Posi Mod

Drivetrain discussion including Transmission, Differential, Driveshaft, and related items.
Post Reply
jackleg
Posts: 99
Joined: Thu May 05, 2016 2:25 am
Location: SW MI

Posi Mod

Post by jackleg » Mon Dec 19, 2016 4:30 pm

I have a 3.45 rear diff from a 2011 Camaro. It has been brought to my attention that there are kits to modify the clutches in the differential and am curious if anyone else has experience or input about this subject. The 2.92 in the Caprice now (140K mikes) will at times experience the "one tire fire".
There are two kits that I looked at-

1) Jannetty posi mod that adds a coupe of extra OEM clutches to the pack already installed in the diff (reuses some of the clutches) and a Ford preload spring (EOAZ-4214-A). Some of the write ups on this say that its a bit aggressive- tires dragging around corners etc. http://www.jreperformanceparts.com/prod ... -posi-mod/" onclick="window.open(this.href);return false;

2) Camaro Central CLU-595 kit. Replaces ALL the OEM clutches with a different design, adds a preload spring, and has selective spacers to adjust the clutch preload. http://www.camarocentral.com/2010_2015_ ... lu-595.htm" onclick="window.open(this.href);return false;

I ordered the Camaro Central kit for the 3.45 that's going in the Caprice - is "on sale" + they have a 10% off discount code right now. however its on backorder (no biggie- theres over a foot of snow here right now). I'll post up some pics when I get to the install

Some things I'm also curious about- a cheap way out might be some sort of home brew Jannetty mod- buy the Ford EOAZ-4214-A spring and take a couple of clutches out of the Caprice diff and add them to Camaro diff, Don't know if the clutches are the same size with out disassembly.
Also wondering if someone got ahold of one of the 3:27 Camaro diffs- some have LSD and some don't. The ones that don't already have LSD maybe if they have the same case and side gears the Camaro Central kit could be added to make it into LSD?
2011 9C1 6.0
RCR "Little Lunati" 219/223 .625/.625 112+0
Kooks headers, hi flow cats, Dynomax Super Turbos
Flex fuel tune

kevink
Posts: 332
Joined: Sun Aug 09, 2015 5:55 pm

Re: Posi Mod

Post by kevink » Mon Dec 19, 2016 6:51 pm

Too bad it's on back order as I was just about to order mine. Did they say when it might ship?

Navy Lifer
Administration Staff
Posts: 1487
Joined: Tue Mar 19, 2013 11:30 pm
Location: Canton GA

Re: Posi Mod

Post by Navy Lifer » Mon Dec 19, 2016 9:29 pm

There are other options when using the Camaro differential:

Auburn 5420138
http://aftermarket.auburngear.com/new-p ... -bolt.html" onclick="window.open(this.href);return false;
3.27:1, 3.45:1, & 3.73:1

Eaton - Detroit Truetrac 912A686
http://www.eaton.eu/Eaton/ProductsServi ... /index.htm" onclick="window.open(this.href);return false;
2010 - 2015 Camaro 218mm 32 3.45, 3.73

(Truetrac operates by same principle as TORSEN differential--standard on Z/28)
https://torsen.com/" onclick="window.open(this.href);return false;
https://torsen.com/how-it-works/" onclick="window.open(this.href);return false;

Camaro differentials:
Z/28 3.91
http://www.gmpartsdirect.com/chevrolet/ ... rntal-assy" onclick="window.open(this.href);return false;

SS 3.27 manual
http://www.gmpartsdirect.com/chevrolet/ ... rntal-assy" onclick="window.open(this.href);return false;

SS 3.27 auto
http://www.gmpartsdirect.com/chevrolet/ ... rntal-assy" onclick="window.open(this.href);return false;

SS 3.45 manual
http://www.gmpartsdirect.com/chevrolet/ ... rntal-assy" onclick="window.open(this.href);return false;

SS-1LE 3.91 manual
http://www.gmpartsdirect.com/chevrolet/ ... rntal-assy" onclick="window.open(this.href);return false;

jackleg
Posts: 99
Joined: Thu May 05, 2016 2:25 am
Location: SW MI

Re: Posi Mod

Post by jackleg » Mon Dec 19, 2016 10:41 pm

kevink wrote:Too bad it's on back order as I was just about to order mine. Did they say when it might ship?
Was told "Probably after the 1st of Jan" so not real specific-
2011 9C1 6.0
RCR "Little Lunati" 219/223 .625/.625 112+0
Kooks headers, hi flow cats, Dynomax Super Turbos
Flex fuel tune

jackleg
Posts: 99
Joined: Thu May 05, 2016 2:25 am
Location: SW MI

Re: Posi Mod

Post by jackleg » Sat Dec 24, 2016 12:57 pm

The Camaro Central kit arrived-
Has 6 side gear steels, 8 case steels, an assortment of clutch pre load shims .035 to .010, and a pre load "S" spring.
They have a waffle pattern texture on both sides of the steel- no fiber. It will be a while before I can get to the install.. I'll post how it all fits together once it's done
Attachments
KIMG0127.JPG
KIMG0127.JPG (135.2 KiB) Viewed 6866 times
KIMG0128.JPG
KIMG0128.JPG (139.81 KiB) Viewed 6866 times
2011 9C1 6.0
RCR "Little Lunati" 219/223 .625/.625 112+0
Kooks headers, hi flow cats, Dynomax Super Turbos
Flex fuel tune

jackleg
Posts: 99
Joined: Thu May 05, 2016 2:25 am
Location: SW MI

Re: Posi Mod

Post by jackleg » Sun Jan 15, 2017 7:42 pm

I got the thing apart. 1st had to make up one of these housing spreaders. Once the diff case is out of the housing, the case has to be taken apart to get at the clutches. The case half bolts are E18 that have a shallow head. My E18 socket had an internal taper where the splines diddn't fully start until about 1/8" into the socket. I had to file the socket down to where the splines started immediately to properly fit the bolts. The other problem I had was one of the ring gear bolts was not tight- found it to be broken off a few threads in. I managed to get the piece out of the gear but now have to get a new bolt set. I'm glad I found it now, but am a little irritated that my "11K mile take out" would have had issues had I just swapped the entire unit out. (maybe it was 11k miles a quarter mile at a time??)
The OEM Camaro had 4 clutches per side, The CLU-595 kit has 7 clutches per side. Once I get it all swapped out, I plan to disassemble the Caprice diff to see what its made of
Attachments
KIMG0174.jpg
KIMG0174.jpg (150.45 KiB) Viewed 6784 times
KIMG0176.JPG
KIMG0176.JPG (90.04 KiB) Viewed 6784 times
2011 9C1 6.0
RCR "Little Lunati" 219/223 .625/.625 112+0
Kooks headers, hi flow cats, Dynomax Super Turbos
Flex fuel tune

jackleg
Posts: 99
Joined: Thu May 05, 2016 2:25 am
Location: SW MI

Re: Posi Mod

Post by jackleg » Sun Apr 09, 2017 3:03 am

I removed the Caprice Diff and pulled it apart to have a look. It's appears that there are no interchangeable parts with the Camaro diff. The Camaro differential case is looks stronger, but I think the Caprice housing design is better- the housing comes apart into two halves that clamp the differential between the 2 where the Camaro has the 2 bearing caps. The Caprice diff side bearings are larger.
Attachments
cap dif 11.jpg
Camaro / Caprice
cap dif 11.jpg (67.1 KiB) Viewed 6546 times
cap dif 12.jpg
Camaro / Caprice
cap dif 12.jpg (89.42 KiB) Viewed 6546 times
cap diff 13.jpg
Caprice Housing split
cap diff 13.jpg (120.1 KiB) Viewed 6546 times
2011 9C1 6.0
RCR "Little Lunati" 219/223 .625/.625 112+0
Kooks headers, hi flow cats, Dynomax Super Turbos
Flex fuel tune

kevink
Posts: 332
Joined: Sun Aug 09, 2015 5:55 pm

Re: Posi Mod

Post by kevink » Mon Nov 13, 2017 4:32 pm

I also installed this clutch kit in my Camaro rear. I have a few hundred hard miles on it (lots of burnouts and hard acceleration) and it's working perfectly. The only issue with the install was that you can't follow their instructions for setting preload. The instructions are simply wrong. If you set it for maximum preload, the case halves won't bolt together and the side and spider gears will bind. What you need to do is shim it as tight as possible while still having some clearance between the side gears and spider gears.

Post Reply