Posi rear axle question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Farmstore34 · 03-21-2008, 01:40 AM

Hey all,
I'm not 100% sure, but I think the positrac quit working in my truck. Its a 1972 K20, 350, 4 speed, and the original rear axle (GM Corporate?). From what I can tell only the right rear is spinning while going forward. Are there replaceable clutches inside? Thanks,
Colby.

**special-K** · 03-21-2008, 02:59 AM

No clutches at all.It would be a locker,not a posi,if it`s factory.Does the right side spin all the time,like a live axle?(go cart)

Farmstore34 · 03-21-2008, 06:53 AM

yes it seems to be working just like a standard axle. I think the left side kicks in occasionally but it is mostly being driven by the right side.

texanidiot25 · 03-21-2008, 07:02 AM

Jack up the rear end off the ground. And put the trans in N.

Spin one tire. If they both spin together and spin the driveshaft, the posi is working (in theory). If the other tire spins in the opposite direction, no posi action.

Either that, or jack (no stands) the passenger side tire off the ground, leaving the drives side on the ground. Put it into gear, and just let out the brake slowly. If the car starts to pull the jack with it, posi is good. If not, the tire in the air will just spin along. Sorta the more dangerous way, but the for sure way.

**PICKMUP** · 03-21-2008, 07:05 AM

That is exactly what a posi does when the clutches wear out. It acts just like an open rear.
I just sent my carrier to Randy's Ring & Pinion and had them replace the clutch pack. It is tight now and even chirps the inside tire on corners, if you get on it.

slammed1 · 03-21-2008, 07:20 AM

It does sound as if your posi is toasted. Parts readily available and unless your confident in your tools and work,I would have another person build it if needed.I had one in a 67 Impala get week and I could jack it up and rotate one rear wheel with my hand and the other wheel would spin completely opposite,just like an open but I knew 110% it was posi. The rear was rebuilt and is doing time in our Drag/Street Race 68 Impala now.

**PICKMUP** · 03-21-2008, 07:53 AM

Here is one I pulled today. It spun like an open. There was no indication it was posi except listing on the SPID.

**67 cst swb** · 03-21-2008, 08:29 AM

So, what does it cost to have a posi clutch pack replaced at Randy's?

Mint68 · 03-21-2008, 11:28 AM

I thought mine acted wierd when on jack stands, but on the ground it will leave two marks, and likes to slide either way in the snow. I was going to have mine rebuilt, but I was told it was a non rebuildable unit. Seems mine has cones not cluthes.

**special-K** · 03-21-2008, 01:41 PM

In the HO52,if that`s what you actually have,only the NoSpin/Detroit Locker came from factory.No clutches,not a posi.If it has a Dana60 it could have the PowerLock posi.
I had a problem with a NoSpin where only one wheel spun full-time,like a live axle.It was worse than an open rear because I got nothing from one side and full power all the time to the other.Believe me,if you`ve ever had this you`d realize how nice a bias open rear operates.With one wheel under power at all times you can`t back up a stone incline.It`s like a go cart.The only think I could figure was a weak side spring.But,I couldn`t see anything wrong.I just put another unit in that I had.

03-21-2008, 01:40 AM	#1
Farmstore34 Registered User Join Date: Mar 2007 Location: Oregon Posts: 109	Posi rear axle question Hey all, I'm not 100% sure, but I think the positrac quit working in my truck. Its a 1972 K20, 350, 4 speed, and the original rear axle (GM Corporate?). From what I can tell only the right rear is spinning while going forward. Are there replaceable clutches inside? Thanks, Colby.

03-21-2008, 02:59 AM	#2
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Posi rear axle question No clutches at all.It would be a locker,not a posi,if it`s factory.Does the right side spin all the time,like a live axle?(go cart) __________________ "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 ~ Last edited by special-K; 03-21-2008 at 03:01 AM.

03-21-2008, 06:53 AM	#3
Farmstore34 Registered User Join Date: Mar 2007 Location: Oregon Posts: 109	Re: Posi rear axle question yes it seems to be working just like a standard axle. I think the left side kicks in occasionally but it is mostly being driven by the right side.

03-21-2008, 07:02 AM	#4
texanidiot25 Eat My Rust Join Date: Jan 2007 Location: Cypress, Texas Posts: 3,362	Re: Posi rear axle question Jack up the rear end off the ground. And put the trans in N. Spin one tire. If they both spin together and spin the driveshaft, the posi is working (in theory). If the other tire spins in the opposite direction, no posi action. Either that, or jack (no stands) the passenger side tire off the ground, leaving the drives side on the ground. Put it into gear, and just let out the brake slowly. If the car starts to pull the jack with it, posi is good. If not, the tire in the air will just spin along. Sorta the more dangerous way, but the for sure way.

03-21-2008, 07:05 AM	#5
PICKMUP "Trucks with Class" Join Date: Jul 2000 Location: OLYMPIA, WA, USA Posts: 8,158	Re: Posi rear axle question That is exactly what a posi does when the clutches wear out. It acts just like an open rear. I just sent my carrier to Randy's Ring & Pinion and had them replace the clutch pack. It is tight now and even chirps the inside tire on corners, if you get on it.

03-21-2008, 07:20 AM	#6
slammed1 1972 Chevrolet SWB Join Date: Jan 2008 Location: FT Smith AR Posts: 512	Re: Posi rear axle question It does sound as if your posi is toasted. Parts readily available and unless your confident in your tools and work,I would have another person build it if needed.I had one in a 67 Impala get week and I could jack it up and rotate one rear wheel with my hand and the other wheel would spin completely opposite,just like an open but I knew 110% it was posi. The rear was rebuilt and is doing time in our Drag/Street Race 68 Impala now. __________________ My New thread with pics (not my build thread yet.) http://67-72chevytrucks.com/vboard/s...46#post2573646 1972 Chevrolet 1/2 ton short wide bed,68 frt clip Project. 1980 Camaro Inherited when father passed,68K Miles 2003 Ford Mach1 FUN as Hell!! 2002 Dodge Ram 5-8 slam Rolling BillBoard (Gone not forgot) 2004 Dodge Ram HEMI 10" lifted on 37's and 2wd.

03-21-2008, 07:53 AM	#7
PICKMUP "Trucks with Class" Join Date: Jul 2000 Location: OLYMPIA, WA, USA Posts: 8,158	Re: Posi rear axle question Here is one I pulled today. It spun like an open. There was no indication it was posi except listing on the SPID. Attached Images

03-21-2008, 08:29 AM	#8
67 cst swb Senior Member Join Date: Nov 2001 Location: Rapid City, SD Posts: 2,281	Re: Posi rear axle question So, what does it cost to have a posi clutch pack replaced at Randy's? __________________ My Trucks: 1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project 1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver 1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck 1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck 2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White

03-21-2008, 11:28 AM	#9
Mint68 Registered User Join Date: Nov 2004 Location: Nebraska Posts: 762	Re: Posi rear axle question I thought mine acted wierd when on jack stands, but on the ground it will leave two marks, and likes to slide either way in the snow. I was going to have mine rebuilt, but I was told it was a non rebuildable unit. Seems mine has cones not cluthes.

03-21-2008, 01:41 PM	#10
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Posi rear axle question In the HO52,if that`s what you actually have,only the NoSpin/Detroit Locker came from factory.No clutches,not a posi.If it has a Dana60 it could have the PowerLock posi. I had a problem with a NoSpin where only one wheel spun full-time,like a live axle.It was worse than an open rear because I got nothing from one side and full power all the time to the other.Believe me,if you`ve ever had this you`d realize how nice a bias open rear operates.With one wheel under power at all times you can`t back up a stone incline.It`s like a go cart.The only think I could figure was a weak side spring.But,I couldn`t see anything wrong.I just put another unit in that I had. __________________ "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 ~



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