As a transmission rebuilder, it's not enough to merely get your hands on the correct overhaul kit for the unit you're working on. Even the 'right' overhaul kit from some brands don't actually contain all of the parts you need to finish the rebuild job. As we've said before, not all overhaul kits are made equal in terms of quality. The same goes for completeness: not all overhaul kit manufacturers take the care to include every single component you need for a complete rebuild.
To save yourself time, effort, and productivity in your shop, it's best to research your overhaul kit ahead of time to ensure it includes every component you need to rebuild the unit from the start. Here's what to look for in order to determine if you're using the most complete transmission overhaul kit on the market.
What Complete Overhaul Kits Include
All aftermarket sealing component manufacturers must put in a certain level of research in order to compile an exhaustive bill-of-material for their overhaul kits, but the difference between complete kits and incomplete kits generally points to the depth of that component research. When real transmission units are torn down and analyzed, OE parts are identified and sourced, and component weaknesses are identified and improved upon, the manufacturer willing to put in all that work is the one that ends up with the best, most complete overhaul kit offering.
There are two main elements that are incorporated into complete overhaul kits: soft parts and variation components.
Transmission Soft Parts
All transmission overhaul kits should contain every single soft part necessary to fully rebuild a broken or failed transmission unit. Whether your shop chooses to replace only worn and damaged parts or every part regardless of its condition, having a complete overhaul kit means that even the smallest soft parts are all present and accounted for. Soft parts include paper gaskets, sealing rings, O-rings, D-rings, metal clad seals, lathe cut seals, and bonded pistons. (For information on the differences between overhaul and master kits, check out our recent blog post.)
What many incomplete overhaul kit manufacturers fail to account for are the variations that occur during the production of particular transmission applications. Earlier versions of the same applications may have changed in design or assembly somewhere along the line, so later variations of the same application require different parts. A truly complete overhaul kit is created to match the exact variation of the application in the vehicle you're rebuilding to ensure no parts are missing (or added unnecessarily).
The True Value of a Complete Overhaul Kit
Using a complete overhaul kit on every transmission rebuild that comes into your shop will ultimately save you time and money. When you have to wait for your kit manufacturer to send out the correct parts that were missing from the kit, that means there's a vehicle taking up space in your shop, costing you the business you must turn away because your space and schedule is full. A complete kit also allows your business to avoid comebacks in the future because your techs have everything they need to finish the rebuild accurately on the very first try. At the end of the day, your shop simply can't afford to risk using an incomplete overhaul kit.