4.10 vs. 3.73, general gear questions (long)
Oct 24, 2004 | 11:48 AM
#13
Originally Posted by DUNGBEETLE
Well the part I order for my 2003 silverado 5.3 was the 8.5 and thats after i called a Chevy dealership, Im not saying your wrong but the 2003 is definently a 8.5 10 bolt
Oct 24, 2004 | 12:13 PM
#14
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From: Salt Lake City, Utah
Originally Posted by Naked AV
Alright, I've received some advice that to get some more power (that I can feel, since I don't want to swap out the converter), I should consider 4.10 gears instead of my stock 3.73's. Problem is, I don't know anything about gears. 
I've done some searching and reading, but I've been coming up short in the knowledge arena. So I need some help.
One of the things I seem to read is that the actual 'gears' are different from the other stuff (G80 limited slip, Eaton posi, etc.). Is this the case? Is gear replacement different from a posi installation or replacement? Are these two different things? If so, does that mean I can replace my 3.73 gears with 4.10 gears, and leave the G80 part? What brands of gears are good?
The other thing I am concerned with is strength. I've heard that the stock G80 is weak....is that true? If so, do I need to put something else in when I do the gears? If so, what should go in there? I've also heard that a good aftermarket cover made out of stainless or aluminum will go a long way toward keep the rear end together. Is this true?
I've also heard that not just anyone can do gears, that it's a delicate operation and it can be screwed up pretty easily. Is this the case? If so, what should I watch out for when it comes to looking for a shop? There's ORW and 4 Wheel Parts around here, I'm wondering if they would be good places to check out.
I've done some searching and reading, but I've been coming up short in the knowledge arena. So I need some help.One of the things I seem to read is that the actual 'gears' are different from the other stuff (G80 limited slip, Eaton posi, etc.). Is this the case? Is gear replacement different from a posi installation or replacement? Are these two different things? If so, does that mean I can replace my 3.73 gears with 4.10 gears, and leave the G80 part? What brands of gears are good?
The other thing I am concerned with is strength. I've heard that the stock G80 is weak....is that true? If so, do I need to put something else in when I do the gears? If so, what should go in there? I've also heard that a good aftermarket cover made out of stainless or aluminum will go a long way toward keep the rear end together. Is this true?
I've also heard that not just anyone can do gears, that it's a delicate operation and it can be screwed up pretty easily. Is this the case? If so, what should I watch out for when it comes to looking for a shop? There's ORW and 4 Wheel Parts around here, I'm wondering if they would be good places to check out.
Oct 24, 2004 | 12:31 PM
#15
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From: Sun Diego
Originally Posted by Black Blown 02
Naked, I think youll be dissapointed going from 3.73 to 4.10. I test drove 2 identical trucks before I bought mine. The only difference was one had 3.73's and one had 4.10's. I could BARELY tell a difference. IMO it wouldn't be worth the hassle. I'll bet the swap would only be worth 1-2 tenths at the track.
Oct 24, 2004 | 01:58 PM
#17
As of yesterday I can say there is a great improvement with 4.10's over my old 3.73's.
I could definetly tell the difference. Now, that being said, I wouldn't call it night and day, just that the engine/tranny seemed to like the 4.10's a whole lot better and that everything seemed right! nothing straining to do its job. I think its probably just about as steep as you'd want to go on the street unless your running much bigger tires than stock. With my stock 31" (nominal) tires the 4.10's were noticable over my previous 3.73's. Just my experiences here folks.
I could definetly tell the difference. Now, that being said, I wouldn't call it night and day, just that the engine/tranny seemed to like the 4.10's a whole lot better and that everything seemed right! nothing straining to do its job. I think its probably just about as steep as you'd want to go on the street unless your running much bigger tires than stock. With my stock 31" (nominal) tires the 4.10's were noticable over my previous 3.73's. Just my experiences here folks.
Oct 24, 2004 | 02:07 PM
#18
Originally Posted by DUNGBEETLE
Well the part I order for my 2003 silverado 5.3 was the 8.5 and thats after i called a Chevy dealership, Im not saying your wrong but the 2003 is definently a 8.5 10 bolt
Oct 24, 2004 | 03:50 PM
#19
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From: Cali
Originally Posted by moregrip
The 1/2 ton rear diff very well might be an 8.5. I was just putting out that info so Naked might not order incorrect gears. I thought AAM provided GM all their axles so maybe this one is different or maybe it is an 8.6", just commonly called the 8.5". Either way I'd like to know for sure just out of curiousity.
Ive been told both the 8.5 and 8.6 ring and pinoins will work in our trucks.
Oct 24, 2004 | 04:20 PM
#20
I just got my rear done, and the shop said an 8.5/8.6 will work. Our rear-ends are essentially the same as a typical 8.5 30spline, just with a few internal differences. I know the carrier is different for 99-up 10bolts, but the ring gears are interchangeable. I would get the 8.5" gear, because you don't see too many 8.6" gears available 
I switched from 3.73's to 4.56's and I felt a very noticable difference. I run a tall tire, and the truck moves a hell of a lot easier now. It pulls harder and 2nd gear is not nearly as lame.
No noticable change in mpg in town either.
I switched from 3.73's to 4.56's and I felt a very noticable difference. I run a tall tire, and the truck moves a hell of a lot easier now. It pulls harder and 2nd gear is not nearly as lame.
No noticable change in mpg in town either.
