Weak link: Broken transfer case-to-transmission adapters on NP205-equipped vehicles
Models affected: All models equipped with an NP205 transfer case
What happens: The adapters tend to crack or break (shown) due to standard wear and/or improper length front driveshaft that bottoms out under flex and puts pressure on the transfer case.
Sturdy fix: Make sure you have the proper-length driveshaft. It's also important to make sure that the strut rod from the bellhousing to the side of the transfer case be retained to help keep the transfer case from flexing. Often, this part is removed and discarded by the unknowing when swapping transmissions or transfer cases. Off Road Design offers new or used replacement adapters.
Contact: Off Road Design.
Weak link: Rear upper shock-absorber mounts that tear from the frame
Models affected: '73-'91 1/2-ton vehicles What happens: This is a common failure, caused by a number of factors. For those who travel off-highway frequently, the problem is more common, as the shocks are the limiting factor in the rear suspension, causing undue stress at the mount.
Sturdy fix: Steve Frisbie at Missouri Off Road Outfitters says he has successfully welded washers to the inside and outside of the frame, effectively rebuilding the mount. He says he used two different outside diameter washers to eliminate the weak spot in the frame. Missouri Off Road Outfitters also offers a rear bolt-in shock crossmember (shown) that angles the shocks towards the center of the frame and allows increased suspension travel and eliminates the need for the stock mounts.
Contact: Missouri Off Road Outfitters.
THE KING PIN
Weak link: Dana 60 front axle king pins
Models affected: All vehicles with Dana 60 front axles
What happens: The king pins wear, creating "death wobble," as well as other maladies. They will wear even faster if the vehicle is fitted with larger tires.
Sturdy fix: Off Road Design offers a kingpin rebuild kit (shown) or just new kingpin springs and bushings.
Contact: Off Road Design.
Weak link: Front driveshaft length
Models affected: All duty levels, '73-'91
What happens: Steven Watson at Off Road Design says that the front driveshaft is a bit on the short side and with some lift and transmission combinations you can run out of angulation capability. Watson says that this is most common with the TH350/NP205 or the SM465/NP205 combinations with a 6-inch-or-higher suspension lift.
Sturdy fix: The solution is to have a company like Tom Wood's Custom Driveshafts or High Angle Driveline make a shaft with more angulation capability. Another option, if a bit pricy, is to use the Off Road Design Doubler Kit (shown), which moves the NP205 approximately 6 inches to the rear of the vehicle.
Contact: High Angle Driveline, Off Road Design, Tom Wood's Custom Driveshafts.
Weak link: Hood hinge stiffening
Models affected: '73-'80 trucks and SUVs
What happens: The hood hinges stiffen when not lubed regularly, thus requiring more force to close the hood. This pressure on the hood causes it to buckle.
Sturdy fix: Keep the hinges lubricated to keep them from stiffening. If the hinges are already stiff, replace them. They're relatively inexpensive, and easy to install.
Contact: You local GM dealer.
TRIPPY FUSIBLE LINK
Weak link: Firewall-mounted fusible links
Models affected: '73-'91 all duty-level trucks
What happens: The insulation on the fusible links tends to degrade due to close proximity to the exhaust manifold. This can cause the fusible link to trip.
Sturdy fix: Steve Frisbie of Missouri Off Road Outfitters says that he cured this problem by replacing the links with blade-type fuses and holders.
Contact: Do-it-yourself fix.
High Angle Driveline
Off Road Design
Tom Wood's Custom Driveshafts
1025 E. Oleander St.
Off Road Unlimited
Missouri Off Road Outfitters