I have just rolled 100,000 miles on my Explorer and have never had the transmission oil changed. There does not appear to be any issues and I have heard this is a weak point in this vehicle.
My question is should I have it serviced or leave alone? I can see the benefit of clean oil in the system, but I have heard if it is not broken, do not fix it.
Your thoughts and opinions?
Doug
Tranny fluid fails on heat breakdown (from overheated use - like heavy load towing over mountains, hard driving in city traffic, etc.). Once overheated, it cannot do it's job and the tranny then begins to fail due to lack of lubricating ability of the damaged fluid.
Tranny fluid can also cause failure when it becomes overloaded with contaminants, which can result in circulating contaminanats through the system, in addition to sludging up your hydraulic control passages and control valves.
There are some who will tell you that this tranny should already be dead; however, fortunately for you, it's more complex than that. If the tranny has never had a fluid change and has been abused and overheated, then it probably is already a 'dead tranny spinning'.
Therefore, if it is case #1 - not abused just never changed, I recommend that you do have the tranny fluid and filter changed (note - changed, NOT flushed).
If it is case #2 - abused and a ticking bomb, I recommend that you do the same - have the fluid and filter changed (not flushed).
No need to panic. just get 'er done. Make sure that the right fluid goes in for sure.
In either case, if it holds together after that for a year or so, I would then have it changed again.
Note that many of these trannies have gone well over 100K miles, you just don't hear about them on a site where people share the horror stories.
Good Luck.
