Gear compatibility

[dhamp]

Thinking of dumping my old stock 2.73 open diff gears. A buddy of mine has some 3.23s out of a 2007 Silverado w/posi that he's getting rid of. Anyone know if they'll work with my axle??

 

[Sasquatch]

What year is your truck? what axles do you have?

 

[tanz45]

10 bolt 8.5 and 8.6 (new chevy 99 and up) gears should swap.

Carrier bearings are just different sizes.

But having stock 2.73, don't you have that goofy carrier that would require the spacer?

 

[HotRodPC]

Welcome dhamp. What year is your truck? What model is it? C10, K20 etc??? We can sure help you out if we know what you're working on.

 

[dhamp]

More info

Duh! I left all the info out, huh? Sorry about that. My truck is an '87 R10 bone stock w/a 350 and 2WD. It's got a 10-bolt 8.5 w/open diff. I'm not 100% sure, but I think they used the the 2 different carries (split at 3.73) until '78 then they were all the same for open diffs, but a different one for posi or LSD. Like I said, not 100% sure though. That's what replacement parts codes indicate via LMC.

 

[HotRodPC]

In my honest opinioin dhamp, I wouldn't be interested in your buddies set up. For 1, the 3.23 is some change, but its minimal. Although, it might be right where you want to be. Its only half a turn and 3.23 is still pretty tall. Personally I like the 3.42 gear for a 1/2 ton 2wd pick up. The other thing is, unless he had it upgraded aftermarket, his posi isn't really a posi. Its a G80 Eaton Gov-Lock if its factory. About all its good for is pulling a boat up a wet boat ramp. Past that, its not all that good of unit. The Gov gear loves to strip out on those units, and those units are only good for about 25mph and less. IMO, if you want a posi unit, I'd find me a good used 3.42 or 3.73 rear end, either 10 bolt or 12 bolt. Then add a Lock Right Locker unit to the open differential, simply by removing the spider gears and installing the Lock Right unit in their place. If you like that 2.73 ratio you currently have, and its open diff, then just buy the Lock Right and install in what you have now.

 

[dhamp]

Thanks HotRodPC. Good thinking. Actually, he's keeping the posi in the truck. He was just selling the gear. I really don't have a problem w/the current setup to be honest. I didn't want to change the rear too much to where it's drinking even more gas than it's drinking now. I do plan to do some short 1hr highway runs in it from time to time, and I don't want it revving high and sucking fuel excessively. I value the mid- and high-range pull a little more than off-the-line romps. It'll barely launch w/out spinning as is!

 

[HotRodPC]

I think what some people forget, is a tall gear doesn't always mean better fuel mpg. I am certain my C20 with 3.21 gears in the rear would do better around town if I had 4.10's. Remember with a tall gear, its takes more umph to get it rolling. The ultimate set up is a low rear gear like 3.73 - 4.56 with an overdrive trans.

 

[dhamp]

Good point HotRodPC. I guess it really depends on your driving habits/conditions. I could see have the higher numerical ratios helping out with in-town driving since you can use less throttle and let the tranny gears get you going. I don't drive it in much of that. It's mostly state routes to work where I may hit 3 lights in 20 miles.

 

[HotRodPC]

Good point HotRodPC. I guess it really depends on your driving habits/conditions. I could see have the higher numerical ratios helping out with in-town driving since you can use less throttle and let the tranny gears get you going. I don't drive it in much of that. It's mostly state routes to work where I may hit 3 lights in 20 miles.

So you actually benefit from the taller gear ratio then. No need to spend the cash on what's working well. If its not broke, don't fix it as the saying goes.

 

[89Suburban]

 

[dhamp]

Good call HotRodPC. I'll sit that money back and use it when I'm ready to get a locker installed.

 

[89Suburban]

Another happy customer!

 

[Old77]

another happy customer! :d

1-800-555-gmsb

 

[HotRodPC]

Good call HotRodPC. I'll sit that money back and use it when I'm ready to get a locker installed.

You know, if you aren't running over 350hp, or a real big tire, you can probably get by with a Lock Right unit. I've heard of 2 people that installed them themselves and still using them to this day and working great. Inexpensive, and you can likley install it yourself in your driveway on a nice warm Saturday. I been told it takes about an hour, then I been told, don't be fooled it takes more like 3 hours. So either way, even if it took half the day, you can do it yourself, and not have to pay $600-$700 to have a Locker installed. I have not got to do one yet myself, but I will be when things get better. Basically, you pull your rear cover, slide the axles out, pull your spiders gears out, install this unit in place of your spiders, put the axles back in, cover back on, Fill with gear oil and done. No resetting up of the ring and pinion, no special tools required. Even a cave man can do it.

Here is a little info about the Lock Right. And this place here, rocky-road has the unit I need cheaper than anyone else, so I keep it bookmarked.
http://www.rocky-road.com/lockright.html