Probably the easiest 12-bolt differentials to find are the type 2 units. These are found primarily in standard-performance Chevrolet passenger cars. Type 2 ratios were somewhere **between 2.29:1 and 2.73:1**.

## How do I know what gear ratio my 12 bolt?

12-bolt axles can be identified by **casting numbers on the bottom of the cast-iron center-section and on the front of the passenger side axle tube**. This identifies the car make and model, gear ratio, date of casting and assembly and factory of origin.

## What ring gear size is a GM 12 Bolt diff?

12-Bolts to Glory The GM 12-bolt debuted in 1965 and was mass-produced until 1972. It features an **8.875-inch** ring-gear carrier held in place with two internal main caps. The pinion gearshaft measures 1.625 inches in diameter and is shimmed to achieve the proper pinion depth.

## What’s better 10 bolt or 12 bolt rear end?

First, the 10-bolt’s pinion shaft diameter is 1.438 (25 splines) while the 12-bolt is 1.625 (30 splines) which makes the **12-bolt 13 percent larger in diameter and therefore stronger**.

## What is a 12 bolt rearend?

The 12-bolt **positions the pinion-gear higher on the ring gear, which reduces the load on the pinion**. This results in less parasitic loss from the friction caused as the gears mesh. Introduced in 1964, the 12-bolt rearend became a staple for Chevrolet racers.

## What size is a GM 12 bolt rear end?

The GM 8.875-inch, 12-bolt positraction came in many 1965 to ’72 passenger cars. The pinion shaft on passenger cars’ differentials was 1.625 inches in diameter, and the cover was oval, measuring **10.9375 inches wide by 10.625 inches tall**.

## How many teeth does 4.10 gears have?

Example: 4.09 / 4.10 / 4.11 Gear Ratios

Axle |
Ring Gear Teeth |
Final Ratio |
---|---|---|

Toyota 8″ | 37 | 4.11 |

Dana 44 | 45 | 4.09 |

Dana 60 | 41 | 4.10 |

GM 10.5″ 14 Bolt | 45 | 4.09 |

## How do I know my diff ratio?

**Rotate the marked tire one revolution while counting how many times the driveshaft rotates**. eg, If your driveshaft made 3 3/4 revolutions, that would determine a 3.73 gear ratio. If you get approximately 2 3/4 revolutions, you have a 2.76 gear ratio.

## How do you find the rpm of a gear ratio?

The general rule is – **large to small gear means ‘multiply’ the velocity ratio by the rpm of the first gear**. Divide 60 teeth by 30 teeth to find the velocity ratio. Multiply this number (2) by the rpm (120). This gives an answer of 240rpm.

## How many quarts is a 12 gauge bolt?

Registered. A 12 bolt should only take around **3 quarts** until it comes out the fill hole.

## What is the difference between a car and truck 12 bolt rear end?

They are two different rear ends, and **the car is better in nearly every way**. If I am not mistaken the 8.5 10 bolt is stronger in more ways too then the truck 12 bolt. The only things that make’s the 8.5″ &

the Car 12-bolt stronger is the larger pinion stem diameter &

only seen one break.

## Did Pontiac make a 12 bolt rear end?

Although Buick, Pontiac and pre-’67 Oldsmobiles used the same basic 8.2-inch 10-bolt differential (**1967-’70 Oldsmobiles used the Olds-specific 12-bolt 8.5-inch differential**), these are different from the Chevrolet 8.2 10-bolt offerings.

## Is posi traction the same as limited slip?

Despite the fact that a lot of folks confuse the terms “posi” or “Positraction” with “limited slip,” the fact is that **the two are basically one and the same**. Today, all positive traction systems are referred to as limited slip systems.

## How much horsepower can a 8.2 10 bolt handle?

Roughly **550 to 600 HP** total. No slicks, drag radials. No problems with the 8.2 at all. I used the stock diff., the Auburn would be better.

## What is the strongest rear end?

**Dana 60** Rear End Assemblies

If you want a big brute of a rear end under your car, look no further than a Dana 60. Even in the heyday of muscle cars, Dana 60 rear differentials were renowned for their strength, along with their difficulty to locate.

## Who makes Chevy rear end?

Rear ends with measurement designations are named after the diameter of the ring gear, i.e. 7.2 and 8.5 inch. As Chevrolet used many different rear-end models throughout the years, casting codes vary in both location and translation. Information given is for **GM-manufactured rear ends**.

## How do you find the gear ratio on a Chevy Silverado?

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 rear end came in a 57 Chevy?

Automatic 57 cars (both 6 and V8) came with 14inch tires and **3:36 rear gears**. Stick shift 57 cars came with 14 inch tires and 3:55 gears.

## How do I identify my GM axle?

Information about Differentials in GM vehicles can usually be obtained by **looking at the RPO or “Regular Production Option” codes contained in the Service Parts Identification tag in the glovebox**. Whenever possible, reference the tag numbers when ordering parts for your Differential.

## How many teeth does 3.55 gears have?

39-11 Teeth

Manufacturer |
Motive Gear |
---|---|

Brand | Motive Gear |

Model | Motive Gear D35-355 Rack and Pinion, 39-11 Teeth, 3.55 Ratio |

Item Weight | 11.44 pounds |

Product Dimensions | 15.5 x 11 x 5.25 inches |

## Are 3.73 or 4.10 gears better?

**4.10 is the typical gear ratio for a high-performance vehicle like a sports car or SUV because it provides better acceleration than 3.73** because of the faster second and third gears, which provide more torque at lower speeds to accelerate from a stop.

## How many teeth does a 3.73 ring have?

Richmond Ring &

Pinion Set – 3.73 Ratio, **41-11 Teeth**, GM 10 Bolt “New Style” (70-94)

## What is the best gear ratio for torque?

indeed Does gear ratio affect horsepower? A higher numeric axle ratio (4.11:1) keeps the engine running in the higher horsepower range, thus improving performance.Are 3.73 or 4.10 gears better?

3.73 Ratio |
4.10 Ratio |
---|---|

Lower Torque | Higher Torque |

Better Gas Mileage | Decreased Gas Mileage |

Higher Top Speed | Lower Top Speed |

## What gear ratio do I have f150?

**Write down the number in the lower left-hand corner of the tag.** **It will look like “3.23” or “3.50.”** This is the gear ratio.

## Can you tell gear ratio from VIN?

**The Vehicle Descriptor Section (VDS) of the VIN will carry information for the gearbox ratio if the specific manufacturer includes it**. If not, you might need to take help from a trusted VIN decoder website or find out manually.

## Which gear has highest speed reduction?

Worm gears are perhaps the most costeffective reduction solution, but usually have a minimum 5:1 ratio and lose considerable efficiency as ratios go higher. **Bevel reducers** are very efficient but have an effective speed reduction upper limit of 6:1.

## What will be the rpm of smaller gear if a 180mm dia meshes with 60 mm dia gear and the bigger gear makes 60rpm?

On substituting respective value in above equation: So: Means speed of smaller gear is **180 RPM**.

## Does gear reduction increase torque?

The rotary machine’s output torque is increased by multiplying the torque by the gear ratio, less some efficiency losses. While **in many applications gear reduction reduces speed and increases torque**, in other applications gear reduction is used to increase speed and reduce torque.