My Sierra 1500 has rust on rear axle. The differential cover is badly rusted but not leaking. Since the last service everything looked good under the truck. To my surprise when I changed out my shocks recently the undercarriage looked bad. Found out during the last two winters where I reside, the County used liquid salt on the roads. Liquid salt is highly corrosive and has started to eat the frame as well. Most of the rust can be removed from the truck and undercoated again. BUT MY BIGGEST CONCERN IS HOW BADLY DAMAGED CAN THE DIFFERENTIAL HOUSING GET BEFORE REPLACEMENT IS NEEDED?
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Differential Rust
- Thread starter Bushpilot
- Start date
Sorry to hear abt the differentail rusting. It's a bummer when they use corrosive salts on roads.
I know a guy who powder coated his differential cover when he noticed it rusting (his rig did abt 62,0000 miles before he drained the fluid, reinstalled the cover, and refilled it). Could work for you. As for how long a rusting differential will hold, i have no ideas, but it seems the rust issue should be addressed.
I know a guy who powder coated his differential cover when he noticed it rusting (his rig did abt 62,0000 miles before he drained the fluid, reinstalled the cover, and refilled it). Could work for you. As for how long a rusting differential will hold, i have no ideas, but it seems the rust issue should be addressed.
VANHUNTT
I am currently removing as much rust as I can. Then will protect it again after I am satisfied with my results. Just hope the integrity of the differential housing is not compromised! As for the cover it is probably thick enough metal to clean and protect again and reuse. Or will purchase a new cover and maybe new bolts. Thanks for your input. Bushpilot
I am currently removing as much rust as I can. Then will protect it again after I am satisfied with my results. Just hope the integrity of the differential housing is not compromised! As for the cover it is probably thick enough metal to clean and protect again and reuse. Or will purchase a new cover and maybe new bolts. Thanks for your input. Bushpilot
# PI0281D: Underbody Component Corrosion - (Jan 16, 2014)
Subject: Underbody Component Corrosion
Models: 2015 and Prior GM Passenger Cars and Light Duty Trucks
This PI has been revised to add model years. Please discard PI0281C.
The following information may be helpful when addressing underbody component corrosion with customers.
Some customers may comment that one or more of their vehicle's underbody components are showing some form of corrosion.
This corrosion may be red in appearance (rust) if the component is steel, forged iron or cast iron.
This corrosion may also be grey or white in color if the component is constructed of an aluminum alloy.
Note :
Extended outside storage may increase the opportunity for brake rotor rust. Vehicle braking systems tend to be self-cleaning while vehicles are in use, preventing any build-up of corrosion on the brake rotor surfaces. At times more extensive corrosion can cause pulsation due to thickness variation. This usually happens when the vehicle is parked for long periods of time in humid type conditions and the braking surface area under the pads corrode at a different rate compared to the rest of the braking surface area. Cleaning up of braking surfaces (burnishing) can be accomplished by 10-15 moderate stops from 56-64 km/h (35-40 mph) with cooling time between stops. If multiple, moderate braking stops do not correct this condition, refer to the latest version of Corporate Bulletin Number 00-05-22-002 - Disc Brake Warranty Service and Procedures for additional information.
Corrosion Protection
General Motors uses a large variety of materials in the manufacture of vehicles. Many of these components undergo an extensive corrosion protection process. These components include major body structures, powertrain, wiring and electrical components and various other areas of the vehicle. General Motors engineering determines the effects of corrosion on every vehicle component.
Acceptable Corrosion
General Motors has determined that the performance of some components is not affected by surface corrosion and no longer takes preventative steps on these parts.
Rust
This corrosion may be red or brown in appearance if the component is made of steel, forged iron or cast iron.
These are typical underbody or mechanical components such as but not limited to propshafts, propshaft yokes, U-joint, steering knuckles, brake rotors and calipers, axle housings, springs, shock absorbers, suspension control arms, tie rod ends and exhaust system components. As the rust ages, it turns from an orange-red like appearance to a darker brown like appearance.
Aluminum Oxidation
Cast aluminum alloy components may appear to have a grey or white coating on the surface commonly known as "surface oxidation." Uncoated aluminum alloys begin to oxidize as soon as it is exposed to the atmosphere. This coating does not affect the serviceability or performance of the component.
Many mechanical components are cast in aluminum alloys, these components may include, but are not limited to oil pans, valve covers, transmission and transfer case housings, steering gears and axle housings.
Subject: Underbody Component Corrosion
Models: 2015 and Prior GM Passenger Cars and Light Duty Trucks
This PI has been revised to add model years. Please discard PI0281C.
The following information may be helpful when addressing underbody component corrosion with customers.
Some customers may comment that one or more of their vehicle's underbody components are showing some form of corrosion.
This corrosion may be red in appearance (rust) if the component is steel, forged iron or cast iron.
This corrosion may also be grey or white in color if the component is constructed of an aluminum alloy.
Note :
Extended outside storage may increase the opportunity for brake rotor rust. Vehicle braking systems tend to be self-cleaning while vehicles are in use, preventing any build-up of corrosion on the brake rotor surfaces. At times more extensive corrosion can cause pulsation due to thickness variation. This usually happens when the vehicle is parked for long periods of time in humid type conditions and the braking surface area under the pads corrode at a different rate compared to the rest of the braking surface area. Cleaning up of braking surfaces (burnishing) can be accomplished by 10-15 moderate stops from 56-64 km/h (35-40 mph) with cooling time between stops. If multiple, moderate braking stops do not correct this condition, refer to the latest version of Corporate Bulletin Number 00-05-22-002 - Disc Brake Warranty Service and Procedures for additional information.
Corrosion Protection
General Motors uses a large variety of materials in the manufacture of vehicles. Many of these components undergo an extensive corrosion protection process. These components include major body structures, powertrain, wiring and electrical components and various other areas of the vehicle. General Motors engineering determines the effects of corrosion on every vehicle component.
Acceptable Corrosion
General Motors has determined that the performance of some components is not affected by surface corrosion and no longer takes preventative steps on these parts.
Rust
This corrosion may be red or brown in appearance if the component is made of steel, forged iron or cast iron.
These are typical underbody or mechanical components such as but not limited to propshafts, propshaft yokes, U-joint, steering knuckles, brake rotors and calipers, axle housings, springs, shock absorbers, suspension control arms, tie rod ends and exhaust system components. As the rust ages, it turns from an orange-red like appearance to a darker brown like appearance.
Aluminum Oxidation
Cast aluminum alloy components may appear to have a grey or white coating on the surface commonly known as "surface oxidation." Uncoated aluminum alloys begin to oxidize as soon as it is exposed to the atmosphere. This coating does not affect the serviceability or performance of the component.
Many mechanical components are cast in aluminum alloys, these components may include, but are not limited to oil pans, valve covers, transmission and transfer case housings, steering gears and axle housings.
I had to replace all of the brake lines on my GMC Sierra due to serious rust. By serious, I mean two of them burst while I was driving the truck. The fuel lines have also rusted badly, and the frame rails near the back of the truck are looking bad. But, by gosh, there's not a spot of body rust , since that's something that can be easily seen by potential new truck buyers. Apparently, GM can deal with liquid salt if it involves the body , but not anything hidden under the truck.