Best choice to have new 3 series carrier/3:23/Posi unit put in or none of them?
October 16th, 2016, 04:13 PM
#1
Registered User
Thread Starter
Join Date: Nov 2013
Location: St. Louis
Posts: 2,357
Best choice to have new 3 series carrier/3:23/Posi unit put in or none of them?
41-15 gmc left thread on bolts. Open
SA B140. Has brake line mount drilled and tapped to top. Cover was 8.2 type with scalloped sides.
This is the TYPE differential that was in my "last" cutlass with (as I was told by previous owner) 3:23 Earon Posi.
# 1234771 pinion gear.
No pictures of the next ones.
Second is a SA O 240. Drilled and tapped brake hose mount on top. Did not open yet. 2:73 open
Third is a R2 Oxxx. Drilled and tapped on top also for brake hose mount. 41-16 2:56 open
Last edited by Gary M; October 16th, 2016 at 04:19 PM.
October 18th, 2016, 08:57 AM
#3
Registered User
Join Date: Feb 2013
Location: Phoenix, AZ
Posts: 13,756
I think those are all 8.5" 10 bolt corporate rears, so you are correct they are all the same (other than gear ratios which you are changing anyway) and it doesn't make any difference which one you use.
October 18th, 2016, 09:06 AM
#4
Registered User
Join Date: Nov 2008
Location: Redmond, Oregon
Posts: 3,326
41-15 on ring gear If I am not mistaken means 41 teeth on ring gear and 15 on pinion which means 2:73 ratio. Moving to 3:23 would be a great improvement for low end performance. you will lose a little top end highway cruising but it should still be very nice. All is assuming you are running an automatic with 1-1 final drive.
Brand of posi not really that much of an issue. Just adding it will be a big improvement for out of the hole performance.
Just my input I am very fond of 3:23 gears
Larry
Brand of posi not really that much of an issue. Just adding it will be a big improvement for out of the hole performance.
Just my input I am very fond of 3:23 gears
Larry
October 18th, 2016, 06:21 PM
#6
Registered User
Join Date: May 2011
Location: Delta BC Canada
Posts: 3,688
Thoughtd
Wether you run the 2.73 or the 3.23 will depend on your rear tire height choice and on how you plan to use the car.
You could also split the difference and go for 3.08 gears. I have 8.5" 3.08 crown and pinion if you wish to trade for your 3.23 gear set.
You could also split the difference and go for 3.08 gears. I have 8.5" 3.08 crown and pinion if you wish to trade for your 3.23 gear set.
Last edited by oldsmobiledave; October 18th, 2016 at 06:25 PM.
October 19th, 2016, 07:48 PM
#7
Registered User
Thread Starter
Join Date: Nov 2013
Location: St. Louis
Posts: 2,357
looks like maybe 7.5 Thoughts?
SA B XXX on markings 41-15 gears
LM501314 on bearing race inside pumpkin
correct measure? does not look more than 7+-
495 on casing Diff has drilled and tapped brake line connector on top, 1 1/4 pinion nut,straps instead of u bolts on u joints, bolt in axles, very bottom bolt on the cover measured to the next bolt on either side measures 3 1/4 +-. 28 spline axles. Crankshaftcoalition.com has more tips on I.D. which one you have.
Last edited by Gary M; October 19th, 2016 at 08:27 PM.
Thread
Thread Starter
Forum
Replies
Last Post
68Tom
Parts For Sale
1
April 24th, 2012 12:39 PM
Redog
Parts For Sale
1
February 9th, 2009 01:13 PM
