FR396 ???? there is no FR396.
Did you mean FR936 ?
If so , it is 36 tooth not 32 and there are no upgrades you can do to it, the Dual 80 style ratchets are different.
Also the SR80 is a 1/2" drive ratchet so that kit definitely won't fit and neither will the 3/8" drive FR80 as I stated the dual 80's are completely different internally and will not fit any other ratchets.
For the record there are no " tooth upgrades " for the 900 or 800 series ratchets.
Also if you go to the thread mentioned above and go to the Snap On page that hofferwood posted about, be aware that there are MANY mistakes in that listing showing the wrong repair kits.