion
this should help you out a little bit.
Here is a link that will give you an idea about what you are getting involved in.
I could, or would be willing to assist, but it would require that you live close enough to drive a truck over to the shop. Otherwise, learning over the web is tough at minimum.
As far as the locker, I believe that the only availabe unit for these smaller front ends is a "lunchbox" locker, and I never recommend them in the front of an IFS truck. These diffs, and axles are way too light duty to survive with the added load of a locker. These front ends barely survive with open diffs. An open diff is like a "fuse", when traction gets too high, the differential allows power to go to the tire with the least resistance. While this is not the best for foward motion, it does allow the torque of the engine to go somewhere, instead of Kaboom! If a locked differential cant displace this energy, it will find a way out, and usually broken parts are a result, especially in the front. Larger axles that are more extreme and up to the task are a different story, but these small axles are just not ready.
The rear is also pushing it, but I would feel quite a bit more comfortable running a locker in the rear, with an open front.
Believe this or not, your truck with a rear locker will be almost as effective in 2wd as it is with open front and rear diffs. 4wd will only be required when things get real bad, and I mean real bad.
Most people are amazed at how much more capable a 2wd with a "real" locker can be. Then add the addition of the front end, even if it is only one wheel, the trucks can be very very capable with this configuration, and a little easier on parts.

[junior3382]

The purpose of this is to consider what larger tires will need to turn with enough power for usfullness off-road, and giddy-up on road. I do not want to feel scared to get out of an intersection because the gearing is too low. I never intended to install lockers up front, I was just told that they do not exist. However, if I use them in the rear, you are suggesting i may not need my 4wheel drive to effectively navigate some trails? That is kind of cool. From what I can tell using this chart...
4Lo.com :: Gear Ratio & Tire Size Chart

I should be running at least 4.56 ratio to turn 33-35 inch tires and maintain the control and power I am looking for. Right now it has 3.08 and I am afraid it will not be enough. I do not know how to shop for these or even much about them. Not my area of exptertise like it seems to be yours 75, and I would love to come to the shop, shame that is like a 2700 mile hike for me...LOL. If I buy lockers for the rear, should I upgrade the ratio at the same time? I know you and I have discussed this many times for other purposes, but I get nervous when looking into something i do not know everything about. Know what I mean?

[75K30]

Yeah bud, I can appreciate your apprehension.
I also have to take a line or two to apologize to crab. I believe he feels that my response had a negative tone. I did not. I guess pehaps my typing method, and material is rather dry, and when read from another perspective, it could come accross wrong. I think you ( junior) and I had this discussion not too longa ago.
Anyway crab, no ill intentions on my part.
Alright, I do believe that a rear locker would provide a better level of off road performance to any rig, but it does bring with it a cost. There is always a sacrifice. Tire wear, ice, or snow driving (any slippery surface really), and tigh turns are all compromised by adding a locker, as well as the above mentioned reliability. It will take its tolls on axles. Really tough on them.
For the same reasons that a locker can kill a front axle, it shares the same troubles if placed in the rear. As you can see in the attached thumbnail, even a fairly strong 9 inch with a locked rear and a nodular case can break. This was with small tires.
If you decide to install a locker, and it is a real locker that replaces the actual carrier, then you really have to change it while you are changing the gears.
I recall that you are not a real hardcore wheeler, so I might just suggest that you leave this alone, and stick with the correct gear choice. You are looking in the right direction, and your ratio is very correct. I like that tire size, and the 4.56 ratio. Brings ratios back around factory specs.
I would simply give the tech guys at Randys a call to see what they recommend and verify which parts you need.
As an example, they will probably recommend a master install kit for both nds, and new rings and pinions. This will be a complete re-build including bearings. There are kits available that have just seals and such, if yours are in good shape. Just have to look and see if you actually need new bearings. If not a standard install kit with selas and shims may be the only thing that is necessary. Front and rear will run around 1500 bucks with labor. The parts are not all that expensive, and roughly around half of the total cost. It works out much better to buy the parts from the place that installs tham, and you do not have to do much leg work at all. In the event there becomes a warranty issue, you will have less to worry about. If you bring them parts, and ask them to use your stuff, you will never get any type of warranty, and you could find yourself spending a bunch of money, when it is not necessary.
This is something to think about. Now the burdon gets placed on the shop that performs the work, and you get an extra benifit from your investment.

[junior3382]

Ok thank you. when the time comes to make the change, I will let the shop I am using take care of finding and ordering and installing that parts. I like to know what I am getting into. I will probably skip the lockers only because this is not "hardcore" as you mentioned. I toy with a lot of ideas before I make a choice. Part of the reason I have so much unsed and sometimes unescesary information in my head....LOL. I am looking at spending some big bucks on this truck all together now. Have been saving for a long time. I am the type that wants to do it all at once instead of peice by piece, or it will never get done right or things will break and add to my frustration. I have settled on total hieght and parts for lift and accesories. Have also settled on tire brand and wheels, not quite yet on size. May start with 33's only because I KNOW they will clear, and maybe upgrade when they wear out to 35's. That is still in the air. I just do not want to go half way and stop. I think sus lift, body lift, Brakes, rims, Tires, Push bar, Light bar, off-road lights, Dual exhaust, Throttle body spacer, intake and many more all at once will be more enjoyable. Like a whole new truck! I wanted to know more about gears to add to the mix. I know this is a lot for a little blazer, but has sentiment to me...LOL. I appreciate all that I have learned and all the help I have gotten with these off the wall and random questions. Of course I am aware of added wear and such, but I think all at once would cut down on the little oopsies between time. Like running large tires with no compensation. In the end, I think I will save money by not having to fix broken parts in the meantime. Make sense? Anways, thank you guys for your quick responses here, and dealing with my sometimes repititious questions.....LOL. It is appreciated.