The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1960 - 1966 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 05-10-2011, 06:11 PM   #1
'70GMCStep
Registered User
 
Join Date: Jul 2007
Location: Rogersville, Missouri
Posts: 89
Positrac rear end

Have a little concern.

I think my positrac clutches on my rear end are going bad on my '65. It grinds when going around corners especially if I accelerate even a bit, and now it is getting worse. Will or did this do any harm to my 700 r-4 and the drive line while I was driving it for...quite a while until noticing it getting bad today?

Thanks guys.

'70GMCStep

1970 GMC Stepside
1965 Chevy LWB
'70GMCStep is offline   Reply With Quote
Old 05-10-2011, 09:12 PM   #2
Alan's Classic
1 thing at a time is progress.
 
Alan's Classic's Avatar
 
Join Date: Jun 2007
Location: Ball Ground GA
Posts: 5,511
Re: Positrac rear end

When was the last time you changed the fluid and did you put any posi additive in it?
Alan's Classic is offline   Reply With Quote
Old 05-10-2011, 11:06 PM   #3
'70GMCStep
Registered User
 
Join Date: Jul 2007
Location: Rogersville, Missouri
Posts: 89
Re: Positrac rear end

About two years ago and it was added to the rear end.


'70GMCStep

'70 GMC Stepside
'65 Chevy C-10
'70GMCStep is offline   Reply With Quote
Old 05-11-2011, 01:32 AM   #4
Captainfab
60-66 Nut

 
Join Date: Mar 2007
Location: Coeur d'Alene, Idaho
Posts: 23,252
Re: Positrac rear end

If indeed your clutches are going out in your posi, that isn't going to hurt your trans or driveshaft any. Have you checked your U-joints?
__________________
Power Steering Box Adapter Plates For Sale HERE
Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE
Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE
Hydroboost Mounting Plates HERE
Captainfab is offline   Reply With Quote
Old 05-11-2011, 06:01 PM   #5
wildearp
Registered User
 
wildearp's Avatar
 
Join Date: Jul 2010
Location: Tucson Arizona
Posts: 165
Re: Positrac rear end

Time to get a true-trac.
wildearp is offline   Reply With Quote
Old 05-11-2011, 06:26 PM   #6
awbrown
Registered User
 
Join Date: Aug 2009
Location: Detroit MI
Posts: 1,209
Re: Positrac rear end

I think all posi's make noise at some time or another , it seems to me that the posi lubes are not all the same , friction modifiers differ from factory lubes to aftermarket lubes ... go to the dealer and get the GM stuff and if one doenst do it get another ......as long as it burns both tires dont care if it makes noise...mine makes noise and I just ignore it ....
awbrown is offline   Reply With Quote
Old 05-11-2011, 06:35 PM   #7
lakeroadster
Account Suspended
 
Join Date: Sep 2009
Location: High Plains of Colorado
Posts: 2,485
Re: Positrac rear end

It definately puts some high loading into the rear suspension components and can overstress bushings, I learned this the hard way on my coil over shock suspended Model A that runs a 12 bolt posi.

Before I put the posi-additive in it the rear axle the non-slipping posi ate the bushings out of the shocks where they attached to the rear axle.

I put enough additive in it such that it didn't chatter going around corners, installed some new bushings in the shocks and haven't had any problems since.

Might be worth looking at your track bar bushings and the trailing arm bushings. Better safe than sorry.

Happy trails!

John

PS: yes it does still leave two nice burnout tracks, so the posi clutches are grabbing during hard launches.

Last edited by lakeroadster; 05-11-2011 at 06:39 PM.
lakeroadster is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:02 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com