Transmission Rebuild vs. Replace

  No one ever says, “I think it’s time to start saving for a transmission”. When a transmission fails, it is typically unexpected and a financial burden. I know from experience, having been associated with over 30,000 transmission repairs and rebuilds over the last 35 years. There is buzz online and in the automotive repair industry that replacement, or “remanufactured transmissions”, is the better choice. Contrary to popular belief, however, remanufactured transmissions are similar, if not the same as a rebuilt transmission.

Soft Parts

Inside an automatic transmission, there are two types of parts. The first type is known as the transmission’s soft parts. Soft parts are wearable pieces inside your transmission that eventually will need to be replaced. Soft parts come in rebuild kits; rebuild kits are also known as overhaul kits and can be bought in different sizes. Smaller rebuild kits have less parts, while larger kits come with more parts. Inside some kits, you will find clutches, seals, sealing rings, internal and external gaskets, and other wearable items that are replaced at the time of rebuild. Some kits have even more pieces such as steels, bushings, bearings, bands, and washers. Most pieces can be purchased individually as well as in a kit.

At the time of rebuild, soft parts (clutches, seals, sealing rings, internal and external gaskets) and the filter are usually replaced. There are times when a shop can offer to only do a pin point fix, depending on the rest of the parts or the budget of the customer. This would mean that the shop was only replacing what was needed to bring the transmission back to working order. A good transmission shop will be searching for the failure and the cause of the failure so the problem doesn’t return after repairs are completed. Pin point fixes can be very cost effective and dependable, and can last as long as overhauls (rebuilds), which I have seen in my own experience. Some customers prefer to replace the wearable items, and this is fine. Typically soft parts are replaced at the time of rebuild. Bushings are typically replaced as needed, and the same goes for bearings and washers. If you want all of the “soft parts” changed at the time of rebuild, make sure to request that type of rebuild kit.

Hard Parts

Hard parts are parts made of steel or aluminum inside your transmission. They do not normally go bad, but when they do they can be bought used, re manufactured, or new. Excessive hard part damage can drive up the costs of repair. Some Hard Parts inside the transmission are called pumps, drums, planetary, housings, shafts and the valve body.

When a pump is bad, it can be resurfaced or replaced with used, remanufactured, or new equipment. Pumps are rebuilt during the transmission rebuild process. Bushings inside the stator of the pump or the pump cover bushing are very common to be replaced at time of transmission rebuild. The front seal and sealing rings on the stator are also replaced. When buying a new pump, they can be expensive depending on the application. Resurfacing a pump body or pump cover is time consuming, and it is more cost effective to replace the pump with a re manufactured or used pump that is in good condition.

Drums are typically replaced as needed. A drum is a holding fixture for clutches. Drums can be purchased used, re manufactured or new. My rule of thumb is if a drum has damaged clutches, then replace the drum, though it is not always a necessary procedure. A drum can be rebuilt with new rings on the pistons and work as good as new. Drums can crack at tig welds, and fail where bushings ride and warp. In some cases, the drum can be the cause of failure, but in most cases the drum and clutch pack are damaged by the cause of failure.

The planetary assemblies inside your transmission are very durable. They typically do not fail, but there is always the possibility that they can. Usually if a planetary has been damaged, it has been damaged by another source. Extreme lack of maintenance can cause planet failure. In most cases, planet failure is caused by lack of internal lubrication. Planets (planetary assembly) can be purchased used, re manufactured or new. Planetary assemblies can be rebuilt, but it is time consuming, and generally considered more practical to replace the assembly in most cases. If your working on a 722.99 Mercedes 7 speed automatic, a new planetary assembly can cost thousands of dollars. A re manufactured assembly or used planet set in good condition will be as durable and a more cost efficient option that will last just as long as new (as long as the cause of failure is found and corrected).

The Valve body can make or break a good transmission rebuild. The valve body can be replaced as needed with used, re manufactured or new parts, but is typically cleaned and reused. The valve body inspection, cleaning, and re-assembly is one of the most critical parts of the entire transmission overhaul procedure. Cars and trucks today have electrical components called shift solenoids attached to the valve body. These shift solenoids help shift the transmission, and can be replaced with new or used parts or, in some cases, rebuilt. Most transmission rebuild shops will know what to do to make sure your valve body is a dependable part of transmission operation.

Automatic Transmission Updates

It is said that remanufactured transmissions have special powers. The remanufactured transmission has been updated to exceed the manufacturer’s specifications, and these aftermarket updates correct all the problems that the manufacturer didn’t get right at the time of design. Some after market updates are in some overhaul kits, while others are bought as needed. Good transmission repair shops have the experience to know which updates are the best. Some transmissions just don’t work that well; they shift sloppily from the factory. Sometimes computer updates can correct transmission shifting concerns.

Updates are available for all different parts of your transmission. Personally, I am a big fan of a shift kit on certain transmission types at time of overhaul. A shift kit on certain transmission applications makes the transmission feel better when it shifts, though the same transmission will last just as long without the shift kit. Internally speaking, there are no special updates available to remanufactured transmission suppliers. When a Honda Odyssey has a torque converter clutch failure (or not), it is industry standard to update the pressure regulator valve inside the transmission. It is also common practice to do an end plugs update in the valve body at time of overhaul, install a external transmission cooler, etc. This is only one of many examples. Internal and external transmission updates are available to all transmission rebuild centers.

Pro’s and Con’s of Remanufactured (replacement) Transmission vs Rebuilding the Original

Remanufactured transmissions tend to be much more expensive. It may be the mark up of the transmission installer of the replacement transmission, or the transmission supplier who supplies the transmission to the installer. If a remanufactured transmission is available locally, it can be a quicker turn around on completion of repairs. When rebuilding the transmission in your vehicle, it will typically take 3-5 business days and sometimes more. In some cases a remanufactured transmission installer may be able to get a transmission locally and install it, saving rebuild time.

Rebuilding your original transmission can in some cases cost thousands less than a replacement transmission. Reusing the good parts and only replacing the bad tends to be a more cost effective method than the latter method of remanufacturing. A transmission rebuild of your original transmission will be equivalent to a re manufactured (replacement) transmission in relation to quality and updates, but it may take more time to complete the repair.

Warranty Remanufactured (replace) vs Rebuild Original

The warranty is typically very similar between the two. Most transmission rebuilding facilities have different warranties and transmission repair types to fit your repair needs. The warranty on a  remanufactured (replacement) or rebuilt transmissions is always negotiable. Most transmission replace experts will pay the installer for the removal and installation of the transmission in the event of a warranty repair. Rebuilding your original transmission will usually include a warranty that includes the removal and installation in the event of a warranty claim.