NO LONGER AVAILABLE Listing ended Oct 5, 2026

1978 GMC 2500

$15,500

Vehicle Details

Make

GMC

Model

2500

Year

1978

VIN

AMS22535

Body Type

Pickup Truck

Description

1978 GMC 2500 Blue for sale in Layton.

GMC 2500 Buyer's Guide

Full guide

Robert Halloran

Classic Trucks

1967–1987

~3 min read

Updated Apr 2026

The GMC 2500 three-quarter-ton pickup was the working truck that the C10 half-ton buyers couldn't afford to rely on, heavier springs, stronger axles, and the kind of payload capacity that meant something to buyers who actually needed to haul, not just look good doing it.

This guide covers

✓ 9-point inspection checklist

✓ Common issues & what to avoid

✓ In-person inspection guide

✓ Market pricing by year & condition

✓ 4 FAQs answered

✓ History & fun facts

Read the Full 2500 Buyer's Guide

GMC 2500 Market Overview

Based on 12 GMC 2500 listings currently on ClassicCarsArena.com

Listed Now

$13,029

Avg. Asking Price

1948–1987

Year Range

Price Position on Our Site - Above Average

This car: $15,500

Low: $6,495 High: $28,900

Transmission Distribution

Automatic 58%

Manual 17%

Condition Distribution

Excellent 8%

Good 42%

Fair 8%

Data from ClassicCarsArena.com listings Browse all 12 listings →

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GMC 2500 Buyer's Guide

Robert Halloran here. When I work on a ranch or a farm, everybody knows the difference between a half-ton truck and a three-quarter-ton truck. The three-quarter-ton is the one you hook up to the trailer. The half-ton is what the ranch owner drives to town. The GMC 2500, the three-quarter-ton variant of the C/K series, is a working truck first, and everything about it reflects that purpose.

The square-body era 1973–1987 GMC 2500 has been discovered by the restomod community in recent years, but the honest truck market has always known these were the right trucks to have if you were actually going to use them. Better springs, heavier axle, stiffer frame, the 2500 is the 1500's older, more serious sibling.

What to Check Before Buying

✓

Cab Corner Rust , Probe front cab corners, the primary rust location on all square-body trucks.

✓

Rear Cab Lower Section , Check lower rear cab behind doors, second most common rust location.

✓

Frame Rails , Inspect full frame length for bends and rust at cab mount points, overloaded 2500s can show frame stress.

✓

K2500 4WD Function , Test 4H and 4L engagement on K2500 trucks, listen for grinding or failure to engage.

✓

Front Axle U-Joints , Listen for clicking when turning on 4WD trucks: U-joint wear is common from heavy use.

✓

Transfer Case Leaks , Inspect transfer case output seals, leaks are common on older 4WD trucks.

✓

Small-Block Rear Main Seal , Check under the engine for V8 rear main seal oil leaks, common on high-mileage small blocks.

✓

Transmission Function , Test TH350/TH400 through all ranges, smooth shifts with no slipping.

✓

Bed Floor Condition , Inspect bed floor planks and metal floor structure, working trucks often have bed damage.

Common Issues

Cab corner rust, the most common structural issue on any square-body truck. Frame rust at cab mount points on heavily used 2500s. Front axle U-joint wear on K2500 4WD trucks, clicking in turns. Transfer case oil seal leaks. Small-block V8 rear main seal oil leaks. TH400 band adjustment needed on high-mileage examples. Brake system rubber components deterioration on unrestored examples. Rust in the bed floor from working use. 6.2L diesel injection pump failures on diesel variants.

What to Look For

Front cab corners are the primary rust location on any square-body truck, probe thoroughly before anything else. The lower rear cab behind the doors is the second location. On K2500 4WD trucks, verify the front axle engagement (test 4H and 4L), inspect the front differential for leaks, and check the transfer case operation. The front axle U-joints on 4WD trucks see heavy use and wear, listen for clicking or vibration when turning. On V8 trucks, verify the engine doesn't have the common small-block oil leak at the rear main seal. The TH350/TH400 transmission is durable but check for slipping in any gear. Inspect the frame rails for any bending or cracking at the cab mount points, heavy-use 2500s are occasionally overloaded.

Price Guide

1967–1972 GMC 2500 C (2WD): $14,000–$30,000. 1967–1972 GMC K2500 (4WD): $20,000–$42,000. 1973–1980 GMC 2500 C (2WD): $12,000–$26,000. 1973–1980 GMC K2500 (4WD): $18,000–$38,000. 1981–1987 GMC 2500/K2500: $10,000–$28,000. Sun Belt rust-free examples: 30–45% premium over equivalent northern trucks. Show-quality restorations: $35,000–$60,000.

Did You Know?

The GMC 2500 and the Chevrolet K20/C20 are mechanically identical, the same frame, chassis, engine options, and drivetrain components. The two marques existed as separate distribution channels serving different regional dealer networks, with slightly different styling details (grille, badging, some trim) to justify the name difference. The 1973–1987 square-body design was produced for 15 consecutive years because it was so functionally successful, longer than any other single American truck design of the era.

$15,500