GMC Jimmy 1970-1991 Drivetrain Specifications
Explore the detailed drivetrain specifications for the 1970-1991 GMC Jimmy, including transmission, transfer case, axles, and differentials. Ideal for maintenance, repairs, and performance upgrades.
Overview Specifications
This document provides detailed specifications and technical information about the drivetrain of the 1970-1991 GMC Jimmy. It is designed to assist enthusiasts, mechanics, and researchers in understanding the components, configurations, and performance characteristics of the vehicle's drivetrain. Use the search and navigation instructions to quickly locate specific details or browse through the sections for a comprehensive overview.
How to Use
Use the search functionality to find specific terms or components by entering keywords related to the drivetrain, such as 'transmission' or 'axle ratio'. Results will highlight relevant sections and subsections.
Navigate through the document by scrolling through the sections or using the table of contents. Each section is organized by major drivetrain components, with subsections providing detailed technical information.
Key Specifications
Engine Options
4.1L I6, 5.0L V8, 5.7L V8
Transmission Options
3-speed manual, 4-speed manual, 3-speed automatic
Transfer Case
Part-time 4x4, 2.03:1 low range
Axle Ratios
3.08, 3.42, 3.73, 4.10
Ground Clearance
8.5 inches
Available Specifications
Engine and Transmission
This section covers the engine configurations and transmission options available for the 1970-1991 GMC Jimmy. It includes details on engine types, horsepower, torque, and transmission models, as well as their compatibility and performance characteristics.
Engine and Transmission
This section covers the engine configurations and transmission options available for the 1970-1991 GMC Jimmy. It includes details on engine types, horsepower, torque, and transmission models, as well as their compatibility and performance characteristics.
Engine Options
- Base engine: 4.1L inline-6 (250 CID)
- Optional engine: 5.0L V8 (305 CID)
- Optional engine: 5.7L V8 (350 CID)
- Horsepower range: 110-210 HP
- Torque range: 200-300 lb-ft
- Fuel delivery: Carbureted
Transmission Options
- 3-speed manual transmission (standard)
- 4-speed manual transmission (optional)
- 3-speed automatic transmission (optional)
- Transfer case: Part-time 4x4 system
- Gear ratios: Vary by model year and configuration
Transfer Case and Driveline
This section provides information on the transfer case and driveline components, including their design, operation, and specifications. It covers the 4x4 system, drive modes, and driveline configurations.
Transfer Case and Driveline
This section provides information on the transfer case and driveline components, including their design, operation, and specifications. It covers the 4x4 system, drive modes, and driveline configurations.
Transfer Case
- Type: Part-time 4x4
- Shift mechanism: Manual lever
- Low-range gear ratio: 2.03:1
- High-range gear ratio: 1:1
- Compatibility: Matched with manual and automatic transmissions
Driveline Components
- Front axle: Solid Dana 44
- Rear axle: Solid 12-bolt GM
- Axle ratios: 3.08, 3.42, 3.73, or 4.10
- Drive shafts: Two-piece design with center support bearing
- U-joints: Heavy-duty for off-road use
Suspension and Steering
This section details the suspension and steering systems that support the drivetrain. It includes information on front and rear suspension types, steering mechanisms, and their impact on drivetrain performance.
Suspension and Steering
This section details the suspension and steering systems that support the drivetrain. It includes information on front and rear suspension types, steering mechanisms, and their impact on drivetrain performance.
Suspension System
- Front suspension: Solid axle with leaf springs
- Rear suspension: Solid axle with leaf springs
- Shock absorbers: Hydraulic, front and rear
- Ground clearance: 8.5 inches (varies by model year)
- Weight distribution: 55% front, 45% rear
Steering System
- Type: Recirculating ball steering
- Steering ratio: 24:1
- Power steering: Optional on later models
- Turning radius: 42 feet
- Steering linkage: Heavy-duty for off-road durability
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Component Specifications
Overview
- Type
- 4x4 part-time or 2WD
- Configuration
- Front-engine, rear-wheel drive or four-wheel drive
- Platform
- GM K5 Blazer/Jimmy platform
- Material
- Steel and cast iron
- Location
- Longitudinal placement under chassis
Dimensions
- Driveshaft Length
- 52.5 inches (133.4 cm)
- Transfer Case Width
- 14.2 inches (36.1 cm)
- Axle Width Front
- 65.5 inches (166.4 cm)
- Axle Width Rear
- 65.5 inches (166.4 cm)
- Ground Clearance
- 8.5 inches (21.6 cm)
- Transmission Length
- 28.3 inches (71.9 cm)
- Differential Gear Ratio
- 3.08:1 or 3.73:1 (optional)
Materials
- Driveshaft
- High-strength steel
- Transfer Case
- Cast iron housing
- Axles
- Forged steel
- Differential
- Cast iron housing with steel gears
Features
- Transmission
-
- 3-speed manual (standard)
- 4-speed manual (optional)
- 3-speed automatic (optional)
- Transfer Case
-
- Part-time 4WD
- Manual shift lever
- 2-speed reduction
- Axles
-
- Dana 44 front axle
- Corporate 12-bolt rear axle
- Limited-slip differential (optional)
- Suspension
-
- Front solid axle with leaf springs
- Rear solid axle with leaf springs
- Heavy-duty shock absorbers
- Brakes
-
- Front disc brakes (optional)
- Rear drum brakes
- Hydraulic brake system
Safety Features
- Braking
-
- Dual-circuit hydraulic brakes
- Parking brake system
- Stability
-
- Heavy-duty chassis
- Reinforced axle housings
- Control
-
- Manual locking hubs
- Steering stabilizer
Comfort Features
- Noise Reduction
-
- Insulated transmission tunnel
- Rubber-mounted drivetrain components
- Vibration Control
-
- Balanced driveshaft
- Heavy-duty engine mounts
- Handling
-
- Power steering (optional)
- Stabilizer bar (optional)
Accessories
- Off Road
-
- Skid plates
- Heavy-duty tow hooks
- Winch-ready bumper
- Performance
-
- Upgraded differential covers
- High-capacity transfer case
- Reinforced driveshaft
- Utility
-
- Trailer hitch
- Heavy-duty leaf springs
- Extended-range fuel tank
Maintenance
- Service interval
- Every 30,000 miles or 24 months
- Service Items
-
- Check and refill differential fluid
- Inspect driveshaft U-joints
- Lubricate transfer case
- Inspect axle seals
- Check transmission fluid level
- Maintenance Notes
- Regularly inspect for leaks and wear on drivetrain components, especially in off-road conditions.
Warranty
- Basic
- Miles: 12,000Years: 1Coverage: Defects in materials and workmanship
- Powertrain
- Miles: 50,000Years: 5Coverage: Transmission, transfer case, and axles
- Corrosion
- Miles: UnlimitedYears: 6Coverage: Perforation from rust
- Emissions
- Miles: 50,000Years: 5Coverage: Emission control components
Production Details
- Manufacturer
- General Motors
- Manufacturing Process
-
- Casting for transfer case and differential housings
- Forging for axle shafts
- Machining for gear components
- Quality Control
- inspection: Dimensional checks on all componentsTesting: Durability testing under load conditionsStandards: GM internal quality standards
- Sustainability
-
- Recycled steel used in drivetrain components
- Efficient machining processes to reduce waste
- Production Metrics
- Units Per Day: Approximately 200Lead Time: 2-3 weeks for drivetrain assembly
Service Information for drivetrain Service
Maintenance and service requirements specific to the drivetrain
- Inspect and lubricate U-joints
- Check differential fluid levels
- Inspect transfer case for leaks
- Test 4WD engagement
- Inspect axle seals
Ensure all fluids are topped off and replace if contaminated.
- Replace differential fluid
- Inspect driveshaft for balance
- Check transmission mounts
- Test parking brake system
- Inspect brake lines and hoses
Use manufacturer-recommended fluids for replacements.
- Rebuild or replace U-joints
- Inspect and replace worn axle bearings
- Check transfer case shift linkage
- Perform transmission flush
- Inspect and replace worn brake components
Consider replacing seals and gaskets during major service intervals.
Frequently Asked Questions
Find answers to common questions about torque specifications
Q1 What drivetrain components are compatible with the 1970-1991 GMC Jimmy?
What drivetrain components are compatible with the 1970-1991 GMC Jimmy?
The 1970-1991 GMC Jimmy typically features a 4x4 drivetrain with a Dana 44 front axle and a GM 12-bolt rear axle. It is compatible with engines like the 4.1L inline-6, 5.0L V8, and 5.7L V8. Transmission options include the TH350 and TH400 automatic transmissions. Always verify compatibility with your specific model year and configuration before purchasing replacement parts.
Q2 What are the maintenance requirements for the GMC Jimmy's drivetrain?
What are the maintenance requirements for the GMC Jimmy's drivetrain?
Regular maintenance for the GMC Jimmy's drivetrain includes checking and replacing differential fluid every 30,000 miles, inspecting U-joints and CV joints for wear, and ensuring proper lubrication of the transfer case. Additionally, inspect the driveshaft for balance and alignment issues. Regular greasing of suspension components and checking for leaks in the transmission and transfer case are also recommended.
Q3 How do I replace the transfer case in a 1970-1991 GMC Jimmy?
How do I replace the transfer case in a 1970-1991 GMC Jimmy?
To replace the transfer case, first, disconnect the battery and drain the transfer case fluid. Remove the driveshafts, shift linkage, and wiring harness connected to the transfer case. Support the transmission with a jack, unbolt the transfer case, and carefully lower it. Install the new transfer case by reversing the steps, ensuring proper alignment and torque specifications for all bolts. Refill with the recommended fluid.
Q4 What should I do if my GMC Jimmy's drivetrain is making unusual noises?
What should I do if my GMC Jimmy's drivetrain is making unusual noises?
Unusual noises from the drivetrain may indicate worn U-joints, a failing transfer case, or differential issues. Start by inspecting the U-joints for play or damage. Check the transfer case and differential fluid levels and condition. If the noise persists, inspect the driveshaft for balance issues or damage. Consult a professional mechanic if the problem cannot be identified or resolved.
Q5 How can I optimize the performance of my GMC Jimmy's drivetrain?
How can I optimize the performance of my GMC Jimmy's drivetrain?
To optimize drivetrain performance, consider upgrading to high-performance U-joints, a heavy-duty driveshaft, and synthetic lubricants for the differential and transfer case. Ensure proper alignment and balance of the driveshaft. Regularly inspect and maintain all components to prevent wear and tear. Additionally, consider installing a limited-slip differential for improved traction and handling.
Factory Service Resources
Access official service manuals, technical documents, and repair guides. These resources provide detailed procedures, specifications, and diagrams directly from the manufacturer.
1970-1991 GMC Jimmy Service Manual
Coming SoonComprehensive guide covering drivetrain maintenance, repair, and troubleshooting for the 1970-1991 GMC Jimmy.
Technical Service Bulletin: Drivetrain Updates
Coming SoonOfficial bulletin detailing updates and fixes for common drivetrain issues in the 1970-1991 GMC Jimmy.
GMC Jimmy Parts and Accessories Catalog
Coming SoonCatalog listing OEM and aftermarket parts for the 1970-1991 GMC Jimmy, including drivetrain components.
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Technical Information
- All specifications, including torque values, fluid capacities, and maintenance procedures, should be verified against your vehicle's factory service manual.
- Vehicle specifications and procedures may vary by model year, trim level, and region.
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