Rear End

[stingray72]

Need a new rear end now that my swap is done. What do you guys recommend? Right now running something really high(?) like 3:07s. Thinking of going lower like 3:56 or something but I dumb when it comes to this stuff

Suggestions? Not a power monster, just a driver but not overly concerned with Gas mileage etc

[crazy longhorn]

With an OD trans, 3.73 gears will be (IMO), just about perfect. Without the OD, I like a 3.42 gear (best all around power /mileage). crazyL

[stingray72]

Oh ya forgot to mention. 4L60E transmission and I was leaning towards 3:73

[mooseknuckles]

I'm runnin a 3:42 which is just about the perfect gear.....3:73's may be too low if you drive it daily.....I had 3:08's in mine it was fun to drive!, just a little too fast...might try a set of 3:23's later on.

[crazy longhorn]

With the .7 OD, you could probably go either way on the gear(3.42 or 3.73)....it does depend a bit on tire size tho I run a 3.42's in my truck, on a 29" tire. OD is .76, & it works good, but I feel that I would be happier with the 3.73 gears. With a shorter tire, the 3.42's may work better for you. What you might do is try a couple gear/ speed calculators, & see what it takes to drop your hyway cruise into the rpm band that you want to run best of fun,crazyL

[68GMCCustom]

with a overdrive - 3.73 - 4.11 or higher

w/o overdrive 3.23 - 3.55 or lower


with 3.73's my truck was turning 3k or higher on the freeway. not fun over long distances

[stingray72]

Sorry, more questions

Am I better off buying gears and having someone install them for me? I also want posi which I don't have right now

[68GMCCustom]

if you don't have the tools or the experience....pay someone else to do it for you. unless you're wanting to learn of course...

[stingray72]

Originally Posted by 68GMCCustom

if you don't have the tools or the experience....pay someone else to do it for you. unless you're wanting to learn of course...

I don't have the space so I will certainly be paying someone. Just didn't know what was involved or what to look for.

Leaning towards a rebuild/new just to (hopefully) have it done correctly but didn't know everything that would be involved changing the gear ratio and adding posi

[68GMCCustom]

I had a 3.08 one legger 12 bolt...had a rebuild done w/Eaton posi added and gears changed to 3.73's...cost me $1050 I think. Thats probably $300-$400 labor or so?

[CigarMan]

I just bought everything needed to change 3.08 to 3.73 posi with master bearing kit from National drivetrain. $655 to the door

[mooseknuckles]

you can def save yourself some money if you can do it yourself!.....there are a few tricks to set it up, but it's pretty basic.

[BR3W CITY]

3;73 in my 12 bolt, seems like about the perfect amount of rear. Anything less, and turning the big rear meat would be a pain.

While doing rear gears isn't really "hard" I might advise against it if you haven't done it before, or don't have a helping hand who has. Especially with gears like Motives, if the lash isn't setup right (sometimes even if it seams dead on) your rear will WHINE. Eventually it will marr the gears. Not trying to scare you, just sometimes when you try to save money...you spend more in the long run.

[stingray72]

I'm going to pay someone, just have to find the right person and make sure I'm getting what I want

[chevy72blu]

I spent a summer working at a driveline shop trying to learn the art of installing gears... I picked up a lot of tips, but there really is an art to setting lash PERFECTLY. You can get er done, but the question is low long it will last. A huge majority of our customers were folks that installed their own R&P sets/lockers and brought them in a few months later.

My biggest take away from the experience was to hire that shop for my future needs. I dont like to admit my own shortcomings, but its just one of those things thats not for me.


3.73's were probably the most popular gear for a 28" tire and an OD trans in hotrod/cruiser vehicles if that tells you anything.

[crazy longhorn]

Any shop will tell you, but just for a little info....2.76-3.42 gears run on a 3 series carrier. 3.73/ 4.10 /4.56, gears,ect... fit a 4 series carrier. IMO, the best thing to do is talk with the shop setting the gears up & ask their opinion on what works & runs quiet best of fun,crazyL