Quote:
Originally Posted by JCL
I was referring to many documented failures, swissfranks being only one of them. While some are snap rings, others are temperature sensors, wiring, actuators, or broken metal pieces that are static, ie not dependent on lubrication. What these failures have in common is a lack of connection to fluid condition. One could make a case that the various o-ring failures are related to the fluid condition, but it would be only a guess.
I hear your point on the filter, but do you have data that suggests that clogged filters are causing transmission failures? I equate fluid failures with burnt clutch plates, and clogged filters with low fluid pressure, again often appearing along with burnt clutches and evidence of overheating. The overheating failures we have seen documented have been linked to mechanical failures that resulted in overheating, ie the burnt components were a result, and not a root cause.
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I think most people will replace a transmission or sell the car if it slips regularly even if it still does shift eventually because it no longer meets their perceived needs.
I had an '89 Chevrolet Celebrity SW that I bought used and the PO had done some partial replacement of the fluid 60-70k miles prior to my ownership, but the filter was never replaced. I eventually sold it at 167k miles due to very rough shifting, believing the tranny was about to go out. The guy I sold it to several years ago still drives on the same tranny, rough shifting and all.
The level of operation did not meet my standards, but to him, it still drove and he was content with that (I sold it to him for scrap value).
I have a '00 Subaru Outback SW that I bought used with 42k miles on it. It now has 135k on it on the original transmission. I changed the transmission fluid on it at 55k, 88k, and 115k. I did not change the filter until 115k because I followed the recommendation from subaru that the filter is "lifetime". Until I changed the filter, there were metal particles on the dipstick (yes it does have an AT dipstick) and in the fluid along with somewhat rough shifting. I may have "gottn away" with not changing the filter due to my frequent fluid changes that got the metal and clutch material out reguarly. I cut open the old filter and it was full and choked with PM. After that experience, to me "lifetime" means as long as they want you to own it for so that they can sell you a new car!
To me it makes sense that unfiltered particulate matter of all sizes being constantly recirculated into all the inner workings will either cause serious operating problems or may contribute to a CTF.
Also, I don't think AT filters are analogous to fuel filters, but are more like oil filters in that once the flow restriction is too high due to cold weather or clogging, the filtration is bypassed and line pressure is maintained.