1987 GMC S15 Check Fluid Level Manual Transmission

The 1987 GMC S15 features a manual transmission that requires regular fluid level checks to ensure proper operation and longevity. This guide covers safety precautions, fluid specifications, checking procedures, filling instructions, and troubleshooting for the manual transmission system. Proper maintenance is essential for smooth shifting and transmission protection.

1. Safety Precautions 2. Required Tools and Materials 3. Fluid Specifications 4. Locating Transmission Components 5. Checking Fluid Level Procedure 6. Adding Transmission Fluid 7. Common Symptoms of Low Fluid 8. Maintenance Schedule 9. Troubleshooting 10. Technical Specifications

Safety Precautions

Always work on a level surface and engage parking brake. Allow transmission to cool before checking fluid. Wear protective gloves and eyewear.

Park vehicle on level ground and set parking brake.
Allow transmission to cool to avoid burns from hot components.
Use wheel chocks for additional safety when working underneath vehicle.
Keep ignition off and transmission in neutral during inspection.

WARNING! Hot transmission fluid can cause severe burns. Never work under vehicle without proper support.

Required Tools and Materials

Item	Purpose
Transmission fluid	GM-approved manual transmission fluid
Fluid pump or funnel	For adding fluid through fill port
Clean rags	For cleaning area around fill plug
Socket set	For removing fill/drain plugs
Jack and jack stands	For vehicle elevation (if needed)
Safety glasses	Eye protection
Gloves	Hand protection

Fluid Specifications

Fluid Type: GM Manual Transmission Fluid or equivalent
Capacity: Approximately 3.5 quarts (3.3 liters)
Viscosity: SAE 75W-90 GL-4
Alternative: Dexron III Automatic Transmission Fluid (if specified)
Color: Light amber when new, darkens with age
Change Interval: Every 30,000 miles or 2 years

CAUTION! Use only recommended fluids. Incorrect fluid can damage transmission synchronizers.

Locating Transmission Components

The manual transmission is located between the engine and driveshaft. Key components for fluid service:

Fill Plug: Located on driver's side of transmission case
Drain Plug: Located at bottom of transmission case
Transmission Case: Aluminum housing containing gears
Shift Linkage: Connected to top of transmission

Tip: Clean area around fill plug before removal to prevent contamination.

Checking Fluid Level Procedure

Proper fluid level is crucial for transmission operation.

Park vehicle on level surface and engage parking brake
Clean area around transmission fill plug
Remove fill plug using appropriate socket
Insert finger into fill hole - fluid should be at bottom of hole
If fluid drips out, level is adequate
If no fluid present, add fluid until it begins to overflow
Reinstall and tighten fill plug securely

WARNING! Transmission must be level for accurate fluid level check.

Adding Transmission Fluid

Use proper technique to avoid overfilling or contamination.

Position fluid pump or funnel at fill opening
Slowly add recommended transmission fluid
Pause periodically to check level
Stop adding when fluid begins to overflow from fill hole
Allow excess to drain, then reinstall fill plug
Tighten plug to manufacturer specification (typically 15-20 ft-lbs)
Wipe away any spilled fluid

CAUTION! Overfilling can cause fluid leaks and seal damage.

Common Symptoms of Low Fluid

Symptom	Description
Difficulty shifting	Hard to engage gears, grinding noises
Transmission noise	Whining or grinding sounds in neutral
Gear slippage	Gears pop out of engagement
Overheating	Transmission gets excessively hot
Fluid leaks	Visible fluid on ground under transmission

Maintenance Schedule

Monthly: Visual inspection for leaks
Every 6 months: Check fluid level and condition
30,000 miles: Fluid change
60,000 miles: Complete transmission service
As needed: Top up fluid if low

Note: Severe service conditions may require more frequent maintenance.

Troubleshooting

Problem	Possible Cause	Solution
Hard shifting	Low fluid level	Check and add fluid as needed
Transmission noise	Worn bearings or low fluid	Check fluid level; inspect for wear
Fluid leaks	Worn seals or loose plugs	Tighten plugs; replace seals if necessary
Gear grinding	Incorrect fluid type	Drain and refill with correct fluid
Overheating	Low fluid or heavy use	Check level; allow transmission to cool

Technical Specifications

Transmission Model: Borg-Warner T5 5-speed manual
Fluid Capacity: 3.5 quarts (3.3 liters)
Fill Plug Torque: 18 ft-lbs (24 Nm)
Drain Plug Torque: 20 ft-lbs (27 Nm)
Fluid Type: GM Manual Transmission Fluid or GL-4 75W-90
Service Interval: 30,000 miles or 2 years
Operating Temp Range: -40°F to 300°F (-40°C to 149°C)

Service Information: Contact GM customer service at 1-800-462-8782 for technical support.