GMC Jimmy 1970-1991 TH350 Transmission Specifications
This document provides detailed specifications for the TH350 automatic transmission used in the 1970-1991 GMC Jimmy. It includes essential technical details such as gear ratios, torque converter specifications, fluid capacity, and shift patterns. These specifications are crucial for owners, mechanics, and enthusiasts looking to understand, maintain, or repair the TH350 transmission. The information is valuable for diagnosing issues, performing upgrades, or ensuring compatibility with other components. Whether you're restoring a classic GMC Jimmy or optimizing its performance, this guide serves as a reliable resource for accurate and comprehensive transmission data.
Overview Specifications
This document provides detailed specifications and technical information about the TH350 transmission used in the 1970-1991 GMC Jimmy. It is designed to help enthusiasts, mechanics, and owners understand the features, maintenance, and performance of this transmission. Use this guide to explore its design, capabilities, and key specifications. The document is organized into sections for easy navigation and includes a quick reference for essential details.
How to Use
Use the search function to find specific terms or topics within the document. Enter keywords related to the TH350 transmission, such as 'gear ratios' or 'fluid capacity,' to quickly locate relevant information.
Navigate through the document by scrolling through sections or using the table of contents. Each section is labeled clearly, and subsections provide detailed technical points for easy reference.
Key Specifications
Transmission Type
3-Speed Automatic
Fluid Capacity
10 Quarts
First Gear Ratio
2.52:1
Reverse Gear Ratio
2.07:1
Compatible Engines
GM V8
Available Specifications
Design and Features
This section covers the design elements and key features of the TH350 transmission. Learn about its construction, materials, and the engineering principles that make it a reliable choice for the GMC Jimmy.
Design and Features
This section covers the design elements and key features of the TH350 transmission. Learn about its construction, materials, and the engineering principles that make it a reliable choice for the GMC Jimmy.
Transmission Construction
- Three-speed automatic transmission
- Cast iron main case with aluminum extension housing
- Hydraulic control system for smooth shifting
- Planetary gearset for durability
- Torque converter lock-up feature
- Compact design for easy installation
Performance Features
- Optimized gear ratios for off-road capability
- Heavy-duty clutch packs for towing
- Efficient cooling system for extended use
- Compatible with GM V8 engines
- Low maintenance requirements
- Reliable performance in various driving conditions
Technical Specifications
This section provides detailed technical specifications for the TH350 transmission. Explore gear ratios, fluid capacities, and other critical data to understand its performance and maintenance needs.
Technical Specifications
This section provides detailed technical specifications for the TH350 transmission. Explore gear ratios, fluid capacities, and other critical data to understand its performance and maintenance needs.
Gear Ratios
- First gear: 2.52:1
- Second gear: 1.52:1
- Third gear: 1.00:1
- Reverse gear: 2.07:1
- Optimized for torque and acceleration
- Smooth shifting between gears
Fluid and Capacity
- Transmission fluid type: Dexron II or III
- Fluid capacity: 10 quarts (including torque converter)
- Recommended fluid change interval: 30,000 miles
- Fluid pan gasket material: Rubber or cork
- Filter replacement during fluid changes
- Proper fluid level for optimal performance
Maintenance and Troubleshooting
This section offers guidance on maintaining and troubleshooting the TH350 transmission. Learn about common issues, maintenance tips, and how to ensure longevity and reliability.
Maintenance and Troubleshooting
This section offers guidance on maintaining and troubleshooting the TH350 transmission. Learn about common issues, maintenance tips, and how to ensure longevity and reliability.
Routine Maintenance
- Regular fluid and filter changes
- Inspect for leaks around seals and gaskets
- Check transmission mount for wear
- Monitor shift quality and responsiveness
- Ensure proper fluid level
- Inspect cooling lines for damage
Common Issues and Solutions
- Slipping gears: Check fluid level and condition
- Delayed engagement: Inspect valve body and seals
- Overheating: Verify cooling system functionality
- Fluid leaks: Replace worn seals and gaskets
- Harsh shifting: Adjust throttle linkage
- No reverse gear: Inspect reverse clutch pack
Search Specifications
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Transmission Specifications
Overview
- Type
- Automatic
- Configuration
- 3-speed
- Platform
- GM Turbo Hydra-Matic
- Material
- Aluminum casing with steel internals
- Location
- Rear-wheel drive
Dimensions
- Length
- 21.75 inches / 552.45 mm
- Width
- 13.5 inches / 342.9 mm
- Height
- 13.75 inches / 349.25 mm
- Weight
- 130 lbs / 58.97 kg
- input Shaft Diameter
- 0.75 inches / 19.05 mm
- Output Shaft Diameter
- 1.0 inches / 25.4 mm
- Bellhousing Diameter
- 12.5 inches / 317.5 mm
Materials
- Casing
- Aluminum alloy
- Gears
- Hardened steel
- Clutch Packs
- Steel with friction material
- Seals
- Viton rubber
- Fluid
- Dexron III automatic transmission fluid
Features
- Shifting
-
- Hydraulic control
- Smooth gear transitions
- Manual low gear selection
- Durability
-
- Robust clutch design
- High-strength gears
- Heat-resistant seals
- Performance
-
- Efficient torque converter
- Quick response to throttle input
- Optimized gear ratios
- Cooling
-
- Integrated fluid cooler
- Efficient heat dissipation
- Continuous fluid circulation
- Compatibility
-
- Fits multiple GM models
- Supports various engine sizes
- Easy integration with transfer cases
Safety Features
- Fail-Safes
-
- Neutral safety switch
- Reverse lockout
- Protection
-
- Overheat protection
- Fluid level sensor
- Controls
-
- Parking pawl
- Shift interlock
Comfort Features
- Operation
-
- Quiet shifting
- Smooth acceleration
- Minimal vibration
- Control
-
- Ergonomic shifter
- Clear gear indicators
- Easy maintenance access
Accessories
- installation
-
- Mounting brackets
- Transmission crossmember
- Shift linkage
- Performance
-
- High-capacity cooler
- Upgraded torque converter
- Shift kit
- Maintenance
-
- Fluid pump
- Filter kit
- Seal kit
Maintenance
- Service interval
- Every 30,000 miles / 24 months
- Service Items
-
- Fluid and filter replacement
- Seal inspection
- Clutch pack check
- Shift linkage adjustment
- Torque converter inspection
- Notes
- Use Dexron III fluid for optimal performance
Warranty
- Basic
- Miles: 12,000Years: 1Coverage: Manufacturer defects
- Powertrain
- Miles: 36,000Years: 3Coverage: Transmission components
- Corrosion
- Miles: 50,000Years: 5Coverage: Casing and seals
- Terms
- Warranty void if improper fluid used
Production Details
- Manufacturer
- General Motors
- Manufacturing Process
-
- Precision machining
- Heat treatment
- Assembly line integration
- Quality Control
- Testing: Hydraulic pressure testinginspection: Dimensional accuracy checksCertification: GM quality standards
- Sustainability
-
- Recycled aluminum usage
- Efficient manufacturing waste management
- Production Metrics
-
- Annual output: 500,000 units
- Defect rate: <0.5%
- Production time: 2 hours per unit
Service Information for th350 transmission Service
Maintenance and service requirements specific to this component
- Fluid and filter replacement
- Seal inspection
- Shift linkage adjustment
- Clutch pack check
Use Dexron III fluid only
- Torque converter inspection
- Full system flush
- Valve body check
- Cooler line inspection
Inspect for leaks and wear
- Clutch pack replacement
- Seal replacement
- Full transmission overhaul
- Performance testing
Consider professional service for major overhaul
Common Questions
Find answers to common questions about torque specifications
Q1 What vehicles are compatible with the TH350 transmission for 1970-1991 GMC Jimmy?
What vehicles are compatible with the TH350 transmission for 1970-1991 GMC Jimmy?
The TH350 transmission is compatible with 1970-1991 GMC Jimmy models and other GM vehicles from the same era, including Chevrolet and Oldsmobile. It is designed for rear-wheel-drive applications and supports engines with up to 350 cubic inches. Verify your vehicle's engine size, bolt pattern, and drivetrain configuration for compatibility.
Q2 What maintenance does the TH350 transmission require?
What maintenance does the TH350 transmission require?
Regular maintenance for the TH350 includes checking and changing the transmission fluid every 30,000 miles, inspecting the filter, and ensuring the shift linkage is properly adjusted. Monitor for leaks, unusual noises, or slipping gears. Regular servicing extends the lifespan and maintains optimal performance.
Q3 How do I install or replace the TH350 transmission in a 1970-1991 GMC Jimmy?
How do I install or replace the TH350 transmission in a 1970-1991 GMC Jimmy?
To install or replace the TH350 transmission, start by disconnecting the battery, driveshaft, and transmission cooler lines. Remove the crossmember and unbolt the transmission. Align the new TH350 with the engine, secure it, and reconnect all components. Fill with the correct fluid and test for proper operation.
Q4 What are common issues with the TH350 transmission and how can I troubleshoot them?
What are common issues with the TH350 transmission and how can I troubleshoot them?
Common issues include slipping gears, delayed shifts, and fluid leaks. Check fluid levels and condition first. Inspect the vacuum modulator, shift linkage, and seals. If problems persist, consult a professional for internal component inspection, such as the torque converter or valve body.
Q5 How can I optimize the performance of the TH350 transmission?
How can I optimize the performance of the TH350 transmission?
Optimize performance by upgrading to a high-performance torque converter, adding a transmission cooler, and using high-quality synthetic fluid. Adjust the shift points and ensure the throttle valve cable is properly calibrated. Regular maintenance and avoiding excessive load also enhance longevity and efficiency.
Factory Service Resources
Access official service manuals, technical documents, and repair guides. These resources provide detailed procedures, specifications, and diagrams directly from the manufacturer.
TH350 Transmission Service Manual
Coming SoonDetailed guide covering installation, maintenance, and troubleshooting for the TH350 transmission.
TH350 Technical Service Bulletin
Coming SoonLatest updates and technical information for the TH350 transmission, including common issues and fixes.
TH350 Parts and Accessories Catalog
Coming SoonComprehensive catalog of replacement parts and performance upgrades for the TH350 transmission.
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Important information about using this content
Always refer to your vehicle's service manual and take appropriate safety precautions when performing any maintenance or repairs.
General Information
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The content on this website is provided "as is" without any representations or warranties, express or implied. We make no representations or warranties regarding the accuracy, completeness, or availability of the information.
We shall not be liable for any direct, indirect, special, or consequential damages arising from the use of information on this website.
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.
- Always follow the manufacturer's recommended procedures and safety precautions.
- Working on vehicles can be dangerous. Always take proper safety precautions and use appropriate safety equipment.
- If you're unsure about any procedure, consult a qualified professional mechanic.
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