t's half price weekend at the you-pull yard near me. I scouted out a '92
Legacy SS with a used auto tranny I needed. Car was bashed in on the side which
is probably why it was there. Fluid was nice & red. Inside the car I
found a receipt for labor to replace a transmission, and the tranny
itself had a rebuilder's tag on it. Woot! I thought- rebuilt
transmission for $50! I dropped the pan just to double check before I
pulled the tranny and this piece of something was inside-- does anybody
recognize it? It looks to have been about 3" in diameter at one time and
is not metallic. Hard to replace? Tranny project is on 'hold' 'til I
figure it out.

a piece of a previous transmission gasket?

There is a plastic thrust washer that is on the trans oil pump, it supports the reverse drum.  It's 2.8" in O.D. by 0.065" thick.  There shouldn't be much thrust force on the reverse drum, so it might be okay to run without it, but it will be metal-on-metal.  If it were mine I'd take the trans apart and give it a once over.  It's the first thing you will see once you get the oil pump housing off.

 

 

Edited May 26, 201312 yr by presslab

Is it a tennis ball? Hard to tell without a picture.

 

*edit - Lol, nevermind I see you double posted.

Edited May 26, 201312 yr by Godsmulligan

Thanks Presslab! That sure looks like what it is. I traced around the arc and measured it at a bit under 3" and it is plastic- not flexible enough to have been a gasket but not hard enough to have been friction material either.

that is the plastic end thrust washer that keeps the drum from eating the pump housing should be replaced all you have to do is pull diff pinion then gentaly pull cast pump housing off replace washer and put back together i would not run it thiss way as it will allow the transs internals to move back and forth and will damage it. When its gone it will hesatate into gears and clunk into reverse

Sorry missed one thing it alows the assembly to shuttle and i can block passages and will start to eat lower drum support basket

There is a separate needle thrust bearing for the rest of the gears, that plastic washer only supports the reverse drum.

i would probably look for another trans.

no reason to buy one that needs work when there are others out there that don't.

The Legacy SS trans is special.  It is stronger than the normal ones.

 

Here is a quote from Subaru:

The 91 Model Year Update Course gives the following tranny info to consider; 

 

In order to handle the increased torque produced by the turbocharged engine, the 4EAT Transmission uses a larger Torque Converter. For additional strength, the input shaft has also been shotpeened. In both the Forward Clutch assembly and the High Clutch assembly, the number of drive and driven plates has been increased by one (1), while the retaining plate thickness has been reduced. The Low/Reverse Brake assembly has increased the number of plates by two (2), but the thickness has been reduced. The outer diameter of the Servo piston (band application) assembly has been increased in order to provide more band clamping force. Of course, the servo piston seals have also been enlarged to match the servo piston diameter. Due to the new piston shape the number of "O" ring seals has been reduced by one (1) Lubrication passages have been added to the Planetary Carrier assembly for increased gear durability.

Off the top of my head to replace that washer you'll need some sealant (I use Loctite 518), the oil pump gasket 31339AA122, extension gasket 31337AA120, pinion nut 802622020, and the washer 31299AA000-AA060 depending on thickness.