How to Ship Car Parts: Packing, Limits and Freight

By the ParcelPath Editorial Team · Updated October 2026

To ship car parts, weigh and measure the packed part first: anything up to 70 pounds can go USPS, anything up to 150 pounds and 165 inches in length plus girth can go UPS, and engines, transmissions and other heavy parts go on a pallet by LTL freight. Drain and clean every part that held fuel, oil or coolant, pack it in a double-wall box or crate so it can’t shift, and buy a discounted label instead of paying retail.

Should Your Car Part Ship as a Parcel or as Freight?

Start with the packed weight and dimensions, because they decide everything else. Most alternators, brake parts, sensors, headlights and single tires ship as ordinary parcels, while engine blocks, transmissions, differentials and bulky body panels exceed parcel limits or become too expensive to send that way.

If you aren’t sure how much a part weighs before you pull it, the guide to how much a transmission weighs gives typical weights by type. Tire sets have their own considerations, covered in the guide to the best way to ship wheels and tires.

What Do You Need Before Shipping Car Parts?

• An accurate weight and outside dimensions of the packed part. Carriers re-measure, and a corrected weight or size is billed after the fact.
• A double-wall corrugated box for parcels, or a pallet and crating materials for freight.
• Degreaser, rags and plastic bags to clean the part and contain residue.
• Port caps, tape and stretch wrap to seal openings and protect machined surfaces and threads.
• Dense foam, cardboard inserts or wood blocking to immobilize the part.
• A shipping label and printer, or a printer-free option such as a UPS Mobile Barcode or USPS Label Broker code.
• The part’s value, so you can add insurance coverage for expensive components.

Which Car Parts Are Restricted or Hazardous?

Car parts are where shippers most often run into hazardous materials rules. USPS treats anything that has held fuel as potentially mailable only if it has never contained fuel or has been completely purged; an item that still has fuel or vapors in it is not mailable, and simply draining it doesn’t make it acceptable. Gasoline itself can never be mailed.

• Car batteries: USPS Publication 52 lists spillable automobile lead-acid batteries as nonmailable corrosives; only the non-spillable type is permitted under specific conditions.
• Air bag modules and seat belt pretensioners: these contain inflators classed as hazardous materials, and not all of them are mailable. Check Publication 52 and the carrier’s hazmat rules before you ship one.
• Fluids: oil, coolant, brake fluid and transmission fluid should be drained, and the part cleaned and sealed, before it ships by any carrier.
• Freight shipments: heavy parts that still count as hazardous materials need proper classification and paperwork; the guide to shipping hazmat via LTL freight covers labels and the dangerous goods declaration.

How Do You Pack Car Parts So They Arrive Undamaged?

Metal parts are dense and often have sharp edges, so most damage comes from the part moving inside the box and punching through it. Pack to stop movement, not just to cushion.

1. Drain and clean. Remove all fluids, degrease the part, and let it dry. Bag it in heavy plastic to contain any residue.
2. Protect critical surfaces. Cap or tape open ports and lines, wrap threads and sealing surfaces, and pad sensors, connectors and glass.
3. Use the right container. A double-wall box for parcels with at least 2 inches of cushioning on every side; a crate or pallet for heavy parts.
4. Immobilize the part. Fill every void with dense foam or cardboard so nothing moves when you shake the box; for freight, bolt or strap the part to the pallet.
5. Seal and label. Tape every seam with the H-tape method, remove old labels, and place the new label on the largest flat surface.

Glass and electronic parts such as headlights, mirrors and control modules need extra protection; the guide to shipping fragile items and valuables explains box-in-box packing.

How Do You Ship Car Parts Step by Step?

1. Create a free ParcelPath account. There’s no subscription, per-label fee, minimum or contract.
2. Enter the package details: origin and destination ZIP codes, the packed weight and the box dimensions.
3. Compare UPS and USPS services. Check the price and delivery estimate for each, and switch to freight if the part is too heavy or large.
4. Add insurance for valuable parts and buy the label.
5. Print the label or use a printer-free code, then drop the box at a UPS or USPS location or schedule a free USPS pickup.

You can run these numbers before you commit by entering the weight and dimensions in the ParcelPath rate calculator, which compares live UPS and USPS rates side by side. The shipping calculator guide explains how weight, zone and dimensions affect the result, and the article on pricing products with a shipping calculator helps parts sellers build shipping into their listings.

How Do You Ship Heavy Car Parts on a Pallet?

Engines, transmissions, rear ends and large body panels usually ship as LTL (less-than-truckload) freight, where your pallet shares a truck with other shippers’ freight. LTL is priced by weight, freight class, distance and any extra services you need.

1. Drain, clean and seal the part. LTL carriers generally expect engines and transmissions to arrive fluid-free and capped.
2. Secure it to a pallet. Bolt the part through its mounts or strap it down, then crate it or shrink-wrap it so nothing can snag.
3. Weigh and measure the loaded pallet, including the pallet itself, so the quote matches what the carrier finds.
4. Request a quote and book. ParcelPath’s PalletPath lets you get an LTL quote in the PalletPath freight quote tool.
5. Add accessorials you need. Residential pickup or delivery and a liftgate are common for parts going to or from a home garage.

The broader overview of delivery services, from ground to freight compares when each makes sense for large and heavy items.

How Can You Ship Car Parts for Less?

• Don’t pay retail. ParcelPath gives you up to 85% off UPS and up to 89% off USPS retail rates at no cost to you.
• Right-size the box. Light, bulky parts such as bumpers and grilles are billed by dimensional weight, so trim the box to fit.
• Use USPS for small, heavy parts. USPS doesn’t apply dimensional weight to packages of 1 cubic foot or less, which helps dense parts like calipers.
• Stay under size thresholds. UPS Large Package charges start past 130 inches in length plus girth, so measure before you box a long part.
• Palletize sets. Four wheels or a box of heavy parts on one pallet can cost less by freight than several parcels.

When you’re shipping more than one part, our hub of shipping guides covers related items, including how to ship car seats.

Can You Ship Car Parts Overnight?

Yes. UPS Next Day Air and USPS Priority Mail Express are the common ways to get a part to a shop fast. Priority Mail Express accepts up to 70 pounds with a 1–3 day money-back guarantee, and UPS Next Day Air goes up to 150 pounds, so heavier parts like cylinder heads usually have to go UPS.

Air services are stricter about hazardous materials, so batteries, air bag modules and any part with fuel or oil residue generally can’t go in a standard overnight box. Before paying for air, check the UPS Ground transit estimate; to nearby destinations it often arrives in one or two business days.

Frequently Asked Questions

What is the cheapest way to ship car parts?

For parts up to 70 pounds, the cheapest way to ship car parts is usually a discounted USPS Ground Advantage or UPS Ground label, compared side by side for your route. USPS often wins for small, dense parts because it skips dimensional weight under 1 cubic foot. Heavy parts like engines are usually cheaper on a pallet by LTL freight.

Can you ship car parts through USPS?

Yes. USPS accepts car parts up to 70 pounds and 130 inches in combined length and girth with USPS Ground Advantage. The part must be free of fuel and vapors, and spillable lead-acid batteries are not mailable. Clean and bag greasy parts so residue can’t leak, and pack them in a double-wall box.

How do you ship an engine or transmission?

Drain every fluid, clean the part, and cap all openings. Bolt or strap it to a pallet, crate or shrink-wrap it, and weigh the loaded pallet. Engines and transmissions exceed parcel limits or become impractical as parcels, so they ship by LTL freight, often with a liftgate for delivery to a home or small shop.

Do you have to drain fluids before shipping car parts?

Yes. USPS won’t accept an item that still contains fuel or fuel vapors, and simply draining a fuel-bearing part doesn’t make it mailable; it must be completely purged. Oil, coolant and transmission fluid should also be drained, and the part cleaned and sealed, before you ship it by any carrier, including freight.

Sources

• USPS: What Does USPS Classify as Hazardous Materials?
• USPS Publication 52, 348: Corrosives (lead-acid batteries)
• USPS Publication 52, 349: Class 9 Hazardous Materials (air bags)
• USPS: Priority Mail Express
• UPS: Shipping Dimensions and Weight
• UPS: How To Avoid Shipping Charge Corrections

Ready to ship? Compare discounted UPS and USPS rates with ParcelPath and print your label in minutes.