How do you decode a GM rear end?
The casting numbers are simple to decode. The first letter is the month of the year; A is January, B is February, and so on. The next digit is the day it was built, and the last digit is the year it was built. For example, a 12-bolt axle that was built on March 28, 1967, is C287.
How is GM differential measured?
Measure the ring gear diameter. The ring gear is the largest gear inside the differential housing and normally faces the driver’s-side rear wheel. Using a tape measure or machinist’s ruler, measure the ring gear diameter. This identifies the differential — a Ford 9-inch or GM 7.5-inch — for example.
How are GM gear ratios calculated?
Count the teeth on the small gear in the forward part of the axle housing, called the pinion gear. Count the number of the teeth in the big ring gear attached to the differential. Divide the number of teeth on the pinion into the number of teeth on the ring gear. This is the gear ratio.
How do I identify my Chevy truck rear end?
How to Identify a Chevy Rear End
- Count the number of inspection cover bolts on the rear end housing.
- Identify the most common GM rear-end types.
- Look at the shape of the inspection cover and the gasket.
- Locate the GM manufactured rear-end casting date on the housing.
How long does it take to rebuild a differential?
three to five hours
A complete rear differential replacement includes replacing the housing, gears, bearings, and seals. The average time it takes a certified mechanic to perform a differential rebuild at a shop is usually three to five hours. A rebuild on a commercial vehicle by someone without prior experience could take much longer.
How do I know my GM rear end ratio?
Identify your GMC or Chevrolet rear end gear ratio by the RPO Codes, usually located on the placard labeled “Service Parts Identification” inside the drivers door panel or glove box.
What is the diameter of a GM rear end differential?
General Motors rear end differentials are referred to by the diameter of the ring gear, i.e. 7.5 inch, 8.5 inch, 10.5 inch. Our experts will help you find the correct ring and pinion set for your particular application.
How can you tell if a gear differential is 1-way?
If both ramps of the gear teeth have symmetrical slopes, the differential is a 2-way. If they look like saw-teeth (one vertical, one sloped) then the LSD is a 1-way. If both sides have sloped ramps but are asymmetrical, it is a 1.5-way differential.
What differentials are available on the market?
The available differentials on the market are open, limited-slip, locking, and spool. The axles are tied together permanently with the spool, so technically, it is not a differential at all because there is no differentiating rotation between the axles.
What is the difference between a gear-drive differential and a clutch differential?
When the clutch-type differential chatters and alters the ability to steer the car, such as with a 2-way-clutch LSD, the gear-drive differential does not. Clutch and cone-type differentials are commonly installed in cars from the factory.
