Author Topic: rearend help..  (Read 4939 times)

Offline Lobsterbak

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rearend help..
« on: May 21, 2006, 05:08:00 pm »
Ok,

    I'm soon off to Iraq (5 weeks, yar :D ), and while Im over there my Bro/Father will be the ones working on the chev, trying to get her done before I come on home on Midtour leave.

   The next step Im taking (besides bodywork..>: ) Is replacing the rearend. Its a 10 Bolt, with 2.73 Gears..:lol , I really dont want to use those, with my 350 I'd like something better like 3.73's or even 4.10's.

   My question is, what kind of gears should I get? I've been looking at Richmond, but I wanted to ask around. Also I would like a good Locker, and new axles.

My goal is not to use junkyard parts, Im trying to build this truck using new parts, as long as the money is there, So I'm not constantly fixing it ;)  

Thanks all..
Morehouse

:eek  


Offline Lt.Del

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rearend help..
« Reply #1 on: May 21, 2006, 04:47:00 pm »
I am no expert on rearends, but you want a really low rear?

Quote:
I'd like something better like 3.73's or even 4.10's



That will drop your mpg waaaayyy down.  You will feel the horsepower at lower speeds, but my goodness, you won't pass a gas station without stopping.

I have a 3.08 rear and love it.  She'll fly on the interstate and you can still feel the power at slower speeds.

SgtDel


Offline Lobsterbak

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Re: rearend help..
« Reply #2 on: May 21, 2006, 05:32:00 pm »
Aight,

   Thats a good point, where I live in NY (waayy upstate) Gas is pushing 3.25 a gallon for 87, But If I drive half an hour south, its only like 2.98...>:  lol.

   So 3.08 would be the one I would want I guess, What about a locker and axles...:eek , Basically, I'd like to get best setup for snow, etc it snows/is muddy like 5 months out of the year, and my driveway is loonnng (1/2 mile), up a steep hill and it has curves, etc, and the Chev is only 2WD.  


Offline Lt.Del

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Re: rearend help..
« Reply #3 on: May 21, 2006, 07:51:00 pm »
It also depends if your tires are stock or not.  If you throw some giant wheels/tires on it, you'll want a lower gear like a 373--the bigger tires would convert that to a higher rear gear.  

It really depends on what kind of other driving you mostly do.  If you don't drive it far distances, the lower gear may be fine.  If you tow anything, a lower gear would be beneficial.  If it is just a daily driver and you don't race it or anything, a middle of the road 3.08 would be just fine.  

SgtDel


Offline Lobsterbak

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Re: rearend help..
« Reply #4 on: May 21, 2006, 09:55:00 pm »
My tires are gonna be stock, 15s. Never gonna tow anything, etc basically a nice show truck that will probably never work another hard day in its life. It was a farm truck, had a pretty rough life the past 20 years.  

So, 3:08's it is, but what about a Locker and Axles? what kind should I be looking for?



Thanks for the help! :D  


Offline roundedline

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Re: rearend help..
« Reply #5 on: May 22, 2006, 10:53:00 am »
You many be set on your gear ratio now, but I am just throwin in my 2 cents.

3.73 or 4.10 with a non OD tranny isn't going to be enjoyable.  With a 700R4 they will be fine, with 4.10's being less desireable.

With a non OD trans, the 3.42 are a good gear.  Not to much RPMs and still has some Omph out of the hole.  

As for a limited slip.  I typically install the Eaton Style Limited slip with Cluthes (not the Gov-loc) if I am looking for performance.  The Gov-loc is fine if you don't plan on abusing the truck (dragging or track use).
I have use Richmond gears in everything I have purchased except for the last set.  They were Yukon gears.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project


Offline SUX2BU99

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Re: rearend help..
« Reply #6 on: May 23, 2006, 03:38:00 pm »
What style of limited slip is the Gov-loc? Uses cones instead of clutch packs? I always thought the clutch packs were the weakest style of limited slip. I know with Ford 8.8s, the Mustangs got the clutch type with 28-spline axles but the trucks got 31 spline with a spring-type limited slip. Had this big S shaped spring visible in the diff. A friend of mine blew up the factory lim slip in his 83 Z28 and put an Auburn cone-type in and was happy with it.

Is there a definitive way of finding out what ratio the diff is from the housing itself? I tried jacking the truck up and doing the rotate the tire and count the number of rotations vs. one rotation of the driveshaft. With both wheels turning freely, I got 1 1/2, so I guess that would equate to about 3.08. I suppose with keeping 1 tire from turning, the other would turn approx. 3 times. And my truck seems to act like it has lim slip when I can get the tires spinning (both always seem to light up evenly if I am in a straight line) but the tires were spinning in opposite directions when I had it jacked up, indicating open diff.

85 Chevy Silverado C10 short, wide, yellow, 2wd. Lowered, 60-over 350 with Dart Iron Eagle heads and Comp Cams XE268 cam, TH350 w/ shift kit, 3.40 Gov-lok 12 bolt.

Offline roundedline

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Re: rearend help..
« Reply #7 on: May 23, 2006, 05:34:00 pm »
In my opinion, Auburn cone diffs are JUNK.  They eat the case housing.  When the go bad, they explode and usually take out everything in the rear.

The G80 Mechanical Locker isn't a limited slip.  It is a slip sensing locker.  It uses a governer flyweight and clutches.  When slip is present it locks the rear.

I could be wrong but all the 3rd gens used Auburns up until 1998 when it was replace by a Torsen diff..

The definitive way to find the gear ratio is to pull the cover and find the numbers on the ring gear and divide them.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project