rear end code - The 1947 - Present Chevrolet & GMC Truck Message Board Network

pat · 03-28-2004, 11:34 PM

Im trying to figure out what the ratio is on a posi rear end off of a 71 pickup. I could only find the following on the axle and cant match them up with anything.

CON3
B81
GM60

Anybody know what it is?
Thanks

402GLH · 03-28-2004, 11:56 PM

No idea on the decode, worst comes to worst you can count the teeth..
http://www.usgear.com/tl/gm2.htm

TIMSPEED · 03-29-2004, 06:11 AM

Are you sure you're looking in the right place? It will require a GOOD cleaning, and the numbers will be stamped exactly 6" out from the pumpkin, at about 2'o'clock, on the passenger side axle tube. It should be something like Txx.

pat · 03-29-2004, 02:43 PM

Quote:

Originally posted by TIMSPEED
Are you sure you're looking in the right place? It will require a GOOD cleaning, and the numbers will be stamped exactly 6" out from the pumpkin, at about 2'o'clock, on the passenger side axle tube. It should be something like Txx.

All of this i found on the pumpkin. I will check for more numbers there when I get a chance.
thanks

pat · 03-31-2004, 12:31 AM

I found this:
NF 3896838

It was on the passenger side of the pumpkin. It was dark and I didnt see a number on the axle, does this # help any?

pat · 04-01-2004, 01:38 PM

Do I need to look for another new number?
Does this one not mean anything?

TIMSPEED · 04-01-2004, 09:02 PM

Quote:

Originally posted by pat
Do I need to look for another new number?
Does this one not mean anything?

Yes, trust me, it's hard to find, but they're there. Just get a wet brillo pad, and a couple clean dry paper towels. Start scrubbing the axle tube, at about the 2'o'clock' spot, 6" out from the pumpkin. Trust me, the numbers aren't molded, they're STAMPED with a small die.

TIMSPEED · 04-01-2004, 09:10 PM

Here, this picture should help...Notice the CLEAN area? THAT'S how clean you have to get it to see the numbers...SHINY clean.

pat · 04-02-2004, 03:38 PM

Thanks a lot TIMSPEED, Ill check on that today. Im just hoping this posi hasnt got really low gears.

pat · 04-03-2004, 02:39 PM

Got it this time:
THBW0416E

TIMSPEED · 04-03-2004, 05:39 PM

Quote:

Originally posted by pat
THBW0416E

THB = 3.07 gears

pat · 04-04-2004, 01:56 PM

Nice, 3.07 posi is going into my truck.
Thanks TIMSPEED

Razor454 · 04-08-2004, 04:14 AM

In these old rear ends you never know if someone changed the ratio at any point in time. The best way to find the ratio is to take off the diff. cover and take a look at the ring gear. On the outside part of the ring gear there will be two numbers. Take these two numbers and divide them, this will tell you what ratio you have. For example you might see the numbers 41 12 which comes out to be a 3.42 ratio

03-28-2004, 11:34 PM	#1
pat Senior Member Join Date: Jul 2002 Location: Lindsay, TX Posts: 1,245	rear end code Im trying to figure out what the ratio is on a posi rear end off of a 71 pickup. I could only find the following on the axle and cant match them up with anything. CON3 B81 GM60 Anybody know what it is? Thanks __________________ 68 Chevy 383/350 w/shift kit, 380hp/425ft-lbs, 4.5/5 drop, 17" TT2s 64 Cadillac Sedan DeVille

03-28-2004, 11:56 PM	#2
402GLH Registered User Join Date: Mar 2004 Posts: 37	;( No idea on the decode, worst comes to worst you can count the teeth.. http://www.usgear.com/tl/gm2.htm __________________ 1972 Cheyenne Olive over Dark Green, Longbed 402BBC, TH400

03-29-2004, 06:11 AM	#3
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Are you sure you're looking in the right place? It will require a GOOD cleaning, and the numbers will be stamped exactly 6" out from the pumpkin, at about 2'o'clock, on the passenger side axle tube. It should be something like Txx. __________________ I have a few cars... See Them Here

03-31-2004, 12:31 AM	#5
pat Senior Member Join Date: Jul 2002 Location: Lindsay, TX Posts: 1,245	I found this: NF 3896838 It was on the passenger side of the pumpkin. It was dark and I didnt see a number on the axle, does this # help any? __________________ 68 Chevy 383/350 w/shift kit, 380hp/425ft-lbs, 4.5/5 drop, 17" TT2s 64 Cadillac Sedan DeVille

04-01-2004, 01:38 PM	#6
pat Senior Member Join Date: Jul 2002 Location: Lindsay, TX Posts: 1,245	Do I need to look for another new number? Does this one not mean anything? __________________ 68 Chevy 383/350 w/shift kit, 380hp/425ft-lbs, 4.5/5 drop, 17" TT2s 64 Cadillac Sedan DeVille

04-01-2004, 09:10 PM	#8
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Here, this picture should help...Notice the CLEAN area? THAT'S how clean you have to get it to see the numbers...SHINY clean. Attached Images __________________ I have a few cars... See Them Here

04-02-2004, 03:38 PM	#9
pat Senior Member Join Date: Jul 2002 Location: Lindsay, TX Posts: 1,245	Thanks a lot TIMSPEED, Ill check on that today. Im just hoping this posi hasnt got really low gears. __________________ 68 Chevy 383/350 w/shift kit, 380hp/425ft-lbs, 4.5/5 drop, 17" TT2s 64 Cadillac Sedan DeVille

04-03-2004, 02:39 PM	#10
pat Senior Member Join Date: Jul 2002 Location: Lindsay, TX Posts: 1,245	Got it this time: THBW0416E __________________ 68 Chevy 383/350 w/shift kit, 380hp/425ft-lbs, 4.5/5 drop, 17" TT2s 64 Cadillac Sedan DeVille

04-04-2004, 01:56 PM	#12
pat Senior Member Join Date: Jul 2002 Location: Lindsay, TX Posts: 1,245	Nice, 3.07 posi is going into my truck. Thanks TIMSPEED __________________ 68 Chevy 383/350 w/shift kit, 380hp/425ft-lbs, 4.5/5 drop, 17" TT2s 64 Cadillac Sedan DeVille

04-08-2004, 04:14 AM	#13
Razor454 Registered User Join Date: Feb 2004 Location: Stokesdale, North Carolina Posts: 341	In these old rear ends you never know if someone changed the ratio at any point in time. The best way to find the ratio is to take off the diff. cover and take a look at the ring gear. On the outside part of the ring gear there will be two numbers. Take these two numbers and divide them, this will tell you what ratio you have. For example you might see the numbers 41 12 which comes out to be a 3.42 ratio __________________ 1967 SwB, 454 BB, 4L80E trans, 3.73 eaton posi 1997 C2500 Ext Cab 5.7 Liter 1955 3/4 ton 1st series w/ 235 straight six Sold it



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