Can Servicing a Transmission that has not been Maintained Cause it to Fail Prematurely?

This question was sent in from a customer out of Grapevine, Texas:

Hi,

I have a 1999 expedition with the 5.4L engine. I am on the second transmission. The First transmission was replaced at 100,000 miles and had a trans cooler installed at that time. The truck now has 209,000 (109,000 on 2nd trannie). I don't remember if I have had the fluid serviced in the last 100,000 miles. The local garage will not service the transmission, claiming that since it has gone so long without a service, the junk floating around is keeping the transmission together and that I would have a transmission failure if I replace the fluid and filter. Does this sound right to you?? Should I service the transmission??

Sincerely,
Forgetful Joe

This was my response:

Hi Joe,

There is some truth about a service causing damage to a transmission that has not been maintained properly. However, I don't think it will be an issue with your transmission. I would recommend a standard pan drop service so that we can see what kind of debris are in the transmission. Hopefully, we'll find a normal amount of material in the pan, change the filter and fluid, and give you back a sense of security when it comes to the transmission in your Expedition.

The myth of the old fluid keeping the transmission together was more true years back. Automatic transmission fluid (ATF) has high amounts of additives and detergents to help keep all of the small parts moving freely. 20 Years ago, the glue used to bond the paper clutch material to the steel plates was not as good as today's bonding agents. What would happen is, the old transmission fluid would break the glue down if not serviced regularly, then when the new high detergent fluid was pored in, it would literally wash the clutch material off of the steel plates. Better fluids and better parts have made it much safer to service transmissions that have been neglected. 109,000 miles out of a rebuild is great, considering it didn't last that long when it was new. The cooler that you had installed is most likely the reason for it's long, trouble free life.

The service that can damage the transmission at this point is a flush. A flush is a common technique for cleaner servicing of transmissions and to replace all of the fluid in the transmission and torque converter. The problem with the flush is, it can stir up the normal amount of materials that transmissions produce over life, and send that material into delicate moving parts of the transmission. This can result in abnormal shifting, check engine lights, and possibly catastrophic failure.

I also suggest we find a transmission specialist to perform your service. They'll know what to look for when servicing your transmission just in case there is a problem forming. I have a few shops in your area that are being evaluated for Peoples Certification. I will contact you with their information first thing in the morning.

I look forward to talking with you more.

Jon Rodriguez
Peoples Transmission
1-888-415-2098