1991 Ford LNT9000

Introduction:

The 1991 Ford LNT9000 was a heavy-duty truck that offered a range of engine and transmission options. It was praised for its powerful engines and sturdy construction. However, like any vehicle, it had its share of issues.

Engine

7.3L International DT466

• Cylinder head warping: Symptoms include overheating, coolant leaks, and loss of compression. Solution: Replace cylinder head. Estimated Cost to Fix: $2,000 - $3,000+
• Turbocharger failure: Symptoms include loss of power, black smoke from exhaust, and loud whistling noise. Solution: Replace turbocharger. Estimated Cost to Fix: $1,500 - $2,000+

8.3L Cummins NTC290

• Fuel injector failure: Symptoms include hard starting, poor idling, and black smoke from exhaust. Solution: Replace fuel injectors. Estimated Cost to Fix: $1,000 - $1,500+
• Transmission cooler line leaks: Symptoms include transmission fluid leaks and overheating transmission. Solution: Replace transmission cooler lines. Estimated Cost to Fix: $500 - $1,000+

Transmission

Eaton Fuller 9-speed

• Gearshift linkage failure: Symptoms include difficulty shifting gears or gears popping out of place. Solution: Replace gearshift linkage. Estimated Cost to Fix: $500 - $1,000+
• Synchronizer failure: Symptoms include grinding noises when shifting gears. Solution: Replace synchronizers. Estimated Cost to Fix: $1,000 - $2,000+

Eaton Fuller 10-speed

• Input shaft bearing failure: Symptoms include noise and vibration from transmission. Solution: Replace input shaft bearing. Estimated Cost to Fix: $1,500 - $2,000+
• Transmission case cracking: Symptoms include transmission fluid leaks and loss of gears. Solution: Replace transmission case. Estimated Cost to Fix: $3,000 - $4,000+

Suspension

• Leaf spring breakage: Symptoms include sagging or uneven ride height. Solution: Replace leaf springs. Estimated Cost to Fix: $500 - $1,000+ per leaf spring
• Shock absorber failure: Symptoms include poor ride quality and reduced handling. Solution: Replace shock absorbers. Estimated Cost to Fix: $200 - $400+ per shock absorber

Electrical

• Alternator failure: Symptoms include dim headlights, battery drain, and dashboard warning lights. Solution: Replace alternator. Estimated Cost to Fix: $500 - $1,000+
• Wiring harness damage: Symptoms can vary depending on the location of the damage. Solution: Repair or replace wiring harness. Estimated Cost to Fix: $500 - $2,000+

Exterior

• Hood latch failure: Symptoms include difficulty opening or closing the hood. Solution: Replace hood latch. Estimated Cost to Fix: $100 - $200+
• Door handle breakage: Symptoms include difficulty opening or closing doors. Solution: Replace door handles. Estimated Cost to Fix: $100 - $200+ per door

Interior

• Dashboard lights flickering: Symptoms include intermittent failure of dashboard lights. Solution: Replace faulty bulbs or repair electrical connections. Estimated Cost to Fix: $100 - $500+
• Heater/AC blower motor failure: Symptoms include lack of heat or air conditioning. Solution: Replace blower motor. Estimated Cost to Fix: $200 - $400+

Summary

The 1991 Ford LNT9000 was a capable heavy-duty truck, but it was not without its issues. The most common problems involved engine and transmission components, which could be costly to repair. Other issues with the suspension, electrical, exterior, and interior were less severe and typically less expensive to fix.