Description

Koehring 6655L, 6644L 1988 Parts Catalog

If you are wrenching on a Koehring 6655L or 6644L logger, you need the actual factory part numbers. Aftermarket listings? Not worth the paper they are printed on. This is the 1988 Parts Catalog, 28 pages, straight from Koehring Cranes & Excavators. It tells you exactly which bolt, which washer, which seal goes where. I have seen too many guys guess on a swing gear bolt and then watch the whole assembly walk apart. That torque spec on page 2 – 640 ft-lbs dry, uncoated on those inner race bolts – you miss that and you are buying a new gearbox. This catalog is your insurance against that kind of mistake.

Torque Specs and Fastener Details

Page 2 has the inner race bolt torque: 640 ft-lbs dry, uncoated. That is not a suggestion. It also shows the soft spot on the inner race must face toward the side of the machine. Miss that and the ring gear alignment goes to hell. The catalog lists capscrews, hardened washers, lockwashers – all with exact part numbers. You need a 1-inch x 6 Gr. 8 capscrew? Part number 310V3915. No hunting through bins, no cross-referencing. Every fastener spec is right there.

7 Systems Covered in the Parts Breakdown

The catalog covers the carbody and ring gear assembly (page 1.1), the track frame, final drives, hydraulic plumbing, cab components, engine mounting, and the boom/arm group. Each section has an exploded view with callouts. You get the part number, description, and quantity. The note on page 1 says to specify model number, serial number, and description when ordering. That means you need this catalog to get the right part the first time. No returns, no downtime waiting for the wrong gasket.

Does This Catalog Cover Aftermarket Replacements?

No. This is OEM-only. Aftermarket parts catalogs often use generic illustrations and skip discontinued part cross-references. This one has a discontinued part note – see the bottom of page 1.1: “DISCONTINUED PART! REFER TO NUMERICAL PARTS LIST FOR REPLACEMENT PART(S).” That is a factory supersession. You will not get that from a third-party list. If you are buying used parts or rebuilding with OEM, this catalog saves you from ordering dead stock.

Source Validity: Why This Matters for the 6655L and 6644L

This is not a scan of a scan. It is the original Koehring publication from 1988. The note on page 1 gives the Chattanooga Operations phone number – (615) 267-4511 – and the litho date. That is provenance. The parts list on page 3 is a bill of material with engineering stamps and date changes. Authentic factory data. You show this to a parts counter and they will take you seriously. I have been a tech for 28 years and I will take a factory catalog like this over any aftermarket CD every time. Pair it with the Koehring T-S44, 644 1974 Parts Catalog – Factory OEM Parts Reference or the Koehring S-155 1977 Parts Catalog – Factory OEM Parts Reference if you have other models in your fleet. For hydraulic hoe work, the Koehring 366 Hydraulic Hoe Parts Catalog – OEM Factory Specs is another solid reference.

Who Needs This Catalog?

Home garage guys who bought a 6655L at auction and want to rebuild the undercarriage. Small logging outfits that do their own maintenance. Shops that take in Koehring equipment and need reliable part numbers. If you are a beginner, this catalog will teach you the correct terminology – like the difference between a capscrew and a bolt – and keep you from ordering a set of inner race bolts that are too short. The exploded views show assembly order. You can use this alongside a service manual to confirm fastener grade and torque. The Automotive Industry Overview on Wikipedia gives some background on heavy equipment standards, but for actual part numbers, this catalog is what you need.

How to Identify Your Machine

Page 1 has a line for serial number. Your 6655L or 6644L serial number must match the range on the cover. Without that, you risk ordering parts that fit a different production run. The catalog is model-specific, but there are variations between early and late 1988 builds. Write your serial number in the blank. If you need to understand the industry context, check the Automotive Industry Overview for general manufacturing history.

How do I know if this catalog fits my 6655L serial number?

Page 1 has a serial number blank. The original file covers serial numbers from 12261-139 up to later runs. If your machine falls outside that, call Koehring with the catalog’s part number U356E0085 to check.

Does this catalog include hydraulic system part numbers?

The catalog covers the carbody, ring gear, and undercarriage in detail. For hydraulic components like pumps or control valves, you need the separate hydraulic parts manual. This one focuses on structural and drivetrain parts – 28 pages of gear, bearing, and fastener specifics. If you are rebuilding the swing circle or final drive, this is the one.

Do not waste time with photocopies that lost the torque table. Get the actual 28-page factory catalog. Access the Factory Manual and keep it on the workbench next to your torque wrench.