the trans was not re done correctly we have seen this many times

the 2 main drums in the unit one being the foward clutch it has a riverted plate in the clutch drum, shops that do not do enough of this type of unit have no idea that the O Rings the factory put under the plate in the drum can be replaced ,

when we buy a rebuild kit we ask for this Special O ring kit as well as the re program valve body KIT They do not come in the regular OH major OH Kit -- all together its pricy but you need to do it all not just at the time what is worn,

and thats what i think they did, if they do it again they may even mis it again and end up charging you twice for what they dont know < we have had many sent to us from other shops to be fixed -- jz