How to tell if rear is limited slip? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ScottH** · 12-13-2003, 12:33 AM

Ok, obviously a posi rear is easy, same goes for open. But how can u tell by looking (jacking up, etc.) at a rear if it is a limited slip diff?

Any info is appreciated. Thanks.

lukecp · 12-13-2003, 12:39 AM

When both wheels are in the air, turn one by hand. If the opposite wheel turns in a different direction, it is open. If it turns in the same direction, you have a limited slip.

Of you could just go do a burnout and see if you leave too marks

breeh · 12-13-2003, 12:43 AM

Ratios are most likely 4:10 or 4:56. 4:10 was standard and the 4:56 was optional. Also, the big block trucks often came with 3:54's but they aren't as common.

dinnut · 12-13-2003, 01:13 AM

Quote:

Originally posted by yellow72custom
When both wheels are in the air, turn one by hand. If the opposite wheel turns in a different direction, it is open. If it turns in the same direction, you have a limited slip.

Of you could just go do a burnout and see if you leave too marks

if he leaves two marks he wouldnt have a limited slip i dont think. limited slip means if one side loses traction the other spins. dont know how one of these would act if you tried to do a burnout. what do posi's do if you turn the wheels up in the air?

lukecp · 12-13-2003, 01:15 AM

Quote:

Originally posted by dinnut

if he leaves two marks he wouldnt have a limited slip i dont think. limited slip means if one side loses traction the other spins. dont know how one of these would act if you tried to do a burnout. what do posi's do if you turn the wheels up in the air?

Dinnut, limited slip and posi are the same thing. Just different names.

If the axle is in working order, it will leave 2 marks, but one may be a little lighter than the other.

dinnut · 12-13-2003, 01:20 AM

i thought limited slip was where if one wheel loses traction the other gains the power and in a posi both wheels had power full time. thanks for clearing that up

70cst10_05 · 12-13-2003, 02:28 AM

i have a posi in the truck i drive, it started makin noise a few days ago, it'll sometimes leave dual black marks other times it'll start to do it, then go to a 1 legger, but its all fun

jimfulco · 12-13-2003, 05:21 AM

I've seen a couple of peg-leggers that would spin 2 at a time.

A.P. · 12-13-2003, 06:53 AM

Huck · 12-13-2003, 10:29 AM

It all kind of depends. I've seen open rears drive two wheels with the right gearing, tires, surface. The only setup that drives both weels constantly is a locked rear which is really only safe off road as it skids around turns as one wheel turns faster then the other. The terms posi and limited slip refers to the rear where one wheel drives till enough torque is applied then it drives the second wheel. Typically the pass side, right rear gets more twist then the drivers side due to torque of the engine etc.
Newer vehicles have "limited slip" especially with front wheel drive where the "slipping wheel" has the brake applied automatically thereby reducing loss of traction.

1969 GMC · 12-13-2003, 05:31 PM

positraction was GM's way of saying "limited slip"

detroit lockers will unlock if you coast around corners, so they are somewhat streetable. somewhat, because they will still pop and clunk.

72c10step · 12-14-2003, 07:50 PM

I have Posi!!!

<<<(See avatar)

dinnut · 12-14-2003, 07:52 PM

i see now that posi and limited slip are the same thing

12-13-2003, 12:33 AM	#1
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,191	How to tell if rear is limited slip? Ok, obviously a posi rear is easy, same goes for open. But how can u tell by looking (jacking up, etc.) at a rear if it is a limited slip diff? Any info is appreciated. Thanks.

12-13-2003, 12:39 AM	#2
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	When both wheels are in the air, turn one by hand. If the opposite wheel turns in a different direction, it is open. If it turns in the same direction, you have a limited slip. Of you could just go do a burnout and see if you leave too marks __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

12-13-2003, 12:43 AM	#3
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	Ratios are most likely 4:10 or 4:56. 4:10 was standard and the 4:56 was optional. Also, the big block trucks often came with 3:54's but they aren't as common. __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

12-13-2003, 01:20 AM	#6
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	i thought limited slip was where if one wheel loses traction the other gains the power and in a posi both wheels had power full time. thanks for clearing that up __________________ 70 longbed 496/th400/Ford 9"

12-13-2003, 02:28 AM	#7
70cst10_05 Registered User Join Date: Dec 2002 Location: Summerfield, Ks Posts: 745	i have a posi in the truck i drive, it started makin noise a few days ago, it'll sometimes leave dual black marks other times it'll start to do it, then go to a 1 legger, but its all fun __________________ 1970 Chevy CST/10 1970 Chevy CST/10 1972 Chevy C/10 1972 Chevy Suburban K/10 2019 Silverado 2500 Duramax Kevin

12-13-2003, 05:21 AM	#8
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	I've seen a couple of peg-leggers that would spin 2 at a time.

12-13-2003, 06:53 AM	#9
A.P. Black 72 Chevy Join Date: May 2002 Location: Los Angeles, California Posts: 662

12-13-2003, 10:29 AM	#10
Huck Senior Member Join Date: Jun 2001 Location: Shelbyville, KY Posts: 3,261	It all kind of depends. I've seen open rears drive two wheels with the right gearing, tires, surface. The only setup that drives both weels constantly is a locked rear which is really only safe off road as it skids around turns as one wheel turns faster then the other. The terms posi and limited slip refers to the rear where one wheel drives till enough torque is applied then it drives the second wheel. Typically the pass side, right rear gets more twist then the drivers side due to torque of the engine etc. Newer vehicles have "limited slip" especially with front wheel drive where the "slipping wheel" has the brake applied automatically thereby reducing loss of traction.

12-13-2003, 05:31 PM	#11
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	positraction was GM's way of saying "limited slip" detroit lockers will unlock if you coast around corners, so they are somewhat streetable. somewhat, because they will still pop and clunk. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

12-14-2003, 07:50 PM	#12
72c10step WHYBYNU when old will do? Join Date: Jul 2003 Location: Loudon, NH Posts: 876	I have Posi!!! <<<(See avatar) __________________ -72 Chevy C10 Stepside -2002 Chevy Silverado 2500HD 4x4 -1984 Jeep CJ7 -1995 Polaris XCR600 Custom -2003 Honda 300ex

12-14-2003, 07:52 PM	#13
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	i see now that posi and limited slip are the same thing __________________ 70 longbed 496/th400/Ford 9"



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