putting in a posi unit - The 1947 - Present Chevrolet & GMC Truck Message Board Network

outacontrl86 · 08-17-2006, 06:31 PM

so i got a posi unit for a 8.5 rear end... i want to mabye put it in my truck it is a 86 k10 so it has 10 bolts on the cover is it a 8.5 rear?? if so do i take the cover off make sure i keep the shims in the right place swap the carirer bolt on the gears and put it back in?? if it is easy i think im gunna do it

mhicks · 08-18-2006, 01:18 PM

I've heard that everything has to almost be perfect or it will wear out in no time. Also requires special tools.

piecesparts · 08-18-2006, 01:20 PM

I am thinking that if you don't take the time and trouble to set the backlash and engagement, then a troublesome time is a comin.

lou6t4gto · 08-18-2006, 01:54 PM

IF all you're changing is the "posi" unit,(same ring & pinion), as long as you get the backlash,(distance between the teeth on the ring gear & the pinion teeth), as long as they are the same, you'll be fine. Just don't count on that the shims that come out will put the ring gear in the same setting as the unit you took out. because of the different center(posi) & the different bearings, it will move sideways one way or another a few thousanths.

08-17-2006, 06:31 PM	#1
outacontrl86 Registered User Join Date: Mar 2006 Location: long island Posts: 25	putting in a posi unit so i got a posi unit for a 8.5 rear end... i want to mabye put it in my truck it is a 86 k10 so it has 10 bolts on the cover is it a 8.5 rear?? if so do i take the cover off make sure i keep the shims in the right place swap the carirer bolt on the gears and put it back in?? if it is easy i think im gunna do it

08-18-2006, 01:18 PM	#2
mhicks Registered User Join Date: Jan 2004 Location: Weatherford,Tx Posts: 747	Re: putting in a posi unit I've heard that everything has to almost be perfect or it will wear out in no time. Also requires special tools.

08-18-2006, 01:20 PM	#3
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: putting in a posi unit I am thinking that if you don't take the time and trouble to set the backlash and engagement, then a troublesome time is a comin.

08-18-2006, 01:54 PM	#4
lou6t4gto Registered User Join Date: Aug 2006 Location: ocala fl Posts: 19	Re: putting in a posi unit IF all you're changing is the "posi" unit,(same ring & pinion), as long as you get the backlash,(distance between the teeth on the ring gear & the pinion teeth), as long as they are the same, you'll be fine. Just don't count on that the shims that come out will put the ring gear in the same setting as the unit you took out. because of the different center(posi) & the different bearings, it will move sideways one way or another a few thousanths.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.