General Torsen Questions:
Torsen for Ford vehicles:
Torsen for GM vehicles:
General Torsen Questions:
Torque Bias Ratio, represents
the "locking effect" of the differential.
indicates how much more torque is sent to the high traction wheel (or axle)
is sent to the wheel with less traction. For example, a differential
with a TBR of
4:1 sends 4 times the
available torque that
the wheel can maintain. In the example below,
80% of the total
available torque goes to the higher traction,
slower spinning wheel.
This is a complex question, however a paper (re-written in PDF - Portable Document Format) that technically explains how the Torsen T-1 (Type A) differential works can be downloaded by clicking the Traction Control Article hyperlink. This paper was published in 1988 by the Institution of Mechanical Engineers (IMechE) and describes in detail how the Torsen functions. Download it and check it out...
This, by far, is the most commonly asked question. The Torsen differential is simply a torque multiplier that works through the use of friction generated by thrust forces from the internal gearing. It multiplies what torque is available from the wheel that is starting to spin-up or lose traction and sends that available torque, multiplied by the TBR, to the slower turning wheel with the better traction.
As mentioned above, the Torsen differential is a torque multiplier. The Torsen requires some type of resistance or friction in the system to function properly. A wheel in the air provides zero torque or friction on the system and as the Torsen multiplies the available torque, zero, by its TBR, the end result is still zero. In response to this, we developed the Torsen T-2R with pre-load to combat those wheel in the air situations.
We suggest that you follow what is listed in your vehicle's owners manual. We do require that a GL4/GL5 class oil be used for the Torsen T-1. The T-1 requires an oil with extreme pressure additives for optimal function. Torsen works well in either synthetic or mineral base oils!
We do not sell units directly from our manufacturing facility but instead use distributors to get our product directly to the end customer. Prices for Torsen differentials vary based upon each particular application and distributor. We do not set our distributors selling price, so please contact one of them for Torsen pricing. Torsen differentials are warranted against manufacturing defects based upon a stock vehicle under normal driving conditions.
Please contact your point of purchase Torsen approved distributor for relevant warranty information.
Please review your vehicle's owners manual and purchase documentation for important warranty information.
Download the Gleason Power Systems - Torsen Model List for information on those part numbers that begin with the letter M. This document dates back to 1984 and is used for informational purposes only. You will need the Adobe Acrobat Reader to view this document.
Torsen for Ford Vehicles:
The Ranger FX4 Level 2 comes standard equipped with a pre-loaded Torsen T-2. Ranger production units will start with a 9702 serial number. Click on the following hyperlink How do I decipher the Torsen part number? to view an explanation of what information is found in the Torsen part number on a Ranger FX4 differential.
Some of our 975420-0207B models that have been shipped were actually prototypes from a couple years ago. They are functionally the same as the new production parts, but they take a different bearing so some of the Dana 30 & Ranger Dana35 models getting out into the field require the LM102949 (cone) and LM102910 (cup) for installation. In the future when we release the 30 tooth versions of the Dana 30 and (rear) Dana 35 these units will also require this bearing combination.
Torsen for GM vehicles:
GM issued a technical bulletin adding modifier to the rear axle oil. This was done to quiet what we call a "Rusty Screw" noise that we heard in a very small percentage of vehicles. This does not happen in all cases, however to address owner's concerns we asked that the modifier be used in all instances to insure that the driver would not get this noise. When replacing the fluid it is at the owner's discretion whether or not to add the modifier. Elimination of the modifier does not affect durability of the differential.
Those numbers are Torsen part numbers associated with the production 7.6" GM F-Car series (Camaro, Firebird) vehicles. The 9030, 9031 and 9032 numbers refer to the low numeric series or Series 2 axles (2.73, 2.93, and 3.08 rear axle ratios) whereas the 9020, 9021, and 9022 numbers reference the high numeric or Series 3 axles (3.23, 3.42, 3.73, and 4.11 rear axle ratios).
Typical production part numbering sequence on a Torsen differential:
If you have any general questions you would like answered and believe it would benefit others by being posted here, then please feel to send us an e-mail!
Page was last updated March 16, 2010.
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