What gear Ratio is best?

[PlayingWithTBI]

Start getting the parts together & attempt it. Do you guys have any recommendations on a kit or carrier?

Here's what I did on my C1500. This is copied off my build spreadsheet but you get the jest of it. I boughts the extra bearings and bored them out a little with a drum sander so I can slide them on and off while setting the pinion preload.

Pinion Bearing TMK-M802049 Timkin Summit Racing $14.99
Pinion Bearing TMK-M88048 Timkin Summit Racing $8.99
Crush Sleeve eliminator YGA-55048 Yukon Gear Summit Racing $33.06
Rear End Overhaul Kit ZKGM8.5 Yukon Gear Amazon $57.00
4.11 ring & Pinion ZG GM8.5-411 USA Standard Gear Amazon $145.11

Here's the manual that comes with the overhaul kit.

 

[Tdean91491]

So you didn’t even mess with the spider gears?

 

[PlayingWithTBI]

No, just left them alone. I did change the axle seals, forgot to add them to my list...

 

[Tdean91491]

Ahh I gotcha, I’m gunna save that list I’ll probably take that route plus doing the spider gears. Not like it’ll have my daily driver down. Probably replace everything that I can while I’m doing it. What brand dial indicator did you use for the backlash also what what brand dial torque wrench did you use for setting the preload on the pinion bearings? Or what brand would you guys recommend?

 

[randomguy]

My opinion is with 35’s you want 4.56’s at the minimum. I ran 4.88’s on my suburban with 35’s and loved it. Your MPG is going to suck either way, but it sure is nice to drive something that isn’t a gutless pig.

 

[Tdean91491]

My opinion is with 35’s you want 4.56’s at the minimum. I ran 4.88’s on my suburban with 35’s and loved it. Your MPG is going to suck either way, but it sure is nice to drive something that isn’t a gutless pig.

I gave up on trying for good mileage a long long time ago lol, I think the 4.56’s would be a better option to. Because sometime in the future I plan on lifting it 6 inches and possibly running 37’s.

 

[blacksport]

non 4x4 i like 3.42 or 3.73.i had 3.08 stock and they were not that bad

 

[Tdean91491]

I’ve learned that mine has the g80 gov lock, most of what I’ve read and understood said you had to have special gym tools to replace the gov lock mechanisms. What would be a decent complete carrier to swap to?

 

[df2x4]

I’ve learned that mine has the g80 gov lock, most of what I’ve read and understood said you had to have special gym tools to replace the gov lock mechanisms. What would be a decent complete carrier to swap to?

Depends on what you want the truck to do, and how you want it to behave. For occasional off roading but mostly street driving I'd look into an Eaton TrueTrac. The TrueTrac is a helical gear limited slip carrier that will transfer power between wheels smoothly on the fly as long as both drive wheels have at least some traction. If one wheel loses traction completely (like if it comes off the ground) that wheel will take all the power and spin freely unless you apply some brakes to simulate traction. If that bothers you or you're looking for a more constant 50/50 lock between the drive wheels then I'd go with an Eaton Detroit Locker. The Detroit is not nearly as smooth, you'll feel it engaging and disengaging on the street. Much more durable and better off the pavement, though.

If all you're trying to do is change the gearing there's no reason you can't just re-use the factory G80, though.

 

[David Barry]

I concur with Randomguy - 4.56 ratio at a MINIMUM. The 4.88 ratio is probably the better fit, though. There is a formula to help with the numbers. (Those in the know - chime in!) I changed out the gears in my c1500, 5.7 from 3.42 to 4.10 to compensate for 31" tires. Truck runs great! I used the VSSB/DRAC calculation for my '93 to align the odometer and speedometer. [For '91 - '95s, not sure what year your truck is.]