Carrier Transicold 17-57026-00 Shaft Seal Assembly — 05G Twin Port Compressor

The reservoir bottle is the tell. Once it's filling, the seal has already lost the oil film.

The 17-57026-00 is the current Carrier Transicold shaft seal assembly for the 05G Twin Port compressor — the six-cylinder open-drive workhorse under Supra, Ultra, Ultima, X2 and X4 trailer units. It is a complete assembly: bellows, carbon rotor, stator, O-ring, lip seal and cover gasket. Everything the crankcase needs to stay sealed where the crankshaft exits into the weather.

This is the part number Carrier moved to. Per Carrier Transicold Performance Parts bulletin PTS16-002 (20 January 2016), the 17-57026-00 superseded the older 17-44770-00 after material changes were made specifically to enhance shaft seal reliability. Carrier confirmed the new seals are backwards retrofittable — if your unit ran a 17-44770-00, the 17-57026-00 drops straight in. You are not buying the old part; you are buying the fix.

Why this seal is the hardest-working part on your compressor

The 05G is an open-drive compressor. The crankshaft physically leaves the crankcase to pick up the clutch or belt drive, and a mechanical face seal is the only thing standing between your refrigerant charge and the atmosphere at that exit point.

It is not a gasket. It's a precision tribological system running two lapped faces — a soft carbon-graphite rotor against a hard stator seat — separated by a lubricating oil film roughly one micron thick. Carrier feeds it deliberately: oil branches off the pump circuit, passes through a metering orifice into the shaft seal cavity to lubricate and cool the faces, then drains back to the crankcase through an overflow passage. The seal reservoir bottle taps the same cavity to catch anything that gets past.

That film is the seal. The faces never truly touch. And that's the entire design brief.

What it lives through

Across that rpm band the sealing interface sweeps roughly 160 to 865 surface feet per minute — continuously, over the road, through vibration, road salt, thermal cycling and flooded starts. A passenger-car A/C seal never sees a duty cycle like this.

The tolerance nobody sees

Seal faces aren't measured in thousandths. They're measured in helium light bands, using an optical flat under monochromatic light. One helium light band equals 0.0000116 inches — 0.3 microns. Half the wavelength of helium light.

Industry practice for a carbon-graphite face is 2 to 3 light bands of flatness, with harder counterface materials held to 1 to 2. That's a total geometric deviation on the order of 23 to 35 millionths of an inch across the entire sealing surface. Typical lapped seal face surface finish runs 4 to 5 µin, with hard carbon sitting near Ra 0.1 µm.

Two facts worth carrying into the bay with you:

1. Flatness and surface finish are different things. A face can be mirror-smooth and still be warped enough to leak. A face can be flat and still be too rough to build a film. Both have to be right, and they are controlled by different processes.
2. Carbon relaxes after lapping. Manufacturers lap carbon to under one light band, but the material moves. Reading three bands on the bench is normal, not a defect — it pulls back flat once clamped against the hard mating seat. Techs scrap good carbons over this every day.

That is the precision you are buying. Not a rubber ring — a lapped optical surface with a working clearance thinner than a bacterium.

Understand who builds parts like this — and to what standard

Carrier does not machine every component in a 05G. Seals, elastomers and lapped faces come from specialist sealing manufacturers — the same tier of supplier that serves the wider refrigeration compression industry with carbon-graphite faces, elastomer bellows and precision-lapped mating rings.

What matters isn't the logo on the box. It's the quality regime the supplier is held to. Carrier publishes its expectations openly in its Supplier Quality Manual (QLY-02). It is a serious document, and it is the benchmark we build against:

• Certified QMS required — ISO 9001, IATF 16949 or AS9100 through an accredited third-party registrar. Suppliers without one face an on-site Carrier audit and must reach Level 2, re-audited at least every three years.
• PPAP Level 3 is the default — design records, PFMEA, control plan, measurement system analysis, full dimensional results, material and performance test data, initial process studies, and a signed Part Submission Warrant. No shipping before the warrant is approved.
• Key Characteristics under statistical control — Carrier's ProCert methodology requires Cpk ≥ 1.33 on variable key characteristics, demonstrated over a minimum of 25 consecutive observations (or 30 days of output, whichever is greater) with zero non-conformances.
• Gauge R&R capped at 20%, revalidated at least every 24 months. If you can't measure it repeatably, you don't control it.
• Annual product revalidation — full dimensional verification, process certification summary, current material certifications.
• Ten-year record retention, six months' written notice before any process or material change, and a stated objective of zero defects.

What's in the box

The 17-57026-00 is supplied as a complete seal assembly, matched as a set:

• Bellows assembly — the flexible, shaft-driven element that carries the rotor and accommodates end play, run-out and wear
• Rotor (carbon-graphite ring) — the lapped soft face
• Stator — the hard mating seat, lapped to match
• O-ring — seals the stator's outside diameter into the cover or clutch hub
• Lip seal — the secondary barrier that seats in the cover/hub
• Cover gasket — the crankcase joint

Rotors and stators are lapped as matched pairs and must be replaced together. Carrier is explicit on this point: never install a new rotor against a used stator, and never reuse a seal assembly or gasket. Mixing a new face against a worn one guarantees a leak path, and it wastes the new part.

⚠️ Order the right one: 17-57026-00 vs 17-57027-00

These two are easy to confuse and constantly get cross-shipped.

If your gland plate or clutch mounting hub is scored, cracked, or the lip seal bore is damaged, you want the -27, not the -26. If your cover is serviceable and you're just replacing the seal itself, this is your part. Not sure? Send us a photo of the cover face — we'll tell you straight.

Installation notes for the tech doing the job

Not a substitute for Carrier workshop manual 62-11052. But these are the details that decide whether the seal lasts a season or five years.

Torque values

• Shaft seal cover / clutch mounting hub capscrews (3/8-16): 30 – 50 ft-lb (4.1 – 6.9 mkg) — diagonal pattern
• Oil reservoir capscrew (3/8-16): 8 – 15 ft-lb (1.1 – 2.1 mkg)

Orientation is not optional. The cover or clutch hub must go on with the "TOP" stamp straight up, so the oil communication hole in the cover lines up with the port in the crankcase. Get this wrong and you have starved the seal of the oil film that is the seal. It will run hot, glaze, and fail early — and it will look like a bad part.

Use the right lubricant on assembly. Carrier specifies alkylbenzene oil — CTD P/N 07-00274 (Zerol 150) — even on R-134a and R-404A systems. POE is extremely hygroscopic; it pulls moisture out of the shop air, and that moisture becomes acid inside your system. Do not lube a shaft seal with POE straight from an open jug.

Handle the faces like optics. Don't touch the lapped surfaces with bare fingers. If they get contaminated, clean with isopropyl alcohol and a clean, dry, lint-free cloth — nothing else.

Use the tool. Carrier's 05G Shaft Seal Tool is 07-00460-00; the lip seal driver for the cover plate is 07-00471-00. Prying a bellows assembly on with screwdrivers is how carbon rings get chipped.

Align the rotor. The notches in the rotor must engage the two small knurls inside the seal seat. If it doesn't drop in cleanly, it's not aligned — don't force it.

Inspect the lip seal in the cover. Any sign of wear or damage and it gets replaced. Make sure its back side seats on the machined shoulder.

Then service the reservoir. The shaft seal reservoir holds about 3.5 oz and should be checked and drained at least once a year. That oil is contaminated — dispose of it properly, never return it to the compressor.

Break-in reality

A freshly installed mechanical face seal needs run time to bed the faces and establish its film. A small amount of initial seepage into the reservoir during break-in is normal behaviour for this design — that's precisely why Carrier fitted a reservoir. A reservoir that keeps filling is not break-in. That's a seal, a scored shaft, a starved oil feed, or an orientation error.

While you're in there — diagnose the cause

Seals rarely die of old age alone. Before you close it up, check the things that killed the last one:

• Oil level between MIN and MAX on the sight glass, read right after shutdown while the compressor is warm
• Oil pressure holding 15–18 psi above suction
• Discharge temperature under 275 °F (250 °F on POE)
• Belt tension not exceeding 300 lb of load
• Mounting angle within 30° of shaft centreline
• No flood-back — liquid in the cylinders can spike pressures toward 1,500 psi and hammer everything downstream of it

Fit a new seal to a compressor that's overheating, running dry, or seeing flood-back and you'll be doing it again before the season's out.

Fitment

Carrier Transicold units:

• Optima
• Supra — 950, 950MT, 960, 960MT
• X4 — 7300, 7500
• Ultima — 53, XTC
• Ultra — XL, XTC, XT, Ultra
• Extra — XT
• X2 — 2100A, 2100R, 2500A, 2500R

Compressor applications: 05G Twin Port · 05G · 05G37 · 05G41 · 05G42

Confirm by compressor model and visual match before ordering. Unsure? Call or text 403-996-1480 with your unit model and serial number — we'll verify before you buy.

Cross Reference

Replaces or is compatible with the following Carrier part numbers, including formatting variants:

17-57026-00 · 175702600 · 17-5702600 17-44770-00 · 174477000 · 17-4477000 17-44150-00 · 174415000 · 17-4415000 17-44140-00 · 174414000 · 17-4414000 17-44043-01 · 174404301 · 17-4404301

Cross-references are provided for identification and interchange only. AVRO Parts is not affiliated with, endorsed by, or sponsored by Carrier Corporation or Carrier Transicold. All OEM part numbers, names and marks are the property of their respective owners.