How To Identify a Posi Rear end? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67Mach1 · 09-29-2007, 10:59 PM

I think one of the trucks I picked up this weekend has a Posi rear end. Mainly because the guy said it did. But , secondarily because when I turned one wheel the other wheel did not turn in the opposite direction.

This was done with both rear wheels off the ground BTW.

Now since the other wheel did not turn in the oposite direction, in fact did not turn at all does that prove or disprove anything?

Thanks,

OH it is a 12 bolt and had the following number on it 06818 stamped or molded into the center section, no tag avaliable.

sdkid · 09-29-2007, 11:33 PM

If you can still read the gove box label, that may tell you. Jack one side up. The other tire is on the ground. Try to turn the wheel. A axle with posi will not turn.

Frizzle Fry · 09-30-2007, 01:03 AM

Quote:

Originally Posted by sdkid

Jack one side up. The other tire is on the ground. Try to turn the wheel. A axle with posi will not turn.

Neither will an open diff if the driveshaft is still there and it's in gear or park... Just be sure it's either in neutral or the DS is removed

Spray-Bomb · 09-29-2007, 11:47 PM

Lemme know what you decide to do with those trucks bro !!!

jay_shy · 09-30-2007, 12:13 AM

As said before. The easiest way to tell is to pull the cover.

If its on the options sheet, there is no telling if a previous owner swaped it out.

Jason

67Mach1 · 09-30-2007, 08:43 AM

Thanks everyone for the help. THe rear end did not have the DS installed but we did it with both tires off the ground. Once I can get back out there I will either open the rear up or try to do it with one tire on the ground and see what happens.

Spraybomb: It was all I could do yesterday to get them moved and over to the farm. Which is about 1.5 hours away from where I live. Until I go over everything and figure out what I'll need, no promises on what will be up for sale.

I can tell you this most body panels are rusted out in at least one place. its the extra parts and the frames that are worth the purchase price.

corn · 09-30-2007, 12:37 AM

I agree with Jason. The SPID will tell you if the truck came with a posi but it cant tell you if its still in the truck...

**special-K** · 09-30-2007, 07:49 AM

Remove diff cover and observe the lack of spider gears/open carrier in center section,if it`s posi.

billsbowtie · 09-30-2007, 10:59 AM

sometimes they still have a tag like this on them.

billsbowtie · 09-30-2007, 11:01 AM

hears what it looks like with cover off.

EAST SIDE LOW LIFE · 09-30-2007, 06:14 PM

Look for vent tube if it is a posi it will have one. Posi lube warning tag is on the diff. plug.

**Classic Bowties** · 10-04-2007, 02:27 PM

Quote:

Originally Posted by EAST SIDE LOW LIFE

Look for vent tube if it is a posi it will have one. Posi lube warning tag is on the diff. plug.

EAST SIDE: I agree on the Lube Tag, and will add that most of the time they are missing anyway(like the last 3 posi's I pulled), so if the tag is seen/found chances are very good that you have a posi and even if the tag is not present it is still worth the time and effort taken to remove the cover to know/verify what you have for sure, you just never know what's in there after 35 plus years of service

As far as the vent tube (as per your added pic) being a indicator of a positraction and/or only being on posi axles, I wolud have to disagree. I currently have a 67, two 68's & early 70 all with narrow housing non-posi/open 6 lug 1/2 ton rear's and they all have the vent tube attached to the frame x-member or the pass. frame rail. I also have a 71 and two 72's all with wide housing non-posi/open 5 lug 1/2 ton rear's and they all have the vent tube secured above on the frame x-member. Cb

Frizzle Fry · 10-04-2007, 04:12 PM

Quote:

Originally Posted by Classic Bowties

EAST SIDE: I agree on the Lube Tag, and will add that most of the time they are missing anyway(like the last 3 posi's I pulled), so if the tag is seen/found chances are very good that you have a posi and even if the tag is not present it is still worth the time and effort taken to remove the cover to know/verify what you have for sure, you just never know what's in there after 35 plus years of service

As far as the vent tube (as per your added pic) being a indicator of a positraction and/or only being on posi axles, I wolud have to disagree. I currently have a 67, two 68's & early 70 all with narrow housing non-posi/open 6 lug 1/2 ton rear's and they all have the vent tube attached to the frame x-member or the pass. frame rail. I also have a 71 and two 72's all with wide housing non-posi/open 5 lug 1/2 ton rear's and they all have the vent tube secured above on the frame x-member. Cb

My open diff rear has a vent tube.

EAST SIDE LOW LIFE · 10-04-2007, 04:54 PM

Most times I turn one wheel after jacking the vehicle up and blocking the other wheel and this usually is a good indicator. I guess it doesn't work in all cases as one member has stated. Most rear ends are vented. I thought non posi rear ends used a breather vent and posi's used a tube. I have a 50, 60, 70 all posi rear ends with vent tubes. All three of them the covers have been pulled and were posi's. I guess to be sure one must pull the cover!

esll.

Picture of breather vent that has pop up and no tube. I always thought these were used as vents on non posi's.

billsbowtie · 09-30-2007, 07:19 PM

east side do the non pois. rears have a vent tube also? my project truck has a vent tube and i am almost sure its not pois. yet.

EAST SIDE LOW LIFE · 09-30-2007, 08:13 PM

Quote:

Originally Posted by billsbowtie

east side do the non pois. rears have a vent tube also? my project truck has a vent tube and i am almost sure its not pois. yet.

**********************************************************

They have a breather tube with a cap on the top. I don't have a picture or I would post it. This can be found on google. You can jack up your frame and spin one tire if posi both will turn.

esll.

68caliRat · 10-01-2007, 08:28 PM

Vent on a posi? I have a Dana 60 with posi(stock) and there's no vent tube. I'm not doubting that they may have had them on some, but mine didn't.

EAST SIDE LOW LIFE · 10-04-2007, 12:56 PM

Here is a picture of a vent tube on a 1960 Vette rear end. It's the metal tube that is attached to the diff. housing and looks like it's going no where.

esll.

Tha Dana rear end I cannot say what the deal is there. But if it is factory that way that does not mean that is the case for all posi's.

Scott68-93-97 · 10-04-2007, 01:58 PM

Best way to tell is hold your foot to the floor and get out and view the marks

or pull the cover, the wheel spinning deal doesn't always work, excpecially with a gov lock or tosion lockers, both have a similar locking mechanisms that sense a difference in rotation and lock up, like on my 97 its open if you turn the wheel very slow opposite side turns opposite but when you quickly turn the one side it locks in and both turn the same direction and it stays locked until theres more force on one side like when you go around a turn, it will also lock in if you apply power. The gov locks you will know if you have one you can actually here them lock up there common on 4x4's

LUV2XCLR8 · 10-04-2007, 06:02 PM

May have to try that one up / one down / neutral / spinthingy test

09-29-2007, 10:59 PM	#1
67Mach1 Senior Member Join Date: Nov 2005 Location: Round Rock, TX Posts: 1,100	How To Identify a Posi Rear end? I think one of the trucks I picked up this weekend has a Posi rear end. Mainly because the guy said it did. But , secondarily because when I turned one wheel the other wheel did not turn in the opposite direction. This was done with both rear wheels off the ground BTW. Now since the other wheel did not turn in the oposite direction, in fact did not turn at all does that prove or disprove anything? Thanks, OH it is a 12 bolt and had the following number on it 06818 stamped or molded into the center section, no tag avaliable. __________________ Soon to be selling all but one, or two... Depends on what the Boss has to say....... 67 GMC Shortbed 454 Project more junk and most of it is for sale Last edited by 67Mach1; 09-29-2007 at 11:20 PM.

09-29-2007, 11:33 PM	#2
sdkid Registered User Join Date: Sep 2004 Location: Pierre SD Posts: 1,533	Re: How To Identify a Posi Rear end? If you can still read the gove box label, that may tell you. Jack one side up. The other tire is on the ground. Try to turn the wheel. A axle with posi will not turn. __________________ I think the world needs a drink... Help somebody...If you can....VanZant We're not wrong, we're not sorry, and its probably gonna happen again. That's the truth about men. Tracy Byrd Member# 13924 '70 c10, 350/350 '68 c10 250/4spd '68 c10 no eng/trans fac ps/pb/ac/at (future father/sons project) '48 Chevy Loadmaster

09-29-2007, 11:47 PM	#4
Spray-Bomb Texas Big Wig Join Date: Jan 2007 Location: Mineola, Texas Posts: 5,620	Re: How To Identify a Posi Rear end? Lemme know what you decide to do with those trucks bro !!! __________________ Just not low enough... ----------------------------- Sinister Killer

09-30-2007, 12:13 AM	#5
jay_shy SWB 4X4 CLUB Join Date: Feb 2005 Location: PA Posts: 1,088	Re: How To Identify a Posi Rear end? As said before. The easiest way to tell is to pull the cover. If its on the options sheet, there is no telling if a previous owner swaped it out. Jason

09-30-2007, 08:43 AM	#6
67Mach1 Senior Member Join Date: Nov 2005 Location: Round Rock, TX Posts: 1,100	Re: How To Identify a Posi Rear end? Thanks everyone for the help. THe rear end did not have the DS installed but we did it with both tires off the ground. Once I can get back out there I will either open the rear up or try to do it with one tire on the ground and see what happens. Spraybomb: It was all I could do yesterday to get them moved and over to the farm. Which is about 1.5 hours away from where I live. Until I go over everything and figure out what I'll need, no promises on what will be up for sale. I can tell you this most body panels are rusted out in at least one place. its the extra parts and the frames that are worth the purchase price. __________________ Soon to be selling all but one, or two... Depends on what the Boss has to say....... 67 GMC Shortbed 454 Project more junk and most of it is for sale Last edited by 67Mach1; 09-30-2007 at 02:27 PM.

09-30-2007, 12:37 AM	#7
corn Registered User Join Date: Dec 2003 Location: here Posts: 5,789	Re: How To Identify a Posi Rear end? I agree with Jason. The SPID will tell you if the truck came with a posi but it cant tell you if its still in the truck...

09-30-2007, 07:49 AM	#8
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: How To Identify a Posi Rear end? Remove diff cover and observe the lack of spider gears/open carrier in center section,if it`s posi. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

09-30-2007, 10:59 AM	#9
billsbowtie Senior Member Join Date: Feb 2003 Location: rose hill V.A. 24281 Posts: 17,997	Re: How To Identify a Posi Rear end? sometimes they still have a tag like this on them. __________________ i have 67/72 chevy truck parts f/s.

09-30-2007, 11:01 AM	#10
billsbowtie Senior Member Join Date: Feb 2003 Location: rose hill V.A. 24281 Posts: 17,997	Re: How To Identify a Posi Rear end? hears what it looks like with cover off. __________________ i have 67/72 chevy truck parts f/s.

09-30-2007, 06:14 PM	#11
EAST SIDE LOW LIFE Senior Member Join Date: Mar 2007 Location: VANCOUVER ISLAND, B.C., Canada Posts: 1,602	Re: How To Identify a Posi Rear end? *Look for vent tube if it is a posi it will have one. Posi lube warning tag is on the diff. plug.* Attached Images __________________ Tomorrow is for doing today's stuff. ************************************* This truck has just the right amount of energy for me! Author: Warren Lake .... (member)

10-04-2007, 04:54 PM	#14
EAST SIDE LOW LIFE Senior Member Join Date: Mar 2007 Location: VANCOUVER ISLAND, B.C., Canada Posts: 1,602	Re: How To Identify a Posi Rear end? Most times I turn one wheel after jacking the vehicle up and blocking the other wheel and this usually is a good indicator. I guess it doesn't work in all cases as one member has stated. Most rear ends are vented. I thought non posi rear ends used a breather vent and posi's used a tube. I have a 50, 60, 70 all posi rear ends with vent tubes. All three of them the covers have been pulled and were posi's. I guess to be sure one must pull the cover! esll. Picture of breather vent that has pop up and no tube. I always thought these were used as vents on non posi's. Attached Images __________________ Tomorrow is for doing today's stuff. ************************************* This truck has just the right amount of energy for me! Author: Warren Lake .... (member) Last edited by EAST SIDE LOW LIFE; 10-04-2007 at 04:56 PM.

09-30-2007, 07:19 PM	#15
billsbowtie Senior Member Join Date: Feb 2003 Location: rose hill V.A. 24281 Posts: 17,997	Re: How To Identify a Posi Rear end? east side do the non pois. rears have a vent tube also? my project truck has a vent tube and i am almost sure its not pois. yet. __________________ i have 67/72 chevy truck parts f/s.

10-01-2007, 08:28 PM	#17
68caliRat Need a bigger hammer.. Join Date: Feb 2007 Location: Escondido,CA. Posts: 280	Re: How To Identify a Posi Rear end? Vent on a posi? I have a Dana 60 with posi(stock) and there's no vent tube. I'm not doubting that they may have had them on some, but mine didn't. __________________ 1968 GMC 3/4 LWB fleetside Custom Camper 2018 Silverado High Country 2500HD Duramax 4X4

10-04-2007, 12:56 PM	#18
EAST SIDE LOW LIFE Senior Member Join Date: Mar 2007 Location: VANCOUVER ISLAND, B.C., Canada Posts: 1,602	Re: How To Identify a Posi Rear end? Here is a picture of a vent tube on a 1960 Vette rear end. It's the metal tube that is attached to the diff. housing and looks like it's going no where. esll. Tha Dana rear end I cannot say what the deal is there. But if it is factory that way that does not mean that is the case for all posi's. Attached Images __________________ Tomorrow is for doing today's stuff. ************************************* This truck has just the right amount of energy for me! Author: Warren Lake .... (member)

10-04-2007, 01:58 PM	#19
Scott68-93-97 Registered User Join Date: Jul 2006 Location: Fair Oaks, CA Posts: 475	Re: How To Identify a Posi Rear end? Best way to tell is hold your foot to the floor and get out and view the marks or pull the cover, the wheel spinning deal doesn't always work, excpecially with a gov lock or tosion lockers, both have a similar locking mechanisms that sense a difference in rotation and lock up, like on my 97 its open if you turn the wheel very slow opposite side turns opposite but when you quickly turn the one side it locks in and both turn the same direction and it stays locked until theres more force on one side like when you go around a turn, it will also lock in if you apply power. The gov locks you will know if you have one you can actually here them lock up there common on 4x4's __________________ 1968 Short Fleet 350/700r4 http://67-72chevytrucks.com/vboard/s...d.php?t=249435 1997 Bagged XtdCab Vortec350/4L60e http://67-72chevytrucks.com/vboard/s...44#post2286144 1993 XtdCab Longbed 4x4 6.5Turbo/NV4500 "Daily Driver" 1985 Toyota XtdCab 4x4 22re/W-56/Dual T-cases, Doug Thorley Header, Homebrew front and rear spring packs, Tons of Mods to suspension and drivetrain, 35" boggers, coming soon ARB's and 5.29's, Possible 4.3/700r4 swap



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10-04-2007, 06:02 PM	#20
LUV2XCLR8 The LuvShack Garage Join Date: Jan 2004 Location: Maple Grove, TN (West Side) Posts: 30,468	Re: How To Identify a Posi Rear end? May have to try that one up / one down / neutral / spinthingy test __________________ Owner/Op: "TN Classic Transport Carriers" The Toy: "Square Vette" 72 Hybrid Blazer Toy Barn: "LuvShack" 40 x 60 x 20 Shop Tow Piggy:"Maddy" 88 Silverado 3500 Hauler: "Feathers" 14 Aluma 8218T

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