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Ford 9" Rear Identity

EarlyElway

Jr. Member
Joined
Dec 11, 2012
Messages
58
Loc.
Shawnee, KS
Hey Guys,

I am trying to figure out weather I have the Ford Trac Lock differential or an open carrier on the rear end with out taking it apart.

From what I have been reading there should be a tag on one of the 10 bolts but mine does not appear to be there. I did find a stamp on the carrier case near the top on he passenger side.

It appears to read 4L27, there may be another character in front of the 4 but I cannot be sure.

Is there any way to tell from the VIN in the glove box?

If I determine that it is the Ford Factory trac lock how difficult is it to rebuild it so the clutches run a little tighter for better performance?

I can't affored the detroit tru-track that everyone seems to recommend at this time.
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
The axle code on the VIN tag will tell you what it came with. No guarranty that's still in there though.
 

ENDLIFE

Sr. Member
Joined
Nov 17, 2011
Messages
453
Unless someone put one in, you should have an open differential. The easiest way to check is to put your rear end up on jack stands, turn one wheel, and see if they both spin in the same direction. If one wheel spins in the opposite direction you have an open differential, and if they spin in the same direction you have a limited slip or a locker.
 

ENDLIFE

Sr. Member
Joined
Nov 17, 2011
Messages
453
I thought that was just an option, and if it wasn't requested you got an open diff?
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
I thought that was just an option, and if it wasn't requested you got an open diff?

It was an option. It was also included in some other option packages like the heavy duty packages. Dealers would have ordered a variety of options on the Broncos they bought to appeal to a greater range of their potential customers. Therefore, you could have found something on a lot that you liked. You didn't have to special order one to get a limited slip dif.
 

KyleQ

Bronco Guru
Joined
Apr 24, 2008
Messages
5,480
Unless someone put one in, you should have an open differential. The easiest way to check is to put your rear end up on jack stands, turn one wheel, and see if they both spin in the same direction. If one wheel spins in the opposite direction you have an open differential, and if they spin in the same direction you have a limited slip or a locker.

This isn't always true either - sure, a spool or welded carrier will always spin both together, but my trac-loc, torsen T-2 and power-lok will act like an open differential without any load on them.

The only way to be sure is to pull the 3rd out and look- sorry.
 
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EarlyElway

Jr. Member
Joined
Dec 11, 2012
Messages
58
Loc.
Shawnee, KS
This isn't always true either - sure, a spool or welded carrier will always spin both together, but my trac-loc, torsen T-2 and power-lok will act like an open differential without any load on them.

The only way to be sure is to pull the 3rd out and look- sorry.

Okay...well I have the carrier out now and need some help identifying what I have. What are the internal trademarks of a trac-loc that I can look for?
 

bronconut73

Bronco Guru
Joined
Aug 7, 2012
Messages
9,916
I believe the ring gear bolts on the track lok are of a shouldered variety where as tbe open dif's are not. Read that in JBG catalog a few years back. They also sell rebuild kits too.
 

Quick & Dirty

Sr. Member
Joined
Feb 15, 2004
Messages
826
The ring gear bolts are recessed. LS on the right.

LS.JPG




but my trac-loc, torsen T-2 and power-lok will act like an open differential without any load on them.

The Torsen is a torque biasing diff, so it will act open when unloaded, but the trac-loc and power-lok have pre-loaded clutch packs that should require a minimum of torque to break loose. The Ford spec is 50-200 ft lbs to break loose, to keep turning is less. 50 ft-lbs isn't much help at the tire, and once the clutches start slipping, it is essentially open. The power-lok has a cross shaft that increases the clutch pre-load with increased torque. The trac-loc does not.
 
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KyleQ

Bronco Guru
Joined
Apr 24, 2008
Messages
5,480
The Torsen is a torque biasing diff, so it will act open when unloaded, but the trac-loc and power-lok have pre-loaded clutch packs that should require a minimum of torque to break loose. The Ford spec is 50-200 ft lbs to break loose, to keep turning is less. 50 ft-lbs isn't much help at the tire, and once the clutches start slipping, it is essentially open. The power-lok has a cross shaft that increases the clutch pre-load with increased torque. The trac-loc does not.

Yup - I've had a trac-loc for over 10 years and have rebuilt it a few times. Mine will spin like an open diff in the air but on dirt, tar, snow and all it locks up without an issue - maybe its just me.

The power-lok is the strongest limited slip on the market - I've got one in the front my my pickup and its brutal on pavement in parking lots, blew up lots of D44 shafts until I went to Spicer joints and full circle snap rings.
 
OP
OP
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EarlyElway

Jr. Member
Joined
Dec 11, 2012
Messages
58
Loc.
Shawnee, KS
The ring gear bolts are recessed. LS on the right.

LS.JPG






The Torsen is a torque biasing diff, so it will act open when unloaded, but the trac-loc and power-lok have pre-loaded clutch packs that should require a minimum of torque to break loose. The Ford spec is 50-200 ft lbs to break loose, to keep turning is less. 50 ft-lbs isn't much help at the tire, and once the clutches start slipping, it is essentially open. The power-lok has a cross shaft that increases the clutch pre-load with increased torque. The trac-loc does not.

Awesome! Thanks for the photos. That really helped and I do have a trac loc in there according to that photo.

Now the question is how easy is it to rebuild it to have a stronger better performing track lock?
 

KyleQ

Bronco Guru
Joined
Apr 24, 2008
Messages
5,480
Awesome! Thanks for the photos. That really helped and I do have a trac loc in there according to that photo.

Now the question is how easy is it to rebuild it to have a stronger better performing track lock?

You are in luck - Mustang's have had these forever, so there are tons of guides and kits out these for these.

Take a peek here for starters - http://www.moddedmustangs.com/forums/5-0-mustangs/58740-trac-lok-rebuild-how.html

Here are some pics of my 8.8 rebuild - it looks different, but the principals for the clutching are the same. A common thing for people to do is add more clutches to make the spring tighter.

Mine was trashed-
 
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EarlyElway

Jr. Member
Joined
Dec 11, 2012
Messages
58
Loc.
Shawnee, KS
Thanks again for the good info.

I am attaching a photo of the ring and pinion and there seams to be a groove at the end of the pinion and I am not sure if it is supposed to be there. The bearing is shot and I am wondering if a new bearing will seat on the pinion with the grooves?

I really dont want to have to buy new gears.

Thoughts?
 

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Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
It's not supposed to be there. You have a nice paperweight.
 

Justafordguy

Contributor
Bronco Guru
Joined
Sep 26, 2009
Messages
6,253
X2, you need to replace the gears. Also be sure to replace the pinion support bearing because that's probably what took that pinion out. Make sure the support isn't cracked also.
 

KyleQ

Bronco Guru
Joined
Apr 24, 2008
Messages
5,480
Yeah, sorry. Put up a wanted add and I bet you someone will have a set of gears for you.
 
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