Lexmex

Well, some of you might have been aware of an experiment that I was going to run over the weekend, running without a transmission filter.

I can tell you right now, do not run without one.

Without the transmission filter in place, it fires an inordinate amount of fluid down this hole right here in blue., and I wound up with some leaks around the gasket. Luckily, I had an extra gasket from the old Rav4 transmission (though I can pick one up for a Camry at Toyota here, that is the same). I personally, think these cork gaskets are garbage, but the one off the old transmission appeared to be made of some rubber composite and my uncle commented it was definitely superior to using the cork.

What I noticed was that upon driving back to my apartment, it took off like a bat out of hell. I am very sure I would blown any 1/4 mile record. Shifts were lightning fast, but no sooner than I got home did I notice a slight leak on the corner of the gasket by the tranny pan bolt. My cousins eventually came over and we changed out everything on the spot and put the rubber gasket and paper filter back in (that I had just removed).

However, I decided to ponder this issue, especially by taking a look at the Rav4 tranny (which is a U140F like mine) and take a closer look at the possibilities of why it failed. I made a discovery which I would like to share with the forum.

Lexmex

This is the bottom of this damaged tranny (I will be bringing it to Florida with me). Now, unrelated to what I am about to mention, notice the part in the lower left. It appears to be torn or have broken metal in this area.

Also notice that the filter is the wire mesh filter, not the paper-like fiber material used in the current filters.

Lexmex

A closer shot of that lower left corner.

salimshah

FIPG is the rubber cement. When I did my son's sc trasnmission. You keep the tube in fridge. You make a continues bead and need to install in 10mins or less. Pain to clean it when you take it off.

FIPG -> form in place gasket (my best guess)

Salim

Fipg is for pan gasket.

Lexmex

Now I removed the magnets at the bottom of the pan. The transmission guy who worked on my own transmission back in December had opened this one and found some stuff on the magnets (a lot more), but he had a another comment I will reveal in a bit.

Let's take a look at these magnets and some shots of the front differential plug and tranny plug.

Lexmex

Another shot.

Lexmex

A small bit in my hand.

Lexmex

The wire mesh filter.

Lexmex

Another shot

Lexmex

Now, I shook this filter and it was like chock full of nuts, and it had a lot of bits in the filter, but no tears that I could see in the filter.

The interesting thing was is that when we poured some of my old ATF into on to this, it flowed like liquid sunshine, effortlessly. Seemed like it let through a good amount of flow, which I thought would be good and was my reason also for trying to go without a filter (since I change my ATF very often).

Lexmex

Here was a bit that fell out of the filter.

Lexmex

Now here's the fiber filter the other day on my tranny.

Lexmex

Here is my filter again.

Here's the thing. When we removed this filter, out came what I would guess was about a liter or so ATF.

I asked the tranmission guy on Saturday what came out when he opened up the RAV4 tranny, he said nothing, perhaps maybe a few drops. My uncle and I poured some old ATF on this fiber filter and it held quite well.

Now, this goes back to a comment of the transmission guy that he observed that the Rav4 tranny, seemed to have suffered from some fluid loss, either low level or complete loss, though he speculated low level. Right now, I am using that very same gasket and it is holding up quite well with no leaks on my end

What my theory is here is that perhaps with this screen mesh filter on earlier models it may have a allowed too much to pass into the lower part of the pan, and in conjunction with either a regular or lower level of fluid), such amount pouring through could have the potential to leave upper areas of the transmission without fluid at the necessary time. Keep in mind that I overfill a bit. This could be a reason for the pump having an issue since it is higher up. I didn't see any other damage on the lower side of this tranny.

However, perhaps the use of this fiber like filter serves a good purpose in keep the fluid in the upper area of the transmission.

Just a theory.

thomas1

Funny I just read on the Ford site from a guy that had a brand new filter that was leaking at the seam (crimped edge outside on the filter) and the Truck was missing shifts and acting really bad. Finally replace the new (defective ) filter and the truck worked fine. Kind of supports your theory on needing some sort of back pressure on that area, but what blows your theory is that our cars came with the wire mesh and worked fine. at least for a while. I cant remember what type is in mine at this time, but it is getting time for me to drop my pan and check filter and magnets. When my tranny failed it had the paper filter in it and their was metal everywhere. Another mystery.

Lexmex

Well, here's the thing, most of the earlier designs of the U140 came with this wire mesh screen OEM, but what we would need to find out is that when we have these failing trannies, just what filter is being used at the time of failure. However, possibly by the time the paper filter was put in the, the damage was done given that the wire mesh filter was in there for so long. Again, what I do is overfill up to the IV on the tranny dipstick.