Transmissions: Repair or Replace?

The factors to consider before deciding the best option.

Downtime will, in most cases, impact the profits of an owner operator or fleet engaged in over-the-road hauling. In these applications, a quality “reman” product will typically be the better choice rather than days or weeks of downtime. 

Having confidence that the unit will be reliable for the long term is another reman advantage.


For those individuals or fleets planning to operate their vehicles for one or two years, they may not want to invest in replacing the transmission and opt for a repair. That decision may be a sound one.

On the other hand, with more and more fleets extending buying cycles and looking at vehicle service lives of four to five years or more, they may want to consider a reman or other replacement product and the reliability, performance, service and warranty features that are included with the product. 


While all failures are bad, some are not as bad as others, and the possible scenarios are countless. That noted, here is a look at a few examples that can influence the repair versus replace decision.

Definitely consider a replacement transmission when a failure occurs in the main case assembly. For example, replace the transmission in a situation where an overdrive gear cracks and runs through the transmission, damaging multiple gear sets. 

Also, consider replacement if a cooler blowout occurs, possibly cooking the inside of the transmission. 

In both scenarios, the repair can be very time-consuming and there is no guarantee the root cause of the failure will be fixed.

But, you may want to consider repairing for issues along the lines of harsh shifting that may be related to the air system on the transmission. A leak in the system may be occurring, requiring nothing more than replacing the rear seal. 

Another minor repair may be related to slow or incomplete shifts caused by oil ingestion in the back box. The remedy may be as simple as replacing the range bar. 

It doesn’t make good sense to pursue a replacement with these and other minor repairs.

With failure types, it is also important to note that certain transmission problems may not have anything to do with the actual transmission. Excessive driveline vibration, for example, can cause synchronizer pins to break.

You can repair the problem all day long, but the failures will continue to occur until you fix the vibration problem. Swinging into a reman product, of course, will be just as futile. Fixing the vibration will fix the transmission.


Often when repairing a failed transmission, the root cause of the problem is not properly addressed. Damage to additional internal components often results from the initial failure leading to additional repair bills down the road. 

Those costs can add up quickly. When that becomes more of the norm than the exception, it may be a good time to consider a replacement transmission.

In the case of Eaton’s Fuller Reman transmissions, keep in mind that each transmission has been 100 percent inspected. Crack and leak inspection, bore diameter gauging, bearing replacement and dyno testing are just a few of the precautions Eaton takes to ensure best-in-class reliability. And with the exclusive use of genuine components, a more robust and reliable product is built to generate consistently lower lifecycle costs.


Warning signals during the day-to-day operation of a transmission may also help determine the merits of replacement versus repairing. 

For example, a slow shift when shifting between gears may require a simple repair, much like the case with the back box range bar noted earlier. But if there is a lot of vibration and excessive noise coming from the transmission, then a replacement may be the best option.

The vehicle operator plays an integral role in determining just how severe noise, vibration or harshness is in the transmission. 

In any event, that information should always be given to a qualified and trained technician or service center so they can determine the cause of the problem and then determine whether it is best to replace or repair.


While the pros and cons of replacing versus repairing are many, the best advice we at Eaton can give is to always deal with an experienced and properly trained service provider. Also, be sure that provider always uses genuine, OEM-approved components.

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