Problem when car came back from shop

I took my car in for some work, as I have no time these days, and don't have a garage right now.

While they had the motor out I asked the shop to install my new converter I have been sitting on for the last 6 months or so. They also replaced my tansmission filter , replaced the fluid, and gave the case a good pressure wash(Almost looks new!).

After I got the car back today they mentioned that it looks like I am going to need a new tranny soon as it is starting to slip.

The tranny came to me used from a FABO Member who assured me it was in fine working condition. It seemed like it worked OK to me for the small amount it was run before it went into the shop. (I am not blaming the guy who I bought it from)

The transmission does seem to be slipping a lot, especially when I get to about 3000 RPM. it also seems to be having issues when I slow down finding the proper gear and really starts slipping almost like it is in neutral. When the kick down is engaged, the slipping is very pronounced as well, and it seems like it is having a hard time picking a gear.

I did check the fluid , and it was a bit low (1/2 Quart), so I topped it up, still not fixed.

Specs:

904 transmission with Fresh fluid and filter
ACC Boss Hog Full size convert 22-2800 stall

I have never driven a car with a performance converter so I was not sure what to expect. I assume this is not how converter slip is supposed to be?

Any thoughts?

Perhaps something was bumped/missed/removed when the pan was dropped?

Converter not properly installed?

I am going to take it back to my guy, and ask him to have another look at it, but if I had some suggestions it would be nice. He is a decent guy and has done good work for me in the past, but he is not a tranny guy, more of a general mechanic shop.

The really sad part is I just gave away a known good 727 to another FABO member a couple months ago, since this one seemed to be OK. Hopefully the giving away good parts Carma will come back to me and this will turn out to be something silly/cheap to fix#-o
Author: admin