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8.5" & 8.6" GM 30 Spline (Large Journal) Nitro Helix Helical Gear Posi
8.5" & 8.6" GM 30 Spline (Large Journal) Nitro Helical Type Limited-Slip Differential

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Price: $610.93

Product Code: TORS-GM8.5-30

Description Vehicle Applications Warranty Information

GM 8.5" & 8.6"
Nitro Helix Helical Worm Gear Limited-Slip Differential

1991-1996 Chevrolet Caprice
1994-1996 Impala SS
1988-1998 Chevrolet 1/2 Ton Pickup C/K1500
1988-1998 GMC 1/2 Ton Pickup C/K1500
1988-1991 Chevrolet Blazer R/V1500 (Suitable for both front & rear differentials)
1988-1991 GMC Jimmy R/V1500 (Suitable for both front & rear differentials)
1992-1994 Chevrolet Blazer
1988-1991 Chevrolet Suburban R/V1500 (Suitable for both front & rear differentials)
1995-2014 Chevrolet Tahoe
1992-2014 GMC Yukon
1999-2014 GMC Yukon Denali
1992-2014 Chevrolet Suburban
1999-2014 Cadillac Escalade
2002-2011 Cadillac Escalade EXT
2000-2014 GMC Yukon XL 1500
1999-2015 GMC Sierra 1500 (Not 1500HD)
1999-2015 Chevrolet SIlverado 1500 (Not 1500HD)
2002-2006 Chevrolet Avalanche 1500
2002-2006 Chevrolet Trailblazer EXT
2002-2006 GMC Envoy XL
2005-2006 GMC Envoy Denali XL
2004-2008 Buick Rainier w/ 5.3L
2003-2008 Isuzu Ascender w/ 5.3L
2005-2008 Saab 9-7x w/ 5.3L

Differential: GM 8.5" & 8.6" Rear (Large Journal)
Gear Ratio: 2.73 & up
Axle Splines: 30
Ring Gear Bolts: 10 (not included)
Manufacturer: Nitro Gear & Axle
Warranty: 1 Year

You'll want to check out this article on Overland Journal/Expedition Portal about the benefits of installing a Nitro locker.

The Nitro Helical Worm Gear is a torque-sensitive mechanical limited-slip differential that uses worm gears and spur gears to dispense and distinguish input power between two drive wheels or front and back axles. This is a completely separate design from the common beveled spider gear designs seen in most of the automotive industry.

Just like any LSD, the Nitro Helical Worm Gear functions as a standard or open differential under normal driving conditions, allowing one wheel to spin faster or slower as necessary. When a wheel experiences a loss of traction, the gear separation forces start to take effect and distributes the torque to the high-traction wheel by increasing the helical-shaped gears mesh force until wheel spin is reduced or entirely stopped. Once the vehicle exits the low traction condition, the differential resumes normal operation.

What nice about the operation of a Nitro Helical Worm Gear LSD, is its characteristics; smooth, quiet and automatic. This LSD will engage without any driver awareness or require any action. It also has no wearable components and requires no maintenance, producing less time on the rack and more on the road.

Nitro Gear & Axle strives to provide the highest quality differential & axle components available. We take the steps necessary to ensure our parts are dependable. Our product range is continually growing to meet the needs of consumers for new ratios and Fits. At Nitro we know differentials, and know what it takes to provide you with high quality components.

Nitro Gear and Axle Premium Differential Ring and Pinion Gears, Axles and parts


This product can expose you to chemicals including toluene and benzene, which are known to the State of California to cause cancer and birth defects or other reproductive harm.
For more information go to: www.P65Warnings.ca.gov

  • Limited-slip operation
  • Helical-style pinion gears
  • Maintenance free
  • No additive required
  • No Clutches or cones to wear out
  • Smooth/Great traction improvement even over an OEM LSD
  • 1 Year Warranty*
Average Rating: Average Rating: 5 of 5 5 of 5 Total Reviews: 1 Write a review »

  0 of 0 people found the following review helpful:
5 of 5 Much better than GM's stock grenade locker October 31, 2018
Reviewer: Brandon from Wenatchee, WA United States  
The guys at JT's hooked me up with this in my Silverado. I was weary of going with another limited slip after having 2 separate GM rear ends fail, but Al at JT's explained there are no clutches with the worm gear. Not knowing much about differentials myself, I did some YouTube watching and found that the worm gear posit limited slip engages through a series of gears, NOT by clutches or a fraction plate. This means 2 things. One: you do not have to worry about the mechanical parts failing under normal use and proper care. Two: your rear wheels will lock the instant you lose traction, not shortly after like with the GM stock or other clutch engaged LSD's. All in all, this is worth the upgrade over stock replacement, especially in the case of the GM grenade locker.

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