How do you identify posi rear end - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**FL71C10** · 06-24-2010, 06:33 AM

How do I tell if my rear end has positraction?

My spid label is missing.

kacz81 · 06-24-2010, 07:09 AM

Use a floor jack to get both rear tires off the ground and spin one tire if both rear tires move foward you have posi if one tire moves forward and backward you have one tire fire

**FL71C10** · 06-24-2010, 07:52 AM

Thanks!

cdowns · 06-24-2010, 08:34 AM

from factory at the fill hole there is a plastic tag on it saying its posi

a good thing is to pull cover drain clean and freash clean new gear lube and at that time u can tell 4 sure

raycow · 06-24-2010, 02:34 PM

Jack one rear wheel off the ground. Put the transmission in neutral and the parking brake off. Now try to turn the wheel. If you have posi in working condition, the wheel will be difficult or impossible to turn. If it turns easily, you have an open rear or a dead posi.

Ray

67ChevyRedneck · 06-24-2010, 02:47 PM

Stomp on the go pedal and see how many black streaks are left behind

Number98 · 06-24-2010, 03:13 PM

Quote:

Originally Posted by 67ChevyRedneck

Stomp on the go pedal and see how many black streaks are left behind

This test gets my vote....

68longhorn · 06-24-2010, 06:44 PM

agree with above, its the most fun. But the best way is to take the cover off and look for clutches.

tonypaul · 06-24-2010, 07:10 PM

Take off the cover to find out for sure... Unless you have a full spool, both wheels may not nessarly spin with the tires in the air method. If you have a limited slip diff, it takes one tire to start to spin and then the clutches ingage and then both start to spin. "Posi" is a word that get threw around alot, I would recommend doing some research on your truck and maybe on the internet to truey idenify what type of diff you have...

**FL71C10** · 06-24-2010, 07:32 PM

Does someone have a picture of a posi gear set vs a regular gear set? Do I just take off the back cover?

Thanks!

trusty72 · 06-24-2010, 10:30 PM

open diff will be the ring gear with 2 small spiders gears and a pin thru the middle, posi with be encased with no gears showing other than the ring and pinion

LONGHAIR · 06-25-2010, 06:58 AM

Quote:

Originally Posted by trusty72

open diff will be the ring gear with 2 small spiders gears and a pin thru the middle, posi with be encased with no gears showing other than the ring and pinion

In what kind of rear end?...I don't know of any factory 1/2 ton like that...

A Detroit Locker or a Gov-Lock for a 14 bolt FF, yes...but you are going to see spider gears in a 1/2 ton "Posi" too, there will be springs between them, but you can still see them.

LostMy65 · 01-06-2011, 11:14 PM

Quote:

Originally Posted by 67ChevyRedneck

Stomp on the go pedal and see how many black streaks are left behind

You bring back memories of a funny mishap I had when I just got my old 65 back up and running.
I didn't know I had a posi or limited slip. - It was a new rear-end.
Also just put a new high perform 327 in it.

My brother in law helped me get it all back together and his shop.
Just fired it up, and it had such a cool lope.
It didn't have an air filter, he said he might have one that would fit out back behind his shop. Yep it fit.

So I backed out of his driveway to take it for a spin, and he hand signaled for me to peal-out.
I knew this truck pretty well, and knew I could start off in second with the rpms up. So I revved it up and dropped the clutch.
I pealed off screaming down this little neighborhood street, smoke roaring out from under the fenders. Honestly, I was pretty much holding on. The throttle got stuck open. I had to shut the key off because it was screaming wide open. People came out of their houses. A burnt rubber smelling cloud slowly drifted away. As it cleared up, I could see two wide squirrely black stripes all the way back to his house. They didn't wash away for many months.

Navy Mechanic · 01-06-2011, 11:25 PM

Quote:

Originally Posted by 67ChevyRedneck

Stomp on the go pedal and see how many black streaks are left behind

This is definitely the preferred method!

jakeblues652 · 01-06-2011, 11:30 PM

Quote:

Originally Posted by 67ChevyRedneck

Stomp on the go pedal and see how many black streaks are left behind

just make sure you look in the mirrors and make sure theres no cars with pretty lights behind you

**Hart_Rod** · 01-06-2011, 11:37 PM

Quote:

Originally Posted by FL71C10

Does someone have a picture of a posi gear set vs a regular gear set? Do I just take off the back cover?

Thanks!

Eaton posi pictures...

Christian Car · 08-02-2019, 11:31 PM

Quote:

Originally Posted by 67ChevyRedneck

Stomp on the go pedal and see how many black streaks are left behind

I tried this on my 72 Chevy c10 a few times. I sometimes left one track (right tire) and other times I left two tracks. When I left two tracks, the left track was very faint. what does this mean? I have no tag on my diff. Please help. Thank you.

06-24-2010, 06:33 AM	#1
FL71C10 Senior Member Join Date: Jun 2010 Location: Orlando, Florida Posts: 2,510	How do you identify posi rear end How do I tell if my rear end has positraction? My spid label is missing. __________________ 71 Chevy C10 Shortbed Stepside. LT1 with 4l60E. Just got back from painter, in assembly now. Last edited by FL71C10; 06-24-2010 at 06:33 AM.

06-24-2010, 07:09 AM	#2
kacz81 Registered User Join Date: Jul 2009 Location: Shorewood,IL. Posts: 75	Re: How do you identify posi rear end Use a floor jack to get both rear tires off the ground and spin one tire if both rear tires move foward you have posi if one tire moves forward and backward you have one tire fire

06-24-2010, 07:52 AM	#3
FL71C10 Senior Member Join Date: Jun 2010 Location: Orlando, Florida Posts: 2,510	Re: How do you identify posi rear end Thanks! __________________ 71 Chevy C10 Shortbed Stepside. LT1 with 4l60E. Just got back from painter, in assembly now.

06-24-2010, 08:34 AM	#4
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: How do you identify posi rear end from factory at the fill hole there is a plastic tag on it saying its posi a good thing is to pull cover drain clean and freash clean new gear lube and at that time u can tell 4 sure __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY Last edited by cdowns; 06-24-2010 at 08:35 AM.

06-24-2010, 02:34 PM	#5
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: How do you identify posi rear end Jack one rear wheel off the ground. Put the transmission in neutral and the parking brake off. Now try to turn the wheel. If you have posi in working condition, the wheel will be difficult or impossible to turn. If it turns easily, you have an open rear or a dead posi. Ray

06-24-2010, 02:47 PM	#6
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: How do you identify posi rear end Stomp on the go pedal and see how many black streaks are left behind __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

06-24-2010, 06:44 PM	#8
68longhorn Registered User Join Date: Jun 2007 Location: Cape Coral, Florida Posts: 1,123	Re: How do you identify posi rear end agree with above, its the most fun. But the best way is to take the cover off and look for clutches.

06-24-2010, 07:10 PM	#9
tonypaul Registered User Join Date: Nov 2009 Location: Austin Tx Posts: 639	Re: How do you identify posi rear end Take off the cover to find out for sure... Unless you have a full spool, both wheels may not nessarly spin with the tires in the air method. If you have a limited slip diff, it takes one tire to start to spin and then the clutches ingage and then both start to spin. "Posi" is a word that get threw around alot, I would recommend doing some research on your truck and maybe on the internet to truey idenify what type of diff you have...

06-24-2010, 07:32 PM	#10
FL71C10 Senior Member Join Date: Jun 2010 Location: Orlando, Florida Posts: 2,510	Re: How do you identify posi rear end Does someone have a picture of a posi gear set vs a regular gear set? Do I just take off the back cover? Thanks! __________________ 71 Chevy C10 Shortbed Stepside. LT1 with 4l60E. Just got back from painter, in assembly now.

06-24-2010, 10:30 PM	#11
trusty72 Registered User Join Date: May 2010 Location: ft smith arkansas Posts: 131	Re: How do you identify posi rear end open diff will be the ring gear with 2 small spiders gears and a pin thru the middle, posi with be encased with no gears showing other than the ring and pinion __________________ 1972 super cheyenne 1970 Suburb



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